US3774234A

US3774234A - Servicing apparatus for heating/cooling systems

Info

Publication number: US3774234A
Application number: US00263151A
Authority: US
Inventors: R Blair
Original assignee: Individual
Current assignee: Individual
Priority date: 1972-06-15
Filing date: 1972-06-15
Publication date: 1973-11-20
Anticipated expiration: 1990-11-20

Abstract

A portable servicing apparatus for operating heating/cooling systems through various stages of operation while allowing the user to simultaneously observe the operation of the components of the system includes a plurality of electrical leads adapted to be coupled to a terminal board of the unit being serviced or tested. A power supply in the apparatus provides 110/220 volt alternating current or 24 volt alternating current power to the various leads in a predetermined and selectable manner that can be controlled by a plurality of switches to actuate the system components. Each switch includes an indicator light associated therewith to indicate to the user the stage of the system under test or the component which is actuated by the serving apparatus. Means are included for determining the proper operation of the indicator lamps to insure that an accurate indication is provided by the servicing apparatus.

Description

United States Patent [191% Blair n 3,774,234 [451 Nov. 20, 1973 SERVICING APPARATUS FOR HEATING/COOLING SYSTEMS Primary ExaminerHerman J. Hohauser Att0rn eyPeter P. Price et al.

[5 7 ABSTRACT A portable servicing apparatus for operating heating- /cooling systems through various stages of operation while allowing the userto simultaneously observe the operation of the components of the system includes a plurality of electrical leads adapted-to be coupled to a terminal board of the unit being serviced or tested. A power supply in the apparatus provides 110/220 volt alternating current or 24 volt alternating current power to the various leads in a predetermined and selectable manner that can be controlled by a plurality of switches to actuate the system components. Each.

switch includes an indicator light associated therewith to indicate to the user the stage of the system under test or the component which is actuated by the serving apparatus. Means are included for determining the proper operation of the indicator lamps to insure thatv an accurate indication is provided by the servicing apparatus.

11 Claims, 4 Drawing Figures LOW VOLTAGE SIDE SYST EM TEST 24 VOLT SWITCH 24 VOLT COMMON IN POWER STAGE l STAGE 2 CHANGE HEAT HEAT .OVER

DAMPER T0 CONTROLS TRANSFORMS.

HEATlNG COOUNG was as"? a 65 m 12 OFF OFF OFF co R L ON 0L OFF OFF OFF OFF JACK. v

. 0 ON 64 ON ON ON ON ON I ON 77 z4vou uvou' POWER 7 ea RED mu: GREEN I want LtGHT new A 11 1s 1s coou Ne I HEATING POWER COOLING I RED 3 near I I I65 151 l 113 \15 on on I ON 0N on OFF or; 16s on HEATING coouue 18o HOV OR 320v JACK /l JACK l 2 I l I LINE VOLTAGE a 220 on uov mm SWITCH at aaoonuov \NTERVAL 24 VOLT AMBER LIGHT ll0 VOLT INPUT STAGEI STAGE 2 FAN COOUNG COOLlNG CHANGE in I74 W B on: or: or;

' T0 comao Ls LINE VOLTAGE SIDE PATENTEUNBVaoma 3,714,234

SHEET 2 CF 4 LOW VOLTAGE SlDE SY'ST EM NT ERVAL TEST 24 VOLT 24 VOLT AMBER SWITCH TRANSFORMER uem 55 no VOLT 22o vou \NPUT m PUT 24 von v I common 63 HEATNG COOUNG 24 VOLT TO 24VOLT T0 68 7o 12 74 s T 5 OFF OFF OFF CONTROL CON OFF on OFF OFF 0 ON G3 ON 64 N 68 ON 80 90 ON ON ON BLUE L RED BLUE GREEN 24 VOLT 24 VOLT HEATING PWER POWER COOLING STAGE! STAGEZ CHANGE cumes STAGEl STAGE 2 FAN HEAT HEAT oven oven COOLING coouue DAMPER DAMPER no OR 220 VOLT i v I HEATTNG POWER COOLING CLEAR CLEAR R RED uem usm uem uem 7 [64 I'll ON ON ON ON no ON "2 ON 74 ON Mil Q l68 B OFF OFF OFF 166 OFF OFF OFF OFF I64 on y I HEATING I29 I coouN 13o HOV 0R 220V mew/M E JACK l I I22 POWER I l 220 OR uov kw, Q'W GEE I U 220 OR uov TO CONTROLS C T0 CONTROLS UNE' VOLTAGE SIDE FIG. 2

Pmminunvz w 5,774,234

SHEET 4 [1F 4 COOKING SAFTY COOLlNG SAFTY FAN RELAY RELAY CONTROlSl RELAY a comm! ROOM MR 1 v I 242 24-5 v 260 HEATING I HEATING 0- SW35 l STAGE 2 ans coMEusnou F f\N GAS VALVE GAS VALVE 5 FAN RELAY 5 AT THERMACOUPLE LEAD COMBUSTION 24v SECONDARY IGN'TOR TRANS- FORMER AND- 1 I THERMACOUPLE SAFTI SWITCH m uov PFUMARI iNTERNAL GROUND TERMINAL IGNITIOR LEAD E x r\ A L v R. zoo 0R 0 Y! 0 I2 owl o W 2 0B COMBUS'flX 0G 24 von COOL COOL 2 HEAT I HEAT 2 TION BLOWER 24v common: FAN

212% -zle e06 2oa- 33 YELLOW BLUE WHITE GREEN we YELLOW WHITE RED 1 SERVICING UNIT TERMINAL BOARD FIG. 4

SERVICING APPARATUS FOR HEATING/COOLING SYSTEMS BACKGROUND OF THE INVENTION The present invention relates to a portable servicing 5 apparatus for heating/cooling systems, and more particularly to an apparatus for controllingheating/cooling units through various stages of heating and cooling cycles of operation.

Presently, commercial buildings such as shopping malls, retail stores and offices are frequently of oneor two-level construction with the heating and cooling systems located on rooftops and the thermostatic controls located within the building. Also, many older buildings such as factories, hospitals and the like have been con- I verted to employ modern heating/cooling systems of this type or split systems. Although these units are relatively inexpensive, easy to install and do not reduce the usable space of the building; the servicing of such units is relatively difficult.

The units are almost always physically positioned at a different level than the controls which are employed to operate them. In split systems, the heating unit may be in a basement while the cooling unit is on a rooftop. To service the units, it is frequently necessary to cycle the heating/cooling units through four or five cycles of operation and make repairs or adjustments to individual components of the system between the various cycles. One method to achieve the servicing is to adjust the remotely positioned thermostat to operate the unit through the desired cycle and return to the unit to observe the operation. This procedure is very time consuming and difficult or practically impossible particularly when, as is the usual case, only one serviceman is available for the maintenance of the unit.

In some systems it is possible to short out or disconnect the leads from the thermostat which connect to the unit at an interface terminal board and thereby partially overcome the difficulty by jury rigging the unit. Such an approach however, has not proven useful in cycling complex heating/cooling'units through all of the various stages of operation of a heating or a cooling cycle or both.

Also, in many installations, different voltages are employed to operate the various system components. These systems cannot easily be tested or run through the various stages of the heating and cooling cycles by employing previously used techniques. Thus, with the recent proliferation of modern complex heating/cooling systems, a need exists for a servicing apparatus which can be used by a single person for operating the heating/cooling system at thesitus of the system.

SUMMARY OF THE INVENTION The apparatus of the present invention overcomes the difficulty of servicing heating/cooling units by providing a portable servicing instrument which can be coupled to the thermostat interface terminal board on the heating/cooling unit. The instrument is operable to power preselected controls of the unit under test to cycle the system through desired stages of the heating or cooling cycles ,of operation. Additionally, with this apparatus it is possible to operate the heating and cooling cycles simultaneously or in any desired sequence for observing the functioning of various elements of the system during operation. t

Apparatus embodying the present invention comprises a portable servicing instrument for providing first and second control voltages to preselected electrical leads which can be directly coupled to the unit under test. The voltage applied to the various electrical leads is controlled by switching means which simultaneously actuate indicator lights associated with each lead such that a visual indication is presented as to which lead and therefore what element of the heating/cooling system is being actuated. Means are provided for testing the continuity of various of the indicator lights prior to using the instrument to insure its proper operation.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of the servicing apparatus 0f the present invention;

FIG. 2 is an enlarged view of the control panel of the apparatus of the present invention;

FIG. 3 is an electrical circuit diagram in schematic form of the servicing apparatus; and

FIG. 4 is an electrical circuit diagram partially in schematic and block diagram form illustrating the interconnection of the servicing apparatus of the present invention with a heating/cooling system.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now in detail to FIG. 1, there is shown the servicing instrument of the present invention which includes a portable carrying case 10 comprising a rectangular container 12 in which the electrical components are mounted, and a hinged cover 16. The case 10 includes a handle 15 for carrying the instrument and a fastener 17 for holding the cover in a closed position. A control panel 50 mounted to the container holds the various controls and indicators for the instrument in an array as shown in detail in FIG. 2. A storage receptacle 18 is provided in the container for holding the electrical leads when the instrument is not in use. The leads include a multiple conductor power input cord 20, a pair of multiple conductor first leads 30, 30' and a pair of multiple conductor second leads 40, 40'.

, Each electrical conductor of each of the

leads

30, 30, 40 and 40' has a distinguishing .color for the purpose described below. Additionally, each of the leads has a plug at one end adapted to be inserted into a corresponding jack on control panel 50. Opposite ends of the leads have alligator clips, lugs or other suitable connjecting means 35. When not in use, these leads can be stored in the compartment 18 and the hinged cover is closed and fastened to provide a compact unit for transportation.

Referring now to FIGS. 2 and 3 which slow the control panel and circuits for the servicing apparatus, it is seen that the panelSO is divided into upper and lower sections A and B for 24 volt operation and 1 10 or 220 volt operation respectively of the heating/cooling unit being serviced. On the 24 volt side, a first series of

switches

62, 64, 66, 68, 70, 72 and 74 each have a terminal a commonly coupled to a bus line 61 which is coupled to a first terminal 155 of a power supply 150 by means of a switch 130. A terminal b of each of these switches 62 through 74 is coupled to first terminals 1410 through 147a respectively or a relay 140. Second terminals l41b through 147b' of relay contacts 141 through 147 are coupled to output heating and cooling jacks and respectively. Terminal 14lb of relay 140 is coupled to terminal 91 of cooling jack 90, contact 142b of relay 140 is coupled to terminal 92 of jack 90, and so forth; each relay terminal being coupled to a jack terminal having the same final digit in the identifying reference numeral.

Terminals

88 and 98 of

jacks

80 and 90 are coupled to switch 130 to receive power from the unit under test if desired. With the switch 130 in the position shown, power is supplied by power supply 150.

Relay 140 includes arelay coil 148 having a first terminal 149a coupled to the output terminal 155 of the power supply 150 by means of a push button switch 135 and switch 130 as described below. A second terminal 149b associated with the relay coil 148 is coupled directly to a terminal 157 of power supply 150. The relay is a normally closed relay such that unless push button switch 135 has been actuated to energize the relay and open contacts 141 through 147, the actuation of one of the switches 62 through 74 will cause the associated one of the output terminals of the heating or

cooling jacks

80 or 90 to become actuated by the power applied from output terminal 155 of the power supply and a common output terminal 159 which is coupled to the output terminal 157 of the power supply by means of a fuse 158.

Each of the second switch terminals 62b through 74b is additionally coupled to a first terminal of each of the

indicator lamps

63, 65, 67, 69, 71, 73, and 75 associated with and positioned below the switches respectively at a terminal a of each of the indicator lights as shown. A second terminal b of each of the indicator lights is coupled directly to terminal 157 of the power supply. Indicator lights 77 and 78 are coupled in parallel between terminal 157 and the bus 61 which commonly couples terminals a of the first series of switches.

Each lamp associated with a switch has a colored lens 63 through 75' (FIG. 2) and the output lead conductors in

leads

30 or 40 are colored such that when a switch is actuated, power from

terminals

155 and 157 of the power supply will be applied to the conductor colored to correspond to the same colored indicator light thereby providing an indication to the user that the conductor is actuated. Under each of the lenses 62 through 74 there is placed suitable labeling (FIG. 2) to identify what particular function the switch has been assigned thereby facilitating the use of the instrument for operating the unit under test through the various stages of heating and/or cooling cycles of operation. Thus for example, the lens 63' will be associated with stage one heating, is white and has a white conductor while the change-over damper control is a blue lens 67' which is associated with switch 66 such that when this switch is actuated, a blue conductor in lead 30 that is coupled to the change-over damper of the unit as described below will be actuated and indicated by the illumination of lamp 67 below lens 67'.

Similarly, on the cooling side of the first series of switches the lenses 69' through 75' are blue, yellow, white and green respectively and are associated with the change-over damper stage one cooling, stage two cooling and fan control similarly colored and coupled to the cooling output jack 90.

The power switch 130 is a double-pole double-throw type of switch which, when in its internal power position as illustrated in the figure, applies 24 volt power from the power supply to the bus line 61 as well as to terminal 136 of push button switch 135. Switch 135 is provided to actuate relay 140 such that the indicator lights 63 through can be checked to see if they are operational without actuating the heating/cooling unit while the instrument is coupled to the unit. This is accomplished by first depressing push button 135 which disconnects output jacks and since relay contacts 141 through 147 open, and then switching the indicator light switches to their on position to ascertain whether or not they are illuminated and therefore good. If all the bulbs are operational, the switches can be opened again and push button switch released to couple the switches to the

jacks

80 and 90. In some embodiments, the push button switch 135 can be replaced with a toggle switch although the spring-loaded push button switch is preferable.

The power supply which couples 24 volt alternating current to first voltage output terminals and 157, comprises a step-down transformer 100 having

primary windings

102 and 104 and a secondary winding 106 which has output terminals coupled to

output terminals

155 and 157 of the power supply. This transformer is adapted for

l

10 or 220 volt operation by virtue of the split primary winding and the selected position of a four-pole double-throw switch 120. When in the 1 10 volt position as shown in the figure, switch 120 couples the primary windings 102and 104 in parallel. In the 220 volt position, the primary windings are in series to provide-24 volt alternating current across the secondary.

Means for applying 110 volt or 220 volt power to the power supply 150 includes a power input jack 122 to which the power lead 20 (FIG. 1) is coupled. Jack 122 has

output terminals

125 and 126 coupled to fuses 128 and to terminals of the double-pole single-throw power on-off switch 129. A 220 volt indicator lamp 137 is coupled across the

output terminals

131 and 132 of switch 129 to indicate when the switch is actuated, and a l 10 volt indicator light 138 is coupled from terminal 131 of the switch to terminal 127 of the input jack 122 to indicate when 1 10 volt power is being supplied to the apparatus.

Terminals

131 and 132 serve as second voltage (1 10/220) output terminals for power supply 150.

A bus line 161 is coupled to terminal 131 of switch 129 and to one terminal (terminal a) of a series of indicator lamps 163 through associated with a second series of switches 162 through 174 respectively. The switches each have a first terminal a commonly coupled to terminal 132 of switch 129 and a second termi nal b coupled to a corresponding terminal on heating- /cooling jacks and respectively. Thus, terminal 162b of switch 162 is coupled to terminal 182 of jack 180 and so on; each switch being coupled to a jack terminal having the same last numeral in its identifying reference character.

Additionally, each of the second terminals b of each of the switches 162 through 174 is coupled to a terminal b on its corresponding indicating lamp 173 through 175 by means of a series coupled current limiting resistor 162 through 174'. With this arrangement, the indicator lights, which are neon bulbs, can be used for both 1 10 volt and 220 volt operation without damaging the lights. As with the 24 volt side of the control panel, the 1 10/220 volt, section B has a series of lenses 163' -through 175' which have a color corresponding to the color of the electrical conductor of output lead 40 which is coupled to the individual switch through the

jacks

180 and 190. An indicator light 178 and series resistor 178' are coupled between the bus line 161 and the output terminal 132 of switch 129 to indicate when power is applied to the switches of section B.

Having described the construction of the servicing time move into position to observe the operation of the instrument, a brief description of its use together with a two-stage heating and two-stage cooling rooftop heating/cooling apparatus is described in conjunction with FIG. 4. l

Initially, it is noted that each heating/cooling unit will have a terminal board 200 with a pluality of terminals usually labeled with standard reference characters. The reference numerals are shown on the terminal board 200 while the description of the component within the system to which the terminal board is coupled is shown below the terminal board 200 in FIG. 4. With the system shown, it is necessary to disconnect terminals r and g from the existing unit control when using the servicing apparatus. If the systems 24 volt power is to be employed, a red lead 202 is coupledto terminal r on terminal board 200 and switch 130 is positioned in its system 24 volt position (opposite that shown in FIG. 3). Lead 202 is coupled to pin 88 of

jack

80 and 98 of jack 90. Similarly, a 24-volt common lead 204 which may be a white lead, is coupled between jack 159 on the servicing apparatus and terminal x of the terminal board 200. These connections are made regardless of whether internal or external power is employed. If the servicing apparatus is to supply the operating voltage, its power lead is coupled to a suitable 1 or 220 volt supply and switch 120 is appropriately positioned to provide 24 volt output when swich 130 is switched into its position shown in FIG. 3.

Once the desired operating power source has been coupled and the power switches positioned in their desired condition, the first series of switches are positioned in their off position and the remaining leads are coupled to the remaining terminals on terminal board 200. Thus, the yellow lead 206 associated with switch 70 and stage-one cooling is coupled to Y-l of the terminal board; white lead 208 associated with switch 72 is coupled to the Y -2 stage-two cooling terminal of the board 200. White lead 210 associated with switch 62 is coupled to W-l of the terminal board and yellow lead 212 associated with switch 64 is coupled to the W-2 terminal of the board. Finally, the blue lead 214 associated with switch 66 is coupled to terminal B of the board and the green lead 216 associated with switch 74 is coupled to the G terminal of board 200. It is noted here that since the

lead

20, 30, 30, 40 and 40' (FIG. 1) are associated with separate plugs for the heating, cooling and

power jacks

80, 90, 180, 190 and 122 respectively; thesame colors can be used for each of the leads without confusion. It is noted however, that each of the leads can be uniquely colored or have colored tracers if desired.

Once connected, the operator first depresses the momentary push button switch 135 to test the indicator lights by switching each light temporarily into its on position to see if it illuminates. Once this has been completed, the push button 135 is released and the apparatus is ready to be used for checking the heating/cooling unit.

Initially, it may be desired to check the ignitor for proper operation. To do this, switch 66 is actuated to provide power to an ignition transformer 230 via blue conductor 214. The light 67 will be actuated to illuminate blue lens 67 thereby indicating that the ignitor is actuated. The user of the servicing apparatus can at this ignitor and make any necessary adjustments. Stage-one heating can then be actuated by actuating switch 62 which activates the first stage heating controls 240, 242 and 243 via white conductor 210. Again, the user can observe the heating valve and associated apparatus for proper operation. Similarly, the second stage heating unit 245 can be actuated by moving switch 64 to its Q! ',1P9 i9-.

In the same manner, the first and second stage cooling controls 250, 252, 254 and 256 can be actuated by moving

switches

71 and 72 respectively to the on" position and observing the cooling controls. The fan controls 258 and 260 likewise can be actuated by moving switch 74 to its on" position thereby actuating lead 216 to apply power to the fan controls.

invention, any combination of the various operational uhits of the heating/cooling unit can be sequentially or simultaneously actuated for any desired length of time to allow the servicing personnel to check the operation of these units. With this apparatus, it is possible to simultaneously operate the heating and cooling units for checking the various controls without severely changing the temperature of the rooms serviced by the unit being tested. Likewise, any of the units can be run intermittently or continuously in a manner necessary for maimsas ss repair- It will become apparent to those skilled in the art that various modifications to the apparatus embodying the present invention can be made without departing from the spirit or scope of the present invention as defined i ihsirzasa claims- What is claimed is:

l. A portable servicing apparatus for providing electrical power to various components of a heating/cooling system comprising:

power supply means for supplying a first voltage. at first output terminals thereof and a second voltage at second voltage output terminals thereof;

means for applying operating power to said power supply means;

a first series of switches each having first and second terminals, wherein said first terminals are coupled to one of said first terminals of said power supply means;

a second series of switches each having first and second terminals, wherein said first terminals are coupled to one of said second terminals of said second output terminals of said power supply means;

a plurality of electrical output leads;

means for individually coupling said output leads to said second terminals of said first and second series of switches such that an output lead is associated with each switch;

a plurality of indicator lights, each coupled to said second terminal of a predetermined one of said first or second switches to be associated therewith, said lights further coupled to said power supply means to be actuated when the associated switch is actuated to apply voltage from said power supply 7 means to an associated lead whereby the voltage applied to said associated output lead activates said associated indicator light.

2..The apparatus as defined in claim 1 wherein said apparatus includes a control panel to which said first and second series of switches are mounted wherein said panel includes indicia identifying a unique function for each switch wherein at least one switch of said first series of switches is coupled to an output lead for actuating a heating component of the heating/cooling unit under test.

3. The apparatus as defined in claim 2 wherein said first series of switches includes at least one switch coupled to an output lead for actuating a cooling component of the unit under test.

4. The apparatus as defined in claim 1 wherein said apparatus includes a control panel to which said first and second series of switches are mounted and said panel includes indicia identifying a unique function for each switch wherein at least one switch of said second series of switches is associated with a lead for actuating a heating component of the heating/cooling unit under test, and at least another switch is associated with a lead for actuating a cooling component of the heating- /cooling unit under test.

5. The apparatus as defined in claim 4 and further including a multiple contact relay having a plurality of relay contacts, each relay contact coupled in series between said second terminal of one of said first series of switches and an associated output lead, and means for actuating said relay to open said relay contacts.

6. The apparatus as defined in claim 5 wherein said means for actuating said relay comprises a momentary push button switch coupled between a relay coil associated with said relay and said power supply means.

7. The apparatus as defined in claim 6 wherein each output lead has a predetermined color and each indicator light has a lens colored to match the color of the lead associated therewith.

8. A portable servicing apparatus for selectively controlling electrically operated components in a heating- /cooling system comprising:

means for receiving operating power for said apparatus,

a step-down transformer having primary and secondary windings for providing a lowered alternating current output voltage across said secondary winding in response to line voltage applied to said primary winding from said receiving means,

a first series of switches having first and second terminals electrically coupled to one another when said switches are in a closed position,

means for coupling said secondary winding to said first terminal of said first series of switches,

a plug including a plurality of color coded output conductors,

at least one output jack mounted to the apparatus and adapted to receive said plug,

means coupling terminals of said at least one output jack to said second terminals of predetermined ones of said switches, and

a first series of indicator lights coupled to said second terminals of each of said switches to be actuated when said switch is actuated to apply power to an associated output conductor, said lights including color coded lenses corresponding to said color coded output conductors coupled thereto.

9. The apparatus as defined in claim 8 and further including a, second series of switches, each having first and second terminals electrically coupled to one another when the switch is in a closed position wherein a first terminal of each of said second switches are coupled to said primary winding of said transformer,

a second output jack adapted to receive a second plug having a plurality of second color coded conductors coupled thereto, said output jack having a plurality of terminals coupled to corresponding second terminals of said second series of switches, and

a second series of indicator lights coupled to said second terminals of each of said second series of switches to be actuated when said corresponding switch is actuated to apply power to an associated output conductor, said second series of lights including color coded lenses' corresponding to said second color coded conductors coupled thereto.

10. The apparatus as defined in claim 9 wherein said means coupling said terminals of said first switches to saidat least one output jack includes a plurality of normally closed relay contacts, each contact being coupled in series between a switch and a corresponding terminal of said at least one output jack, and

means for actuating said relay to open said contacts to disconnect said terminals of said output jack from said switches.

1 l. The apparatus as defined in claim 10 wherein said transformer, said first and second series of switches and lights, and said output jacks are positioned in a container having a storage area for output conductors and a hinged cover.

Claims

1. A portable servicing apparatus for providing electrical power to various components of a heating/cooling system comprising: power supply means for supplying a first voltage at first output terminals thereof and a second voltage at second voltage output terminals thereof; means for applying operating power to said power supply means; a first series of switches each having first and second terminals, wherein said first terminals are coupled to one of said first terminals of said power supply means; a second series of switches each having first and second terminals, wherein said first terminals are coupled to one of said second terminals of said second output terminals of said power supply means; a plurality of electrical output leads; means for individually coupling said output leads to said second terminals of said first and second series of switches such that an output lead is associated with each switch; a plurality of indicator lights, each coupled to said second terminal of a predetermined one of said first or second switches to be associated therewith, said lights further coupled to said power supply means to be actuated when the associated switch is actuated to apply voltage from said power supply means to an associated lead whereby the voltage applied to said associated output lead activates said associated indicator light.

2. The apparatus as defined in claim 1 wherein said apparatus includes a control panel to which said first and second series of switches are mounted wherein said panel includes indicia identifying a unique function for each switch wherein at least one switch of said first series of switches is coupled to an output lead for actuating a heating component of the heating/cooling unit under test.

4. The apparatus as defined in claim 1 wherein said apparatus includes a control panel to which said first and second series of switches are mounted and said panel includes indicia identifying a unique function for each switch wherein at least one switch of said second series of switches is associated with a lead for actuating a heating component of the heating/cooling unit under test, and at least another switch is associated with a lead for actuating a cooling component of the heating/cooling unit under test.

8. A portable servicing apparatus for selectively controlling electrically operated components in a heating/cooling system comprising: means for receiving operating power for said apparatus, a step-down transFormer having primary and secondary windings for providing a lowered alternating current output voltage across said secondary winding in response to line voltage applied to said primary winding from said receiving means, a first series of switches having first and second terminals electrically coupled to one another when said switches are in a closed position, means for coupling said secondary winding to said first terminal of said first series of switches, a plug including a plurality of color coded output conductors, at least one output jack mounted to the apparatus and adapted to receive said plug, means coupling terminals of said at least one output jack to said second terminals of predetermined ones of said switches, and a first series of indicator lights coupled to said second terminals of each of said switches to be actuated when said switch is actuated to apply power to an associated output conductor, said lights including color coded lenses corresponding to said color coded output conductors coupled thereto.

9. The apparatus as defined in claim 8 and further including a second series of switches, each having first and second terminals electrically coupled to one another when the switch is in a closed position wherein a first terminal of each of said second switches are coupled to said primary winding of said transformer, a second output jack adapted to receive a second plug having a plurality of second color coded conductors coupled thereto, said output jack having a plurality of terminals coupled to corresponding second terminals of said second series of switches, and a second series of indicator lights coupled to said second terminals of each of said second series of switches to be actuated when said corresponding switch is actuated to apply power to an associated output conductor, said second series of lights including color coded lenses corresponding to said second color coded conductors coupled thereto.

10. The apparatus as defined in claim 9 wherein said means coupling said terminals of said first switches to said at least one output jack includes a plurality of normally closed relay contacts, each contact being coupled in series between a switch and a corresponding terminal of said at least one output jack, and means for actuating said relay to open said contacts to disconnect said terminals of said output jack from said switches.

11. The apparatus as defined in claim 10 wherein said transformer, said first and second series of switches and lights, and said output jacks are positioned in a container having a storage area for output conductors and a hinged cover.