US2279657A

US2279657A - Air conditioning system

Info

Publication number: US2279657A
Application number: US254839A
Authority: US
Inventors: Robert B P Crawford
Original assignee: Individual
Current assignee: Individual
Priority date: 1939-02-06
Filing date: 1939-02-06
Publication date: 1942-04-14
Anticipated expiration: 1959-04-14

Description

April 14, 1942.

2 Sheets- Sheet 1 Filed Feb. 6, 1959 ,finomtor m]! 18.19. (Bmuwizmmil GHOURQ April 1942- R. B. PNCRAWFORD 2,279,657

AIR CONDITIONING SYSTEM Filed Feb. 6, 1939 2 Sheets-Sheet 2 A mmrmmcmdom I attorney Patented Apr; 14, 1942 UNITE.

stares PATENT OFFICE Ara CONDITIONING SYSTEM Robert B. P. Crawfqrd'Miami, Fla. 3 Application February. 6, m9, Serial Nazsasas 14-Claims.. (c1.- sz-e) eration system having an evaporator and condenser which are selectively connected toa space heat exchange means to thereby provide for heat- I ing or cooling the space without altering the op-' eration of the refrigeration system.

Another object is the provision of a system of this type which utilizes first and second space heat exchangers which are alternately connected to the evaporator and condenser of theTefrigeration system.

A further object is the provision of a system of this general type which utilizes a storage tank for storing conditioned medium and in which the temperature of'the stored medium is automatically controlled. Still another object is the provision of a timing arrangement for stopping the refrigeration system during peak load periods and for. varying the temperature of the stored medium prior to such periods to provide for carrying the system through such periods.

Other objects will appear from the following description and the appended claims. Y

For a full disclosure of this invention, reference is madeto the following detailed description and to the accompanying drawings, in which Figure 1 illustrates diagrammatically. an air conditioning system embodying the principles of this invention, and

Figure 2 is a wiring diagram of the controlsystem of- Figure 1.

' Referring to the drawings, reference character I indicates a conditioning chamber having an in-.

let 2 for freshair. The discharge end of this conditioning chamber is connected to a fan 3 which in turn is connected by a dischargeduct 4 to the conditioned space 5. This conditioning chamber contains a first heat exchanger 6 which.

acts as a precooler for the air in summer and as a preheater for the air in winter. Also located in-chamber l is a second heat exchanger 7 which acts as a cooling coil in summer and as a heating coil in winter. While chamber I is illustrated as receiving fresh air only, this chamber may-be arranged to receive .a mixture of fresh air and air recirculated from the space 5, if so desired.

The' cooling and heating system includes a. mechanical refrigeration system having a compressor 8 which is driven by an electric motor 9 controlled by a three speed starting box it). T e

outlet .of the compressor 8 is connected by a discharge line H to the refrigerant inlet of a condenser !2 which is diagrammatically illustrated as comprising a casing housing a cooling coil 53.

The refrigerant outlet of the condenser i2 isconnected by a liquid line [4 to a solenoid valve I5 which is in turn connected by pipe l6 to an evaporator l1; This evaporator i1 is provided with a coil l8. Thetop of the evaporator I! is connected'to a suction line l9 having a trap .20

interposed therein for removing any liquid refrigerant which may be withdrawnfrom the evaporator. The trap is provided witha drip conduit 22 which is connected to the inlet pipe "5. The solenoid'valve I5 is controlled by means of afloat switch Ml which is responsiveto the level of the liquid refrigerant in the evaporator l'l. This float switch opens and closes the valve l5in a manner to maintain a constant liquid refrigerant level inthe evaporator andthus causes theeVapora'tor E1 to be flooded. As well understoodin the art, the condenser 12 acts to remove heatfi'om the compressed refrigerant. thereby liquefying it, and this liquid refrigerant evaporates within the evaporator I! for causing the.

coil It to be chilled. e d

Reference character 25 indicates'a circulating pump which is driven by an electric motor 26. The inletofv this pump is connected to a pipe 21 which extends into a well 28. The discharge of pump 25 is connected to a pipe 29 which leads to the inlet of the coil 6 located within the conditioning chamber l.' The water flows through this coil in'counterflow relation with the air flow through the conditioning chamber.

' outlet of coil 6 is connected to a pipe 30 which in The turn is connected to valves 3| and 32, The outlet of valve 3| is connected to a pipe 33' leading to the inlet of .coil l8 within the evaporator l1, and the outlet of this coilis connected by a pipe 34 which is in turn connected to valves 35'and 36. The outlet'of valve 35 is' connected to pipe 31 which leadsinto a sump 38 which is connected to the well 28 by a subterranean ditch 39 located below the prevailing water table. The

valve 32 is connected to a pipe 40 which leads to the inlet of the coil [3 in condenser H. The outlet of this coil is connected by a pipe 4! to a modulating valve 42 which is in-turn connected by pipe 43 to the inlet of a three-way valve 65.

One outlet of this three-way valve is connected by pipe 45 to a storage tank 46, this tank inturn being connected. by pipe 41 to the pipe 48 which extends between valve 36 and the inlet of a pump Y 49. This pump is driven by a motor 50 havingv a starter The outlet of this pump is connected by a pipe 52 to the inlet of coil 1 in conditioning chamber I. The water or other heat exchange medium passes through this coil I in counterfiow relationship to the air being conditioned, and leaves this coil through a pipe 53' which is connected by pipes 54 and 55 to -

valves

56 and 51, respectively. The second outlet of the three-way valve 44 is connected by a pipe 58 which leads to the sump 38. The pipe 46 which leads to the inlet of coil I3 in condenser I2 is connected to a city water service pipe 59, the flow through this pipe being controlled by means of a valve 66 which is controlled by a proportioning motor 6|.

The valves 3|, 32, 35, 36, 56, and 51 may be solenoid valves which are adapted to close when deenergized and to open when energized. In a manner which will'be explained hereinafter, the valves 3|, 35, and 51 are energized when the system is operating on the winter cycle and these valves are marked W. The

valves

32, 36, and 56 are deenergized during the winter cycle and are energized during the summer cycle and are accordingly marked S.

Thus during the winter cycle, the W valves are open while the S valves are closed With the valves in these positions, the pump 25 will act to withdraw water from'the well 28, which water will be higher than the temperature of the incoming air. This water will be discharged through the pipe 29 into coil 6 through which it flows in counterflow relationship with the air thereby preheating the air. This water will then flow through the pipe 36, valve 3|, and pipe 33 into coil l8 of the evaporator l1, and thereby provides a source of heat for this evaporator. This water will-then flow through pipe 34, valve 35, and pipe 31 into sump 38 from which'it may flow through the subterranean ditch 39 back to the well 28. The water in flowing through this ditch located below the water table will absorb storage tank 46 if the valve 44 is positioned to permit this.

Also at this time, the pump 49 will withdraw cold water from the coil' l8 of evaporator l1 through pipe 34, valve 36 and pipe 46. This cold water will pass through the pipe 52 into the coil 1 for thereby cooling the air being passed to the space. The water leaving this coil will flow through pipe 53, pipe 54, valve 56, and pipe 33 to the inlet of coil |8 in the evaporator l1.

From the description thus far, it will be apparent that during both the heating cycle and the cooling cycle the pump 25 will act to withdraw water from the well 28 and pass it through the coil 6 in the conditioning chamber l. During the heating cycle this will act to preheat the air and during the cooling cycle this will act to pre-;

1 is passed directly back to the inlet of coil I8. I

When the system is operating on the heating cycle however, the water leaving the coil 6 which then acts as a preheater will pass directly into coil l8 of evaporator [1 for thereby-providing a. source of heat and the cold water leaving coil l8 will pass to the sump 38. At time, hot water is withdrawn from the storage tank 46 and passed through the coil 1 in conditioning chamber I. This water then passes through valve 51 into the inlet of coil l3 in which it is heated, the

heat from the surrounding sub-strata and water.

At the same time, water will be withdrawn from the storage tank 46 through

pipes

41 and 48 by the pump 49, this pump discharging this water through the pipe 52 and into the coil 1. The

water will flow from the coil 1' through pipes tank 46. This storage tank may have a take-oil 46a' for domestic hot water.

During the cooling cycle the W valves 3|, 35, and 31 will beclosed while the

S valves

32, 36, and 56 willbe open. At this time, the well water will be cooler than the 'air passing over coil 6 and consequently the pump 25 in forcing water from the well 28 through coil 6 causes the air to be precooled. The water flowing from the coil 6 passes through pipe 36, valve 32, and pipe 46 intothe coil l3 of condenser l2 for condensing the compressed refrigerant. The heated water flowing from .coil |3 passes through pipe 4|, valve 42, and pipe 43 to the three-way valve 44. This water will then flow through the pipe 58 back to the sump 38 if the valve is in the position illustrated, or will flow through the pipe. into the The water in flowing through i ire.

hot water passing through the

valves

42 and 32, valve 43 back into storage tank 46. Thus in summer the coil 1 receives cold water from the evaporator I1 and .in winter this coil receives hot water from the condenser l2.

Referring now to the controls for the system. reference-character indicates a thermostat responsive to outdoor temperature, this thermostat controlling a motor 66 operating a step controller 61. This step 'controller 61 is connected to the W and S valves and acts to open the

S valves

32, 36, and 56 when outdoor temperature rises above 15 F. and to, open the W valves 3|, 35, and 51 when outdoor temperature falls below 60 F. This step controller 61 also is connected to the pump motor starter 5| for stopping trolled by the step controller 61. This relay 16 acts to place the step control motor 69 under the control of a summer spacethermostat 11 when theoutside temperature is above F., while placing this step control motor 69 under the con-.

trol of a winter space thermostat 12 and a. low limit discharge thermostat 13 when outside temperature is below this value. The step controller 61 also operates through a relay -14 in the compressor starter for preventing operation of the compressor when outside temperature is between .60 F. and 75 F.- The three-way valve 44 and the city water valve 66 are selectively controlled by means of a pressure controller 15 on the hot water tank 46 through a relay I6 which is controlled by the step controller 61. 'This relay acts to place the controller I in control of the valve 6| when the system is operating on the heating cycle while placing the controller in controlof the three-way valve 44 when the system operates on the cooling cycle. valve 82 is controlled by a thermostat TI which is responsive to the temperature of the water in tank 46 and also by a timer I8 which functions to vary the setting of controller IT in .a manner to increase the temperature of the water in tank a 46 to a predetermined value before a peak load period for the power service approaches.

the compressor during such peak load periods.

The throttlin This timer 18 also functions to prevent operation of Referring now to Figure 2, the details of the 1 control system 'will be described. The outside thermostat 65 is preferably of the potentiometer type and is diagrammatically illustrated as comprising a bellows 89 connected by tube 8| to a bulb 82 located in the fresh air inlet. This bellows actuates a bell-crank lever having an actuating arm 83 connected to a spring 84 and a slider' 85 which cooperates with a control resistance 86 to form a control potentiometer. It will be apparent thatupon rise in temperature of the fresh air the bellows .89 will expand thus causing movement of slider 85 to the right along resistance 86 against the action of spring 84, and that upon fall in temperature the bellows 99 will contract under the action of'spring 84 "for causing movement of' the slider in the opposite direction. This instrument maybe so designed and adjusted as to cause slider 85 to engage the righthand end of resistance 86 when outdoor temperature is at or above 75 F., while engaging the lefthand end of this resistance when outdoor temperature is at or below 69 F.

The motor 66 which actuatesthe step controller 61 is preferably of the type shown in the Taylor Patent No. 2,028,110. This motor is connected to the thermostat 65 and is adapted to assume angular positions corresponding to the position of the slider 85 on resistance 86. This motor 66 is provided with a shaft 81 which carries the

step controller cams

88, 99, and 99. These cams cooperate with suitable followers for actuating mercury switches 9|, 92, and 93, respectively. When outside temperature is at or above 75 F., the shaft 9! of motor 66 assumes the extreme clockwise position shown at which the raised portions of earns 98 and 99 just engage the cam followers for tilting mercury switches 9| and 93 so as to bridge the left-hand electrodes of switch 9|, and the electrodes of switch 93. At this time, the raised portion of the and 51.

mercury switch 9| will be closed. When outside temperature is between 75 and 60 F., the mercury switches 92 and 93 will both be open and mercury switch 9| will be tilted for bridging its right-hand electrodes. When outside temperature is below 60 F., the mercury switch 92 will close and the right-hand electrodes of switch 9| will remain bridged.

The mercury switches 9| and 92 control the

S valves

32, 36, and 56 and the W valves 3|, 35, When the outside temperature is at or above 75 F., the switch 93 is closed and the switch 92 is open as described above. Due to switch 93 being closed, a circuit will be com-' V the mercury switch 92 is open and the W valves 3|, 35, and 51 are deenergized and consequently are closed. -When outside temperature falls below 75 F., but is above 60 F., both the S valves and W valves will be deenergized, due to mercury switches 92 and 93 being open. Upon fall in outside temperature below 60 F., the mercury switch 92 will close which will complete "a circuit from the transformer secondary 94, wires 96, IN, and I92, mercury switch 92, and wire I93 cam 89engages the cam follower for mercury switch 92 and tilts this switch to open position. Upon fall .in outside temperature, the slider 85 of thermostat will begin to move to the left on resistance 96 which causes proportionate rotation of shaft 81 in a counter-clockwise 'direction. This immediately causes the raised portions of

cams

88 and 99 to disengage their respective cam followers thereby tilting mercury switch 9| for bridging'its right-hand electrodes and tilting. mercury switch; 93 to'open position. When outside temperature falls to 60 F., the shaft 81 will have rotated sufficiently to cause the raised portion of cam 89 to disengage itsfolr lower for thereby tilting mercury switch 92 to through Wvalves 3|,35, and 5'! in parallel to wire I99 and wires I95, 99 and I99 to secondary 99. Therefore when outside temperature is above'75 F., the

S valves

32, 36, and 56 are open and the W valves 3|, 35, andSI are closed. When outside temperature is between '75 F. and 60 F., all of the valves will be closed, and when the 3|,35, and 51 will open.

Referring now to" the compressor speed con trols, the compressor motor 9 is of the threespeed type and is provided with the three-speed starting box I9. This three-speed starting box is provided with a common terminal connected to wire I91, a low speed terminal connected to wire I98, an intermediate speed terminal connected to wire- I99, and a high speed terminal connected to wire II9. The wires I98, I99, and III) lead directly to the step controller 68 and the wire I9'I leads to the relay 19.

.The relay I9 may be of any desired type .and is diagrammatically illustrated as including a pull-in coil III which actuates a switch arm -I I2 through a suitable armature II3. .When coil III is energized, the switch arm H2 is caused to engage contact I'M, whilewhen coil III is deenergized the switch arm II2 disengages contact II4 due tothe action of gravity of springs; not

The step controller 68 includes cams II5,'II6, and II! which' are mounted upon the shaft II8 of motor 69 and which through suitable followers actuate mercury switches II9, I29, and I2I., The cams H5, H6, and III are attached .to the shaft 8 in staggered relationship so that upon clock wise rotation ofshaft II8, the mercuryswitches closed position. It will therefore be seen that when outside temperature is at or above F the mercury switch'92 will be open,, the mercury order stated. .When the shaft III; of motor 69 is in its extreme counterclockwise position, the

- mercury switches I I9, I29 andIZI will all beopen and consequently the compressor motor 9 will not operate. As shaft II8 rotates in a clockwise direction, mercury switch II9 will first close. As-

suming that relay 14 is energized, a circuit will be completed from the common terminal of starter I through wire I01, relay 14, wires I22 and I23, mercur switch I I9, and wire I08 to the low speed terminal of the starter I0 thereby causing the compressor to operate at low speed. Upon further rotation of shaft II8, thevmercury switch I20 will close for thereby completing a circuit from the common terminal through this switch and wire I09 to the intermediate-speed terminal for causing operation of the compressor at intermediate speed. Upon still further rotation of shaft II8, the mercury switch I2I will close for I completing a circuit through wire IIO to the high speed terminal thereby causing the compressor to operate at high speed. From the foregoing, it will be-apparent that the compressor speed will vary in accordance with the angular position of the shaft II8 when the relay 14 is energized, It will also be apparent that when relay 14 is deenergized, the compressor will not operate regardless of the position of shaft H8.

The motor 69 is preferably of the type-shown in the Taylor Patent No. 2,028,110 and is controlled by the relay 10, the summer thermostat H, the winter thermostat 12, and the discharge thermostat 13. Thesummer thermostat may be of the potentiometer type and includes a bellows I25 which actuates a bell-crank having an actuating arm I26 biased by a spring I21, and a control arm or slider, I28 which cooperates with a erg ized, the switch arms engage the out contacts.

As mentioned before, the motor 69 is preferably of the type shown in the Taylor Patent 2,028,110. This motor includes three control terminals which are marked R, W, and B, and is adapted to assume intermediate positions depending upon the relative values of resistances connected between'terminals R and W and between terminals R and B. When equal resistances are connected between terminals R and W and between terminals R and B, this motor will assume mid position as shown which causes closing of mercury switches H9 and I for operating th compressor motor 9 at intermediate speed. If the resistance between terminals Rand W is decreased without corresponding decrease resistance I29 to form a control potentiometer. 1

Upon an increas in space temperature, the bellows I25 will expand against the action of spring I21 for shifting the slider I28 to the left along resistance I29, while upon decrease in temperature the bellows I25 will contract under the action of spring I21 for shifting slider I28 in the opposite direction. This instrument may be so designed and adjusted as to cause the slider I28 to engage the right-hand end of resistance I29 when space tempera-ture is at or below"15 F..

while engaging the left-hand end of this resistance when space temperature is at or above 80 The winter space thermostat 12 may be exactly the same as the summer thermostat H and includes a slider I30 and a resistance I3I. This instrument may be designed and adjusted in a manner to cause the slider I30 to engage the lefthand end of resistance I3I when the space temperature is at or above 72 F., while engaging the right-hand end of this resistance when the space temperature. is at or below 70 F. I

The discharge thermostat 13 may be similar to the spacethermostats-H and 12 and includes a bellows I32, a slider I33, and a resistance I34.'

actuates through a suitable armature the switch arms I38, I39, and I which cooperate with in contacts I4I, I42, and I43, respectively, and also which cooperate with out contacts I44, I45, and 46, respectively. When coil I31 is energized, the switch arms I38, I39, and I40 engage rthe in contacts, while when coil I31 is deen in resistance between terminals R and B, the motor 69 will operate in a counter-clockwise direc-' tion for decreasing the-compressor speed, and conversely, if the resistance between terminals R and B is decreased without corresponding decrease in resistance between terminals R and W,

the motor 69 will operate in the clockwise direction for increasing the compressor speed,

The pull-in coil I31 of the relay I0 is controlled by the mercury'switch 9I of the step controller 61. When outside temperature is at or above F., this mercury switch will be tilted as shown for bridging its left-hand electrodes and this will energize pull-in coil I31 as follows: transformer secondary 94, wires 95, II and I50, left-hand electrodes of switch.9 I wire I5I', pull-in coil I31, and wires I52, I05, 99 and I00 to transformer secondary 94.

It will thus be apparent that when outside temperature is at or above 75 F., the coil I31 will be energized for causing the switch arms I38, I39 and I40 to engage their in contacts. However, when outside temperature is below 75 F., these switch arms will engage their out contacts.

Assuming that outside temperature is above 7 5 F., thereby energizing the relay I0, the switch arms I38, I 39,and I40 will engage the in contacts, as shown. Engagement of switch arm I39 with contact I42 will connect terminal R of the motor 69 to the slider I28 of the summer thermostat 1I through wire I53, switch arm I39, contact I42, and wire' I54. Engagement of switch arm I38 with contact I4I will connect terminal W of motor 69 to the right-hand end of resistance 429 through wires I55 and I56, while engagement of switch arm I40 with contact I43 will connect terminal B to the left-hand end of resistance I29 through wires I51 and I58. Consequently, the summer thermostat H is placed into control of the motor 69 which controls the compressor speed, With the space temperature at an intermediate value, the slider I28 engages the. center of resistance I29 which divides the resistance I29 equally between terminals R and W and terminals Rand B. This causes the motor 69 to assume the position shown at which mercury'switches H9 and I20 are closed for operating the compressor at intermediate speed. Upon rise in space temperature, the slider I29 will shift to the left along resistance I29 thereby decreasing the portion of this resistance which is between terminals R and B, while increasing the portion between terminals R and W. This will cause the motor 69 to rotate proportionately in the clockwise direction thereby causing closing of the switch I2I for operating the compressor at high speed. Upon'decfease in space temperature from this intermediate value. the slider I20 will shift to the right along resistance I29 thereby decreasing the. proportion of this resistance which is between terminals R and W, which will cause the motor 63 to operate in the counterclockwise direction thus tilting mercury switch I20 to open position which will cause the compressor to operate at low speed. Upon continued decrease in space temperature, the motor 69 will rotate further in the counterclockwise direction thus causing opening of switch 123 to stop the compressor when the space temperature falls to 75 F. Therefore, when outside temperature is at or above 75 F., the summer thermostat H is placed in control of the compressor, acting to place the compressor into operation at low speed when space temperature rises above 75 F. and to graduatingly increase the compressor speed upon increase in space temperature for causing the compressor to operate at maximum speed when the space temperature rises to 80 F.

When outside temperature falls below 75 F., the mercury switch 3| of step controller 61 will be tilted so as to unbridge its left-hand electrodes and bridge its righthand electrodes. This unbridging of the left-hand electrodes will break the energizing circuit or the relay 10 thereby causing the switch arms I38, I39 and I40 to engage their out contacts. This will completely shifts to the right along resistance I34, it acts 69 for causing this motor to increase the compressor speed. Thus as the discharge temperature falls below the setting of the discharge thermostat 13, this thermostat actsto increase the compressor speed independently of the thermostat 12 for thereby preventing the discharge-temperature from falling too low. It will be noted that resistance I68 is connected to the wires I5I and I65 and is thus connected across terminals R and B of motor 89. The purpose of this resistance is to balance out the effect of the resistance I34 of controller 13 which is connected between terminals R and W of motor 69 when this thermo-= stat is in satisfied or normal position. -This resistance I68'should be equalin value to the resistance I34.

From the description thus far, it will be seen that when the outside temperature is above 75 F., the summer thermostat H is placed in control of the compressor speed controller and acts in a manner to increase the compressor speed as space temperature increases. When outside temperature falls below 75 F., the step controller .61 deenergizes the relay 10 which disdisconnect the summer thermostat from the.

motor 69. Engagement of'the switch arm I39 with contact motor 69 to the slider I33 of the discharge thermostat 13 by wires I53, I60 and I6I. If the slider I33 is engaging the left-hand end of resistance I34 as occurs when the discharge temperature is sufficiently high, this circuit from terminal R of the motor will be carried through wire I62 to the slider I of the winter thermostat 12. Due to the switch arm I38 engaging contact I44, terminal W of motor 69 will be connected to the left-hand end of resistance I3I by wires I55 and I63.- Also due tothe switch arm I40 engaging I will connect terminal R ofconnects the summer thermostat H from the compressor speed controller and places the win- I ter space thermostat 12 and the discharge controller 13 in control of the compressor speed controller. At this time, the controller 12 acts to increase the compressor speed upon fall in space temperature and the discharge thermostat 13 acts to prevent the discharge temperature from falling below the desired value.

contact I46, terminal B of motor 69. will now be connected by wires I51, I64, and I65 to the righthand end of resistance I3I. Therefore when the relay 10 is deenergized' and the discharge temperature is at or above 65 F., the thermostat 12 will be in control of the step controller motor 69. If the space temperature is above 72 F., terminals R and W of the motor will besubstantially shortcircuited for thereby rotating the shaft I I8 of the step. controller in a direction for stoppingthe compressor. As the space temperature decreases below 72 R, the slider I30 will begin moving to the right across resistance I3I thereby inserting 'aportion of this resistance between terminals R and W and removing. this resistance from between terminals R andB. This will cause the'motor shaft I I8 to rotate proportionatelyin a clockwise direction thus starting the compressor and increasing its speed as the space temperature falls.

,It will. be noted thatthe right-hand end'of connected by Wires 161,166, I-65,.I 64,.contact; I46,

stat 12 thereby decreasing the efiect of this thermostat upon the motor. Also as the slider I33 Referring now to the controls for tank- 46, it will be noted that this tank is closed at its top to provide an air space abovethe water level. The water level with this tank is controlled for maintaining a substantially constant pressure within the tank, the pressure controller 15 being selectively connected to the valve 60 or the valve 44 through the relay 16. The pressure controller 15 may consist of a bellows I10 which is connected to the tank 46 by .atube I1I. This bellows actuates a bell-crank lever having an actuating arm I12 and a slider I13 cooperating with a resistance I14. Upon increase in pressure within tank 46, the bellows I10 will expand against the action of spring I15 for causing the slider I13 to shift to the left acrossresistance I14. This instrumentmay be adjusted in a manner to cause the slider I13. to. engage the lefthand end of resistance I14 when ,the tank pressure is at 40 poundspe'r square inch and to engage the right-hand end-{of ..resistance. I13

when th essure is ago? below mpdunldszper .Sq-uareinch n The relay 15 include '4 a coil I 16, which actuates switcl arms I11, I18, I19, I80, aii d'I8I. The switch arms I11, I18, ,I19,Ia nd I80. cooperate with.foutiflpontactS, I02, 83,184, and I85Eand switcharms- I18, 'I19, l 8f0,.andl I8 I cooperate with in contacts I86, I81, I88, and I 8j 9'.". When the c unt i 'deenergized, t e switch arms l 11, [l8,,I19 and I80 engage their out contacts and when' the coil .I 1I5is energized, the switch arms I18, I19, I80, and 1,8 l ,.engage their respective in contacts. The coil I16 is .controlle d'by the merci ry swi tch" of the outdoor temperature .step controller.61'.'. Wheri outdoor temperature falls, below F.. the mercury switch 9I istilted for bridging its rightliand electrodes. "I'lfiswill energize coil I16 as follows: transformer secinto tank 46.

ondary 94, wires 98, IOI and I50, right-hand elec- V trodes of switch 9|, wire I90, coil I18, wires I9I,

I92, and I to secondary 94. Therefore'when outdoor temperature is below 75 F., the coil I16 is energized for causing the various switch arms to' engage their in contacts. When outdoor temperature is above 75 F., the coil I18 is de-- energized for causing the switch arms to engage their out contacts, as shown.

The three-way valve 44 is positioned by means of a proportioning motor I95 having terminals R, W, and B. When the relay 18 is deenergized due to outside temperature being above 75 F., the slider I13 of the pressure controller is connected to terminal R of motor I95 by wire- I98, switch arm I19, contact I84, and wire I91. Also, the right-hand end of resistance I14 is connected to terminal B by wire I98, switch arm I80, contact I85, and wire I99. At this time,

the left-hand end of resistance I13 is connected by wire 200, switch arm I18, contact I83, and

flowing through pipe 43 to be divided between the storage tank 48 and thewaste pipe 58. If the pressure within tank 48 falls due to withdrawing of water from this tank for domestic use, the slider I13 will shift ,to the left across resistance I14 thus decreasing the portion of this resistance between terminals .R and B for causing the motor I95 to position valve 44 in a manher to increase the flow of water into tank 48.

Conversely, upon increase in pressure with the tank 46, the slider I13 will shift to the left across resistance I14 thereby causing the motor I95 to position valve 44 for decreasing the flow of water When the pressure within this tank rises to pounds vper square. inch, the valve 44 will be positioned for preventing further flow of water into this tank.

When outside temperature falls below"15 F., the mercury switch 9| will energize the relay I18 for causing the various switch arms to disengage their out" contacts and to engage their in contacts. This will completely disconnect the pressure controller 15 from the three-way valve motor I95. Due to the switch arm I8I of relay 18 engaging contact 489, terminals R and Bof motor I95 will be short-circuited through wires I91, 202, switch arm I8I, contact I89, and

wire I99. This causes the motor I95 to position the valve 44 for causing all of the water flowing in pipe 43 to flow into tank 48.

I Due to-the relay 18 now being'energized, the slider I18 of pressure controller 15 will be conpipe 43, valve 44, and pipe 45 into tank at. When the pressure in the tank is above 40 pounds per square inch, the controller 15 will cause the valve to be closed, while upon fall in pressure below this value the valve 80 will be graduatingly opened.

When outside temperature is above 15 F., thus causing the relay 18 to be deenergized, the switch arm I11 engages the contact I82 which connects terminals R and W of motor 6| through

wires

203, 208, switch arm I11, contact I82, and wire 205. From the foregoing, it will be seen that when outside temperature is above F., the pressure controller 15 is placed in control of the three-way valve 44' and the valve.80 is driven to closed position. 'However, when outside temperature falls below this value, the pressure controller 15 is placed in control of the valve and the three-way. valve 44 is driven to a position for causing all of the water flowing through pipe 43 to flow into the tank 48.

The throttling valve 42 is provided for the purpose of restricting the'flow of water through the coil I3 in condenser I2 for, thereby insuring that the water is heated to the desired point during its fiow through this coil. This valve is positioned bya proportioning motor 208 which is controlled by the thermostat 11 responsive to the temperature of the water in tank 48. The thermostat 11 may comprise a bellows 209 which actuates a lever arm 2I0 against the action of spring 2. Thelever arm 2I0 actuates a slider 2I2 which cooperates with a resistance 2I3 to form a control potentiometer for the motor 208. This lever 2I0 also actuates a corrector arm 2I4 which cooperates with a center tapped resistance 2I5. The bellows 209 is connected by a capillary tube 2I8 to a,bulb 2E1 located in the tank 46 (Figure 1).

The right-hand end of the resistance 2I3 is connected by wires 2I8 and 2I8a to terminal B of motor 208 and the lefthand end of this resistance is connected by wires 2I9 and 220 to terminal W of this motor. rector arm 2I4 of thermostat .11 are electrically connected and the resistance 2 I5 is connected by wires 22I and 222 to terminal R of motor 208. Thus the slider 2I2 is connected to terminal R through the corrector arm 2I4 and corrector resistance 2I5. The thermostat 11 is of the wide range type and causes motor 208 to shift valve 42 from wide open position to a minimum flow position upon movement of the slider 2I2 over but a small portion of the resistance 2I3. This controller may be arranged so that the slider 2I2 engages the right-hand end of resistance 2I3 'when the water temperature rises to 160 F.

while engaging the left-hand end ofthis resistance when the water temperature falls to F. Upon a slight movement of the slider 2I2 to the right across resistance 2 I3, the resistance between terminals R and B will be decreased for nected to terminal R of motor. 8| which operates the valve 80 by wire I98, switch arm I19, contact I81, and wire 208. The right-hand end'of resistance I14 will be connected to terminal B of motor H by wire I98, switch arm I80, contact I88, and wire 204, while the left-hand end of resistance I14 will be connected to terminal W or motor 8| by wire 200, switch arm I18, contact I88 and wire 205.. Therefore the pressure controller 15 at this time is placed under the control of the valve 80 which controls the flow of city water through pipe 59 into the coil I3 of con- ,denser I2, and thus through pipe 4|, valve 42,

causing valve 42 to open'thereby increasing the flow of water through coil 43 for allowing the watertemperature to fall. Conversely, upon a slight decrease in temperature, the slider 2I2 will be shifted slightly to the left across resistance. 2I3 thus decreasing the resistance between terminals R and W of motor 208 for positioning the .valve 42 in a manner to restrict the flow of water.

pletely even when the motor reaches the end The slider 2I2 and cor-' of its travel. This prevents the flow of water through the condenser from being completely stopped by Valve 42.

It is a feature of this invention to prevent operation of the compressor during peak load periods for the power service and to provide for increasing the temperature in tank 46 at a predetermined time befoze the peak load period in order to-provide an adequate supply of hot water to last through the period when the compressor is stopped. This result is obtained by the timer l8 and a pair of compensating or adjusting

potentiometers

225 and 226. The timer 18 may consist of a suitably synchronous motor and gear train mechanism 221 having a shaft 228 which is rotated one revolution every twenty-four hours. This shaft 228 carries cams 229 and 230 which actuate mercury switches 23l and 232. -For purposes of illustration, it is assumed that only one peak load period occurs each day, and the cams 229 and 238 are provided with single raised por-' tions corresponding to the peak load period. It will be noted that upon clockwise rotation of the shaft 228, the raised portion of the cam 229 will engage its cam follower a predetermined time in advance of the time when the raised portion of the cam 23D engages its cam follower.

The mercury switch 232 controls the compressor relay M, the energizing circuit for the relay 14 also being controlled by the mercury switches 92 and 93 of the outdoor step controller 61. When outdoor temperature is above 75 F., the compressor relay 14 will be energized through mercury switches 93 and 232 as follows: transformer secondary 96, wire 96, wire 91, mercury 1 switch 93, wire 233, wire 234, mercury switch 232, wire 235, relay coil II I, and wires 99 and N16 to secondary 95. When outside temperature falls below 75 the mercury switch 93 will be opened which will break the circuit just traced for preventing operation of the compressor. When outside temperature falls to 60 F. for causing closing of'mercury switch 93, the energizing circuit for relay M will be established through this mercury switch as follows: secondary 96, wires 96, NH and I02, mercury switch 92, wire 236, wire 234, mercury switch 232, wire 235, relay coil Ill, and wires 99 and Hill to secondary 94. It will therefore be seen that the mercury switch 232 of the timer 18 is always in circuit with the compressor relay l4 and that when this mercury switch is open, the relay M is deenergized for preventing operation of the.

compressor.

'The mercury switch 231 has its common electrodes connected by wires 23! and 222 to terminal R of motor 208. The right-handelectrode of. this switch is connected by wire 238 to the slider 239 of potentiometer 226, and the left-hand electrode of this switch is connected by wire 240 to the slider 24! of potentiometer 225. The resistances 242 and 243 of these potentiometers are connected across terminals W and B of-motor 208, as shown. It will therefore be seen that the mercury switch 23l acts to place either the potentiometer 225 or the potentiometer 226 across the motor control terminals in parallel with the thermostat ll. Each of these potentiometers acts to determine the temperature of the water which will be maintained by the thermostat 11. For instance, if the slider 239 of potentiometer 226 is shifted to the right across its resistance 2 43, it will decrease the amount of resistance between terminals R and B and increase the amount of resistance between terminals R and W. This will cause the valve 42 to be opened further 'mercury switch 23| of timer [8 'will'place the potentiometer 226 into the control circuit of motor 208 for thereby causing the tank thermostat H to maintain a relatively low water temperature such as 125 F. As the peak load period for the power service approaches, the cam 229 will'tilt mercury switch 22 to its opposite position for removing potentiometer 226 from the motor control circuit and substituting the potentiometer 225. This will raise the water temperature maintained by the tank thermostat Thereafter, the cam 230 will cause opening of mercury-switch 232 for stopping the compressor during the peak load period. It will be apparent from the foregoing that during normal operation of the system, the tank thermostat 11 operates to maintain a relatively low tank temperature for thus'permitting the refrigeration system to operate ata low head pressure securing maximum operating efficiency. Then as the peak load period for the power service approaches, the

, timer I8 substitutes the potentiometer 225 into the control circuit in place of potentiometer 226 for thereby raising the tank temperature so as to store sufiicient heat for carrying the system '94 by wires I00, I92 and 254.

over the peak load period when the compressor is stopped.

Referring to the pump controller 5|, this controller may consist of a pull-in coil 250 'for operating a switch arm 25I engaging a contact 252. The pull-in coil 250 is connected to the mercury switches 92 and 93 by means of wire 253 and wires 233 and 236. The left-hand end of coil 250 is also connected to the transformer secondary It will therefore be apparent that whenever the mercury switch 92 or 93 are positioned for permitting operation of the compressor, the pump starter 5| will be energized for placing the pump 50 into operation Operation With the parts in the position shown, the outdoor temperature is above F. as indicated by the slider of the step controller 65 engaging the right-hand end of resistance 86. This has caused the step controller motor 66 to assume its clockwise limit of rotation at which the mercury switch 91 is positioned for bridging its left' hand electrodes, the mercury switch 92 is open, and the mercury switch 93 is closed. Due to the mercury switch 92 being open, the W valves 3i, 35, and 51 are closed while due to switch 93 being closed the

S valves

32, 36, and 56 are open. This closure of mercury switch 93 also has caused energization of the pump motor starter 5| for placing'the pump in operation and also has energized the compressor relay T4 through switch 232 of the timer 78 for placing the compressor under the control of the step controller 68.

Due to the S valves being openand the W valves being closed, cold water will be withdrawn With the sliders 239 and 24,l.in-the positions from the coil I8 of evaporator l1 through pipe 34 passing through valve 36 and pipe 48 to the inlet of pump 49 from which it passes through pipe 52 to the 'coil 1 which acts as a cooling coil.

acts to precool the incoming air. The water.

leaving coil 6 then flows through pipe 39, valve 32, and pipe 49 tothe condenser coil I3 for thereby cooling the refrigerant compressed by the compressor. The water'in passing through the condenser becomes heated and flows through valve 42 to the valve 44 which divides this stream between the storage tank 46 and the waste pipe I95 to position the valve 44 for passing all of the water flowing through pipe 43 into the tank 46. Deenergization of the relay 16 will cause the summer thermostat to be disconnected from the step controller motor 69 and to place this motor under the -control of the winter space thermostat 12 and the discharge thermostat 13. However, due to the opening of switch 93 or stepcontroller 61 at this time, the relays 5I and 14 will be deenergized and the compressor 8 and the circulating pump 49 will not be in operation. With outside temperature at this value, no conditioning is necessary for the space and until outside temperature falls to approximately 60 F., no heating will be necessary.

When outside temperature falls to 60 F., the mercury switch 92 will close which will energize the pump starter 5| for placing the pump 49 into 58. At this time, it will be noted that the relay 16 is deenergized which acts to place the pressure controller 15 in control of the motor. I95 which positions the three-way valve 44. Thus when the pressure within tank 46 is at the predetermined value, such as 40* pounds per square inch, the valve 44 assumes the position shown which causes all of the water leaving condenser coil I3 to pass through the waste pipe 58 to the sump38 from which it flows through the subterranean ditch 39 back to the well 28. As the pressure within tank 46 lowers, the motor I95 will position valve 44 for permitting flow of a portion of the water into tank 46.

With the mercury switch 3| in the position shown, the relay 10 is energized which acts to place the compressor stencontroller under the control of the summer thermostat 1|. This thermostat acts to increase the compressor speed as the space temperature increases to thereby vary the refrigeration in accordance with the cooling load upon the system.

The thermostat 11 which is responsive to the temperature of the water in tank 46 will control the-valve 42 in a manner to close valve 42 progressively with decrease in temperaturewithin tank 46; This restriction of the water flow causes the water to be heatedto a higher temperature as it flows through the condenser I2 and thus provides for maintaining the water in tank 46 at the desired temperature. With the timer in the position shown, the low temperature potentiometer 226 is connected into the control circuit of motor 208 which causes the thermostat 11 to maintain the tank temperature at the desired normal value. As the peak load period for the power service approaches, the cam 229 will tilt mercury switch 23 I to its opposite position for operationand will also energize the compressor relay 14 for permitting operation of the compressor under the control of the winter space thermostat 12 and the discharge thermostat 13. These thermostats will then operate to control the speed of the compressor in a manner to prevent the space temperature from falling below the setting of thermostat 12 and to prevent the discharge temperature from falling 'below the setting of discharge thermostat 13.

At this time, the

S valves

32, 36, and 56 will be deenergized and the W valves 3|, 35, and 51 will be energized through the mercury switch 92. Due to. valves 3i, 35, and 51 being opened, water will flow from the coil 1 through pipes 53 and 55 to valve 51, then through pipe 46 to coil I3 of condenser I2 wherein it is heated. This now placing the high temperature potentiometer 225 into the motor control circuit thereby causing the tank water temperature to be increased for thereby storing up additional heat. When the peak load period occurs, the mercury switch 232 of the timer 18 will be opened which acts to deenergize the compressor relay 14 thereby placing the compressor out of operation.

When outside temperature falls below 75 F the mercury switch 9| of the step controller 61 will tilt to its opposite position which acts to energize the relay I6 and to dleenergize the relay 10. Energization of the relay 16 will disconnect the pressure controller 15 from the three-way valve motor I95 and connect this pressure controller to the city water supplyvalve motor 6|. Energization of this relay will also cause motor heated water will then flow through the throttling valve 42 to the three-way valve 44 which will now be positioned for passing all of this water to tank 46. Water will then flow from this tank through the circulating pipe 41 and pipe 46 to the pump 49 which discharges this hot Water through the pipe 52 to the coil 1. Also, the pump 25 will withdraw water from well 28 passing it through the coil 6 which acts as a preheater, this water then passing through pipe 30, valve 3|, and pipe 33 to coil I8 in the evaporator I1 and through pipe 34, valve 35, and pipe 31 to the sump 38. Therefore when the system is operating on the heating cycle, the coil 1 receives hot water from the storage tank 46 which in turn is heated by the condenser I2. Also, the well water after preheating the air passes through the evaporator I1 for thus providing a source of heat for the refrigeration system.

During the heating cycle, the thermostat 11 will control the throttling valve 42 just as it does during the cooling cycle. Also, the timer 18 will act to stop the compressor during peak load periods and to raise the water temperature in,

tank 46 prior to these peak load periods for thereby storing up heat for use during the, peak load It should be noted that the timer 18 stops only the compressor and permits the circulating pump 50 to continue to operate for thereby supplying heat to the space even when the compressor is not operating.

From the foregoing description, it will be apparent that this invention has provided a system for heating andcooling a space by means of a refrigeration system, the system being caused to selectively heat or cool by changing the water piping connections, thereby permitting the refrigeration system to operate in the same manner at all times. It will also be apparent that this invention provid% an automatically conditions both in summer and in winter and for also maintaining a supply of domestic hot water..

While throughout this description definite values of temperature and pressure have been mentioned for illustrative purposes, it will be apparent that these values may be varied as desired for different installations and applications of this invention. Also, while I have shown but one embodiment of this invention, the invention is not limited to the speciflcarrangement illustrated. As many modifications of the system which are within the scope of the invention will be apparent to those skilled in the art, I desire to be limited only by the scope of the appended I claim as my invention:

1. In a reversible cycle system for heating or cooling a space, in'combination, a refrigeration system having an evaporator, a condenser and a compressor, a heat exchanger in heat exchange relationship with said space,' fluid conveying means including valve means for selectively com I necting said heat exchanger into fluid circulating relationship with said evaporator or saidcondenser, thermostatic means for controlling said compressor, changeover means for controlling said valve means and also controlling said thermostatic means in a manner to cause said thermostatic means to start said compressor upon fall in temperature when said heat exchanger is connected to said condenser and to start said compressor upon rise in temperature when said heat exchanger is connected to said evaporator, and outside temperature responsive means for controlling said changeover means and for pre-' venting operation of said compressor when out-- side temperature is between predetermined values.

2. In a reversible cycle system forheating and cooling 8. space, in combination, a refrigeration system having an evaporator device, a condenser device and a compressor, a heat exchanger in heat exchange relationship with said space, a

storage tank, fluid conveying meansincluding valve means for selectively connecting said heat exchanger into fluid circulating relationship with said evaporator device or said condenser device while maintaining said storage tank connected for receiving fluid from one of said devices, thermostatic means for controlling said compressor, changeover means for controlling said valve means and also controlling said thermostatic means in a manner to cause said thermostatic means to start said compressor upon fall in temperature when said heat exchanger is connected to said condenser device and to start said compressor upon'rise'in temperature when said heat exchanger is connected to said evaporator device, and means for controlling the temperature in said storage tank.

. 3. In a reversible cycle system for heating and cooling, in combination, a refrigeration system having an evaporator device and a condenserdevice, a heat exchanger in heat exchange relationship with a medium to be conditioned. a

ustorage tank for fluid, means for selectively connecting said heat exchanger into fluid circulating relationship with either said evaporator device or condenser device while maintaining said stor-. age tank connected for receiving fluid from one of said devices, a flow controller for controlling the flow. of fluid through said one device, and means responsive to the temperature of the fluid for controlling said flow controller.

4. In a reversible cycle system for heating and cooling, in combination, a refrigeration system having an evaporator device and a condenser device, a heat exchanger in heat exchange relationship with a medium to be conditioned, a storage tankfor fluid, means for selectively connecting said heat exchanger into fluid circulating relationship with either said evaporator device or condenser device while maintaining said storage tank connected for receiving fluid from one of said devices, flow control means for controlling the flow of fluid into saidstorage tank, and means responsive to the temperature of the fluid in said storage tank for"'controlling said flow control means.

5. 'In a reversible cycle system for heating and cooling, in combination, a refrigeration system having an evaporator device and a condenser device, a heat exchanger in heat exchange relationship with a medium to. be conditioned, a storage tank for fluid, means for selectively connecting said heat exchanger into fluid circulating relationship with either said evaporator device or condenser device while maintaining said storage tank connected for receiving fluid fromv one of said devices, a flow controller. for controlling the flow of fluid through said one device, means responsive to the temperature of the fluid for controlling said flow controller, flow control means for controlling the flow of fluid into said storage tank, and meansresponsive to the quantity of fluid in said storage tank for controlling I said flow control means.

6. In a reversible cycle system for heating and cooling, in combination, a refrigeration system having an evaporator device and a condenser device, a heat. exchanger in heat exchange relationship with a medium to be conditioned, a

storage tank for fluid, means for selectively con- I necting said heat exchanger into fluid circulating relationship with either said evaporator device or said condenser device while maintaining said storage tank connected for receiving fluid from one of said devices, temperature respon-' sive means for controlling said refrigeration system, temperature responsive means for controlling the temperature in said storage tank, and timing means for varying the temperaturejmain tained in said storage tank and thereafter preventing operation of said refrigeration system.

7. In a reversible cycle system for heating and cooling, in combination, a refrigeration system, means adapted to either heat or cool a space and including a storage tank for conditioning medium which is changed in temperature by the refrigeration system, thermostatic means respontive to the temperature of the stored medium for controlling the temperature of said medium, timing means for limiting operation of said refrigeration system for predetermined periods, and means actuated by said timing means forvarying. the temperature of the stored medium prior to said periods.

8. In a reversible cycle system for heating and cooling, in combination, a refrigeration system,

v means adapted to either heat or cool a-space and including a storage tank for conditioning medium which is changed in temperature by the refrigeration system, .a circulating pump for circulating the conditioning medium, temperature responsive means for controlling the circulating pump, thermostatic means for controlling the perature of the stored medium, timing means for limiting the operation of said refrigeration system during predetermined periods while permitting said circulating pump to operate, and means actuated by the timing means for varyin the temperature of the stored medium prior to said periods. I V

9. In a system of the class described, in combination, a refrigeration system, means for conditioning a space, said refrigeration system including a compressor, a storage tank for storing conditioning medium which is changed in temperature by said refrigeration system, a circulating pump for circulating conditioning medium between said tank and said conditioning means, temperature responsive means for controlling said compressor and circulating Pump, and timing means for limiting theoperation of said compressor during predetermined periods while permitting said circulating pump to continue to operate under the control of said temperature responsive means.

10. In a system for conditioning the air in a space, in combination, a refrigeration system for changing the heat content of the air in said space, a storage tank for medium which is changed in temperature changing capacity by said refrigeration system, thermostatic means for controlling the temperature changing capacityof the medium in said storage tank, timing condenser to said heat exchanger and a second position causing heat transfer fluid to circulate from said evaporator to said heat exchanger,

' thermostatic means for controlling the power means for'placing the refrigeration system out of operation during predetermined periods, and means controlled by said timing means-for adlusting said thermostatic means prior to said periods in such manner that the temperature changing capacity of said medium is increased.

11. In a system for conditioning a space, in combination, a heat exchanger in heat exchange relationship with said space, a storage tank for heat exchange medium, piping means for' circulating heat exchange medium from said storage tank through said heat exchanger, thermostatic means for controlling the circulation of heat exchange medium, a power consuming means for changing the temperature of the medium in said storage tank, thermostatic means responsive to the temperature of said medium for controlling said power consuming means for maintaining said medium at a predetermined temperature so thatlt has a predetermined heat exchange capacity, timingmeans for placing said powerconsuming means out of operation during predetermined periods, and -means controlled by said timing means for adjusting said thermostatic means prior to said periods in such" a manner as to increase the heat exchange capacity above said predetermined capacity. l

12-. In a reversible refrigeration system for heating or cooling a space, in combination, a conditioning chamber through which air is passed to said space, a heat exchanger in said chamber, a refrigeration system having an evaporator and a condenser, piping means between said heat exchangerfievaporator, and condenser,

' circulation controlling means, two-position type control means for said circulation controlling means, said control means having a first position causing heat transfer fluid to circulate from said inputto said refrigerationsystem, a low limit thermostat responsive to the temperature of. the air discharged from said heat exchanger for controlling the power input in a manner to prevent the discharge air temperature from falling below a predetermined value, and changeover means for actuating said control means to reverse the system fromheating to cooling, said changeover also controlling the action of said thermostatic means and of said low limit thermostat to cause said thermostatic means to operate on temperature rise and to render said low limit thermostat ineffective to prevent the temperature of the discharge of air from falling below said predetermined value when the control means is operated to place the system on cooling.

13. An apparatus for serially utilizing'a single supply of water for both heat exchange and a second water using system, said apparatus comprising aheat exchanger, a line connected to said single supply of water for continuously supplying water therefrom to the heat exchanger, a

1 second line from the outlet of said heat exwater supply in excess of the requirements of said secondwater using system while maintaining-said second water using system under ade'-'- quate pressure.

14. An apparatus for serially utilizing a single supply of water for both heat exchange and domestic use, said apparatus comprising a heat exchanger, a line connected to said single supply of water for continuously supplying water therefrom to the heat exchanger, a second line from the outlet of said heat exchanger connecting with a domestic water supply, a modulating valve in one of said lines for controlling the flow of water through the heat exchanger, thermostatic means for automatically controlling said modulating valve in accordance with the temperature of the water in said apparatus, and valve means operated in response to pressure in the apparatus which permits continued fiow of water from said single source of 'si pply through said heat exchanger and diverts that portion of the water flowing through the heat exchanger from the single water supply which is not needed in said domestic water supply while maintaining said domestic water supply under adequate pressure.

' ROBERT B. P. CRAWFORD.