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US 4,789,329 AGranted
Thermostatically operated fuel valve control circuit
AssigneeHoneywell Inc.
InventorsJohn E. Bohan, Jr., John L. Erdman, Marvin D. Nelson, James W. Ratz
Life of this patent
Estimating the term…
Abstract
A control circuit for a fuel valve in a gas fired furnace controlled by an electronic thermostat is disclosed. The thermostat requires a load current to properly operate, and a pickup and hold circuit along with a time delay circuit are integrated to control a load current circuit to provide the correct load current for the thermostat.
Claims7
A control circuit for fuel valve means adapted for use with a heating system having a spark ignition device, a flame responsive switch, and a thermostat requiring an electrical load current, including:
- fuel valve means having pilot valve operating means and main fuel operating means;
- pickup and hold circuit means for said pilot valve operating means including connection means connected to a source of power through said thermostat upon a call for system operation and said flame responsive switch when said switch is in a cold position to thereby energize said pilot valve operating means;
- load current circuit means including connection means connected to draw a first level of said load current through said thermostat upon said call for operation of said system;
- time delay circuit means including connection means connected to said source of power through said thermostat upon said call for system operation and said flame responsive switch when said flame responsive switch is in a hot position to energize said time delay circuit means;
- said time delay circuit means including said main valve operating means;
- and said time delay circuit connection means connected to said load current circuit means and causing said load current circuit means to maintain said load current upon said time delay circuit means timing out a time delay interval.
3 more elements
Dependencies are inferred from the claim text.