Patent US3968665A successfully refreshed from Google Patents.
Patent US5076780A successfully refreshed from Google Patents.
US5076780A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Digital controller component failure detection for gas appliance ignition function
Assignee: Honeywell Inc
•
Filing: 1990-10-10
•
Granted: 1991-12-31
•
Expires: 2010-10-10
Abstract
Abstract A digital control system, for a gas-fired, forced combustion air heating appliance, controls operation of a combustion air blower and a gas valve as a function of essentially square wave input signals derived from a thermostat, a combustion air proving sensor switch, and a gas valve control relay. When a first input signal from the thermostat demands heat, the control system first checks for the presence of a second input signal (which indicates the status of the combustion air sensor switch) before starting the combustion air blower. If the second input signal indicates that combustion air is being delivered before the combustion air blower has started, the control system immediately halts the ignition sequence. If the combustion air sensor switch is functioning properly, the ignition sequence continues and the control system checks a third input signal to determine the status of the contacts of the gas valve relay. If the third input signal indicates that the relay contacts which power the gas valve are already closed before the gas valve relay coil is energized, the control system halts the ignition sequence by turning off the combustion air blower, causing the combustion air sensor switch to open and shut off power to the gas valve.
Inventors
- 👤 John L. Erdman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 10:41
CPC Classifications
F; F23; F23N; F23N5/00; F23N5/24; F23N5/242; F23N5/20; F23N5/203; F23N2223/00; F23N2223/08; F23N2225/00; F23N2225/04; F23N2225/06; F23N2231/00; F23N2231/10; F23N2233/00; F23N2233/06; F23N2235/00; F23N2235/12; F23N2235/14; F23N5/02; F23N5/12; F23N5/18
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
141 words
A control system for a gas-fired heating appliance comprising: a plurality of sensors, including a combustion air pressure switch, in a serial energization path for providing sinusoidal alternating current sensor signals indicative of conditions related to an ignition sequence of the appliance; signal conditioning means connected to the plurality of sensors for converting the sensor signals to a plurality of periodically alternating input signals; controller means for controlling the appliance to initiate the ignition sequence as a function of the presence or absence of the periodically alternating input signals; a gas valve connected in the serial energization path; and a gas valve relay having a gas valve relay coil connected between the serial energization path and the controller means and having gas valve relay contacts connected in the serial energization path between the gas valve relay coil and the gas valve.
Claim 2
Dependent Claim
141 words
A control system for a gas-fired heating appliance comprising: a plurality of sensors, including a combustion air pressure switch, in a serial energization path for providing sinusoidal alternating current sensor signals indicative of conditions related to an ignition sequence of the appliance; signal conditioning means connected to the plurality of sensors for converting the sensor signals to a plurality of periodically alternating input signals; controller means for controlling the appliance to initiate the ignition sequence as a function of the presence or absence of the periodically alternating input signals; a gas valve connected in the serial energization path; and a gas valve relay having a gas valve relay coil connected between the serial energization path and the controller means and having gas valve relay contacts connected in the serial energization path between the gas valve relay coil and the gas valve.
Claim 3
Dependent Claim
34 words
The control system of claim 1 wherein the plurality of sensors includes a thermostat, and wherein presence of one of the plurality of input signals indicates that the thermostat is making a heat demand.
Claim 4
Dependent Claim
23 words
The control system of claim 1 wherein presence of one of the input signals indicates that the combustion air pressure switch is closed.
Claim 5
Dependent Claim
21 words
The control system of claim 1 wherein the controller means controls operation of the gas valve through the gas valve relay.
Claim 6
Dependent Claim
27 words
The control system of claim 4 wherein the plurality of sensors includes means for providing a sensor signal indicative of a state of the gas valve relay.
Claim 7
Dependent Claim
37 words
The control system of claim 5 wherein the gas valve relay contacts are normally open and wherein the sensor signal indicative of a state of the gas valve relay indicates whether the normally open contacts are closed.
Claim 8
Dependent Claim
37 words
The control system of claim 1 wherein the plurality of sensors include a high limit thermal switch, and wherein presence of one of the plurality of input signals indicates that the high limit thermal switch is closed.
Claim 9
Dependent Claim
59 words
The control system of claim 1 wherein the appliance includes a gas ignitor and a flame sensor; wherein the control system further includes means for providing a flame sensor signal to the controller means which is indicative of presence of a flame; and wherein the controller means controls operation of the gas igniter as part of the ignition sequence.
Claim 10
Dependent Claim
14 words
The control system of claim 1 wherein the controller means includes a digital computer.
Claim 11
Dependent Claim
27 words
The control system of claim 9 wherein the signal conditioning means converts the sensor signals to input signals which periodically alternate between first and second logic levels.
Claim 12
Dependent Claim
80 words
The control system of claim 1 wherein: the appliance includes a combustion air blower; the plurality of sensors include a thermostat; the controller means controls the combustion air blower through a blower control relay; and the blower control relay includes a first pair of relay contacts connected to the combustion air blower for controlling energization of the combustion air blower and a second pair of relay contacts connected in the serial energization path for controlling energization of the gas valve.
Claim 13
Dependent Claim
46 words
The control system of claim 11 wherein the signal conditioning means provides a first input signal which indicates by its presence that the thermostat is demanding heat, and provides a second input signal which indicates by its presence that the combustion air pressure switch is closed.
Claim 14
Dependent Claim
38 words
The control system of claim 12 wherein the signal conditioning means provides a third input signal which indicates by its presence that the gas valve control relay is in a state in which the gas valve is closed.
Claim 15
Dependent Claim
46 words
The control system of claim 13 wherein the controller means terminates the ignition sequence unless presence of the first, second and third input signals has a predetermined temporal relationship to energization by the controller means of the gas valve control relay and the blower control relay.
Claim 16
Dependent Claim
152 words
A control system for a gas-fired heating appliance comprising: a plurality of sensors, including a combustion air pressure switch, in a serial energization path for providing sensor signals indicative of conditions related to an ignition sequence of the appliance; signal conditioning means connected to the plurality of sensors for converting the sensor signals to a plurality of periodically alternating input signals; controller means for controlling the appliance to initiate the ignition sequence as a function of the periodically alternating input signals; a combustion air blower controlled by the controller means; wherein the controller means includes a gas valve control relay with a pair of normally open relay contacts in the serial energization path; and wherein the controller means further includes a combustion air blower relay with a set of normally open relay contacts in the serial energization path and connected between the combustion air pressure switch and the gas valve control relay.
Claim 17
Dependent Claim
152 words
A control system for a gas-fired heating appliance comprising: a plurality of sensors, including a combustion air pressure switch, in a serial energization path for providing sensor signals indicative of conditions related to an ignition sequence of the appliance; signal conditioning means connected to the plurality of sensors for converting the sensor signals to a plurality of periodically alternating input signals; controller means for controlling the appliance to initiate the ignition sequence as a function of the periodically alternating input signals; a combustion air blower controlled by the controller means; wherein the controller means includes a gas valve control relay with a pair of normally open relay contacts in the serial energization path; and wherein the controller means further includes a combustion air blower relay with a set of normally open relay contacts in the serial energization path and connected between the combustion air pressure switch and the gas valve control relay.
References Cited (Backward Citations)
US4189296A
Cited
US4348169A
Cited
US4239477A
Cited
US4278419A
Cited
US4295129A
Cited
US4298334A
Cited
US4384844A
Cited
US4421268A
Cited
US4374569A
Cited
US4527125A
Cited
US4545009A
Cited
US4439139A
Cited
US4518345A
Cited
US4885573A
Cited
US4842510A
Cited
US4850852A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-12-30 | 1995-07-01 | 1995-12-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-12-30 | 1999-07-01 | 1999-12-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-12-30 | 2003-07-01 | 2003-12-31 | $7700.00 | Window Closed / Lapsed |