Gas fired burner control system - has timer controlled solenoid valve with by=pass opened when thermostatic valve is closed

摘要

Solenoid actuated normally closed valve (20) supplies gas to a burner (10) with a flame sensor (25) controlled valve (24). The valve (20) is by passed by a valve (23) which can be closed manually. Valve (23) is however connected to a valve (18) controlled by a thermostat or manually such that when valve (18) is closed the by pass valve is opened. The by pass valve is arranged to allow gas to reach burner (10) even during a power failure when the solenoid operated valve (20) is inoperable. The arrangement is said to avoid the problem of preventing automatic operation is following a manual bypass operation the bypass is not reset.