Draft inducer system
Dual firing rate flame sensing system
Dual fuel vent free gas heater
Dual rate burner construction and method of making the same
Dual-valve air-gas controller
Dynamically checked safety load switching circuit
Electric ignition system
Electrical controls for heating appliances
Electrical ignition systems for gas fired equipment
Electrically enhanced hot surface igniter
Electronic carburetion system for low exhaust emissions of inter
Electronic control arrangement for detecting a leak condition fo
Electronic controller for fluid fuel burner
Electronic fuel convertibility selection
Electronic safety device for a fluid, particularly gaseous, fuel
Electronic valve seat leak detector
Energy saving boiler purge sequence control
Excess gas burner
Exhaust stack damper control
Fail safe automatic flue damper mechanism