CA2307417A1 - Oil burner monitor and diagnostic apparatus - Google Patents

Abstract

An oil burner operation monitoring apparatus for enabling convenient diagnosis of problems with the flame in a burner. The apparatus is connected to the cad cell terminals located on the oil burner primary control. The device measures the voltage that is found across the cad cell terminals. By recording this voltage over period of time, and comparing this information with the status of other indicators in the oil burner such as the power to the motor and the thermostat, intermittent problems relating to flame problems are readily ascertained. The apparatus can be permanently mounted in the oil burner or temporarily connected. This apparatus eliminates the need for the technician to randomly replace parts such the cad cell or flame nozzle until the problem is located. The apparatus can also be used to a signal in the event of a fault that can be connected to various warning devices.

Description

Docket No. 1170-008 Express No. EM550711903US
OIL BURNER MONITOR AND DIAGNOSTIC APPARATUS
BACKGROUND OF THE INVENTION
1. Field of the Invention The invention relates to diagnostic tools for oil burners.

2. Description of the Related Art There is a need to log events that occur during the operation of an oil burner when 1o there is an intermittent problem that causes the oil burner primary control to cycle to a safety standby condition.
Occasionally, proper operation of an oil burner is interrupted by an intermittent condition that causes the burner to go to a condition, variously called safety standby, safety lockout, or to "go out on safety." When this occurs, manual resetting of the oil burner primary control by either,the resident or a service technician is required. This condition can be caused by a faulty part in the oil burner, a faulty oil burner primary control, fuel delivery problems, or an improper voltage condition on the line powering the ignition transformer.
When the service technician arrives, the intermittent condition causing the safety lockout may or may not be still present. The oil burner may operate satisfactorily for several days, only to go to safety lockout again, when the intermittent condition reoccurs.
This frustrating sequence can occur several times as presently the only method of diagnosis and repair available is to replace one part after another and wait to see if the problem reoccurs again. This can be several days or weeks later. Throughout this l .,, Docket No. 1170-008 Express No. EM550711903US
period, the resident of the property is unsure whether the heating system of the building is reliable and whether any absence coincidental to such an occurrence will result in significant damage to the building due to freezing conditions.
U.S. Patent No. 5,063,527, issued to Price et al. on November 5, 1991, discloses a monitoring system directed to controlling safety aspects of burners. This is done by referencing real time conditions relative to reference standards. The system does not disclose or suggest the need for monitoring an historical record of operation or the necessary structure to accomplish such monitoring.
U.S. Patent No. 5,005,142, issued to Lipchak et al. on April 2, 191, discloses a 1o sensor system for communicating to a control section which compares the signals to a standard and then sends a warning if there is significant deviation.
U.S. Patent No. 5,515,297, issued to the present inventor, on May 7, 1996, discloses an oil burner monitor and diagnostic apparatus. This device is connected to several key points in the oil burner. The device records and stores information concerning many of the key functions indicative of an oil burner's operation.
The device monitors whether the thermostat goes on and whether, within the next ten minutes, the ignition transformer voltage is turned on. If those events occur properly, then voltage at the primary leads of the ignition transformer and the vent stack temperature is monitored every five seconds for 50 seconds. While this device is substantial improvement over 2o existing methods and apparatus, it is unable to determine whether several types of flame problems that are especially difficult to diagnose.

Docket No. 1170-008 Express No. EM550711903US
U. S. Patent No. 5,612,904, also issued to the present inventor, on March 18, 1997, discloses an improvement in the invention disclosed in the '297 patent.
Here the inventor discloses the need for a permanently mounted unit for data collection that can be accessed through a portable data reading unit. However, the same events are monitored as taught in the '297. ' The typical oil burner uses a cadmium sulfide (cad) cell to indicate whether a flame is present. If after a pre-set period of time, no flame is detected, the oil burner is shut down. Shutting off power to the burner prevents a build up of unburned oil or the late ignition of a large amount of unburned oil.
1o The oil burner response is all or nothing. If too little flame is present, intermittent flame, or even if a small flame continues after the oil burner shuts off due to a slight dripping of oil, this situation would not be detected. This is especially a problem for a technician who is charged with repairing the unit. Typically, the technician will measure the resistance of the cad cell to try to determine whether it or the flame is functioning properly. However, this measurement is difficult to make. Furthermore, the measurement can only be done for a short period of time which could correspond to the time when the oil burner does not exhibit the problem. The resistance in ohms cannot be read when the circuit is actuated. Therefore, when servicing the burner, the technician will disconnect the cad cell wires and place a jumper across the terminals of the primary 2o controller. This permits the burner to maintain operation as it simulates a cad cell with the low resistance which is indicative of proper flame operation. Using an ohmmeter, the Docket No. 1170-008 Express No. EM550711903US
technician will then make resistance measurements of the cad cell. However, this procedure is clearly limited in time.
U.S. Patent No. 5,126,721, issued to Butcher et al. on June 30, 1992, discloses a flame quality monitor system that measures the quality of the flame utilizing a second cad cell, not the cad cell that is connected the primary control of the oil burner. Further, this device measures the resistance found in the second cad cell to determine whether excess air or sooting has progressed to the point where the oil burner should be serviced.
A system that logs the data history of a residential oil burner, accurately recording the history of events as those occurred concerning the history of the flame in the burner over a long period of time so that the record can viewed for diagnosis of the problem by measuring the voltage across the cad cell connected to the primary control of the oil burner is not taught in the prior art.
SUMMARY OF THE INVENTION
It is an aspect of the invention to provide an apparatus that monitors changes in the status of the flame in an oil burner system to permit a repair technician to monitor those events, recall past events, and diagnose intermittent problems that might not be duplicated when the repair technician is present.
It is another aspect of the invention to provide a hand-held device capable of monitoring changes in key oil burner functions.
zo It is still another aspect of the invention to provide a permanently mounted data collection unit that can be accessed through a portable data reading unit to diagnose Docket No. 1170-008 Express No. EM550711903US
the flame history in an oil burner.
It is still another aspect of the invention to provide an apparatus that is used to measure the flame history of the oil burner alone or can be used in combination with other sensing and monitoring equipment to monitor and diagnose all oil burner functions.
Another aspect of the invention is to provide an apparatus that can be used with a microprocessor to permit monitoring several channels of inputs of information from an oil burner system, process that information, store that information with date and time, and make that information accessible at a later time in an economical way.
It is still another aspect of the invention to provide immediate feedback of the 1o monitored events by displaying changes in their condition on the integral display screen as they occur in order to permit a repair technician to monitor those events in real-time.
It is still another aspect of the invention to provide an apparatus that monitors the cad cell to determine the status of the flame in the oil burner.
Another aspect of the invention is to provide an apparatus that will permit the 1 s determination of whether the flame is absent, weak or intermittently on and save that information so that it can be reviewed and diagnosed at a later time and/or location.
Still another aspect of the invention is to enable the technician to diagnose a lingering flame situation that prevents the primary controller from allowing the oil burner to restart.
2o Finally, it is an aspect of the invention to provide a device capable of determining when a fault condition has occurred in the proper operation of an oil burner by comparing Docket No. 1170-008 Express No. EM550711903US
the voltage across the terminals of the cad cell to a standard voltage that is present when the flame of the oil burner is operating properly.
The invention is a monitor that measures the voltage across the terminals of the cad cell to determine the presence, absence and quality of oil burner flame.
Before a flame is established, the voltage across the terminals is approximately 24 volts. After the flame is established, the voltage typically will be in the range of 5 to 6 volts, with the brighter the flame, the lower the voltage. The invention can be used as a stand alone monitor or as part of the inventor's oil burner monitoring apparatus as disclosed in U.S.
Patent Nos. 5,515,297 and 5,612,904, incorporated in their entirety by reference.
1o BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a block diagram of the invention.
Fig. 2 is a schematic of the preferred circuit for measuring the voltage across the cad cell in accordance with the invention.
DETAILED DESCRIPTION OF THE INVENTION
1 s The invention is a monitor and diagnostic apparatus that will record a sequence of relevant events relating to the flame history of the oil burner. The invention can be made as a stand-alone unit, either permanently attached to the oil burner or as a portable. The invention can also be made as part of the inventor's oil burner monitor and data logging apparatus as noted above.
2o By using this apparatus, the oil burner repair technician can review the logged events and determine the flame history of the oil burner. The invention enables the Docket No. 1170-008 Express No. EM550711903US
service technician to more quickly and efficiently repair a faulty system, especially systems that fail intermittently.
Referring now to Fig. 1, the invention is a device designed to monitor the flame history of the oil burner (not shown) by measuring the voltage that appears across terminals 16 and 18 that are connected to (cad) cell 12. As shown in Fig. 2, this can be accomplished using the circuit depicted or other such voltage measuring circuits well known in the art. Cad cell 12 controls the safety circuit (not shown) of the oil burner primary control 26. Once thermostat 20 calls for heat by sending a signal to oil burner primary control 26 via terminals 22 and 24, oil burner motor 36 is activated.
If, usually 1 o after 15 - 45 seconds, the cad cell 12 does not indicate that a proper flame 14 is present, then a safety circuit within primary control 26 will be activated in response to this condition, the power coming from lines 28 and 30 which supplies oil burner 36 via leads 32 and 34 will be disconnected and the oil burner will be shut down.
Cad cell 12 changes resistance corresponding to the amount of light that falls upon cad cell 12 due to flame 14. When flame 14 is absent, the resistance is high.
When the amount of light emitted by flame 14 is normal, the resistance of cad cell 12 is substantially lower. The "safety circuitry" in primary control 26 has a thermal element that heats in response to the additional current that flows through the "safety circuitry"
in response to the high resistance of cad cell 12. When there is sufficient heat in thermal element, the "safety circuitry" will trip and the burner will shut down, that is, a "safety lockout" will occur.
There are several oil burner problems that are simple to determine with the Docket No. 1170-008 Express No. EM550711903US
invention that cannot be found easily without it. The following situations are representative of oil burner problems that presently are very difficult to remedy.
A lingering flame 14 can occur when the oil burner is shut off. Since lingering flame 14 is substantially smaller than the proper sized flame 14, the oil burner motor is shut off, yet there is still a flame. This situation will not be detected using present methods. However, invention 10 will record via leads 32 and 34 that the oil burner motor is off and that cad cell voltage lies between 24 volts and 5 - 6 volts for a normal flame 14.
Invention 10, since it is recording these measurements over time, will indicate how long flame 14 lingered. As long as the flame 14 lingers, "safety circuitry" will not allow the 1o burner to start. Invention 10 will show a low voltage reading at the very beginning of a call for heat by thermostat 20, indicating that there is light falling on cad cell 12 from flame 14. This is a cause for intermittent burner failures which are extremely difficult to diagnose without invention 10.
If the oil burner has established flame 14 but flame 14 is poor quality, the voltage reading across cad cell 12 will be higher than normal. Depending on the flame 14 quality, the oil burner might even experience a "safety lockout". As above, this condition can also be intermittent. Invention 10 will show through measuring the voltage of cad cell 12 that the flame 14 is marginal even if flame 14 is sufficiently bright to keep cad cell 12 from tripping the "safety lockout".
2o If an oil burner has a history of intermittent failures, and if, during the operation of the oil burner, the voltage reading from cad cell 12 is within the acceptable voltage range, Docket No. 1170-008 Express No. EM550711903US
flame 14 can be ruled out as the cause of the problem.
If flame 14 goes out after flame 14 has been established, then the voltage across the terminals 16 and 18 will increase. This will show the technician that the cause for this intermittent failure was that flame 14 was extinguished which resulted in the oil burner being triggered into its "safety lockout" mode.
If invention 10 is made part of the complete oil burner monitor and diagnostic apparatus, either as a permanent part of the oil burner or a separate portable unit, as taught by the inventor in his '297 and '904 patents, monitoring and recording the voltage powering the ignition transformer, the temperature on the outside of the vent stack pipe, 1 o the thermostat, power to the oil burner motor and the voltage across the cad cell will enable a technician can easily determine any problem that oil burner is experiencing.
While there have been described what are at present considered to be the preferred embodiments of this invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention and it is, therefore, aimed to cover all such changes and modifications as fall within the true spirit and scope of the invention.

Claims (15)

1. A monitor and diagnostic apparatus for an oil burner having a primary control with a first pair of terminals connected to cad cell used to indicate the existence of a flame in the oil burner and with a second pair of terminals to provide power to the oil burner's motor, and with a third pair of terminals connected to a thermostat that sends a signal calling for heat, said apparatus comprising:
first sensor connected to the first pair of terminals for measuring the voltage occurring across said first pair of terminals;
second sensor connected to the second pair of terminals for measuring whether power is being supplied to the motor of the oil burner;
third sensor connected to the third pair of terminals for measuring whether a signal is being sent to the primary control of the oil burner;
central processor for processing the first, second, and third signals from said first, second and third sensors, respectively, said processor providing an output corresponding to the operational flame history of said oil burner over a pre-selected time interval.

2. The monitor and diagnostic apparatus of claim 1 further comprising:
a memory for recording the output of said central processor that corresponds to the flame history of said oil burner over a pre-selected time interval.

3. The monitor and diagnostic apparatus of claim 2 further comprising:
a display for displaying the recorded output of said memory such that a user of said apparatus can determine the operational flame history of said oil burner over a pre-selected time interval.

4. The monitor and diagnostic apparatus of claim 3 wherein said central processor processes said first signal and said second signal for a pre-selected fault time period, wherein said central processor provides a fault indicator signal indicating whenever a fault has occurred.

5. The monitor and diagnostic apparatus of claim 4 further comprising:
fault detector, once activated by the fault indicator signal provided by said central processor for ceasing operation of said memory and providing a fault alarm output signal that indicates a fault has occurred.

6. The monitor and diagnostic apparatus of claim 5 further comprising:
a keyboard for accessing the output stored in said memory that corresponds to the operation history of said oil burner over a pre-selected time interval and causing said stored output to be displayed via said display.

7. A monitor and diagnostic apparatus for an oil burner, with said oil burner having a thermostat, a cad cell and an ignition transformer, with each having a measurable voltage independent from each other, and with said oil burner further having a vent stack with an outside measurable temperature, said oil burner having an operational history comprising a sequence of on/off cycles and performance events within each on/off cycle, said apparatus comprising:
a data recording unit comprising:
first sensor that provides a first signal corresponding to the voltage at the thermostat of said oil burner;
second sensor that provides a second signal based on measuring the voltage at the ignition transformer of said oil burner;
third sensor that provides a third signal corresponding to the temperature on the outside of the vent stack;
fourth sensor that provides a fourth signal based on measuring the voltage at the cad cell of said burner;
a central processor that processes said first, second, third signals, and fourth signals from said first, second, third, and fourth sensor, respectively, said central processor providing an output of at least one signal corresponding to the performance events of said oil burner over a pre-selected time interval;
a memory for recording the output of said central processor over the pre-selected time interval in the sequential order and timing corresponding to the performance events and sequence having occurred in said oil burner;
wherein, said pre-selected time interval extends over a plurality of on/off cycles such that said recorded output from said central processor can be used to diagnose the operational history of said oil burner.

8. The monitor and diagnostic apparatus of claim 7 further comprising a portable data reading unit comprising:
a display that displays said recorded output of said memory such that an operator of said apparatus can visually determine the operational history of said oil burner over the pre-selected time interval.

9. The monitor and diagnostic apparatus of claim 8 wherein said portable data reading unit further comprises:
a key pad adapted to accessing said recorded output stored in said memory wherein the operator of said apparatus can review the sequence of performance events that has occurred over the pre-selected time interval.

10. The monitor and diagnostic apparatus of claim 9 wherein said central processor processes said first signal, said second signal, and said fourth signal to provide a fault indicator signal and a time of occurrence if any one of the performance events of said oil burner during the pre-selected time interval results in a fault condition within said oil burner.

11. The monitor and diagnostic apparatus of claim 10 further comprising:
fault detector which is activated by the fault indicator signal, such that when said fault detector is activated, said memory ceases operation and a fault alarm output signal is provided that indicates to a downstream microprocessor that a fault has occurred.

12. A monitor and diagnostic apparatus for an oil burner having a primary control with a first pair of terminals connected to a cad cell used to indicate the existence of a flame in the oil burner, said apparatus comprising:
a voltage sensor connected to the pair of terminals which measure the voltage occurring across said first pair of terminals such that a signal is provided that corresponds

13 to the condition of the flame in the oil burner.

13. The monitor and diagnostic apparatus of claim 12 wherein said voltage sensor is permanently connected to the oil burner.

14. The monitor and diagnostic apparatus of claim 12 wherein the oil burner receives a call for heat, said voltage sensor provides a signal that is recorded.

15. The monitor and diagnostic apparatus of claim 14 wherein the signal that is recorded using a portable reader that is temporarily connected to said voltage sensor.