Actuator for rotary damper of gas fired water heater flue with rotary piston connected to diaphragm and operating over lost motion distance to open outlet so that a connected damper is opened before gas can flow through for firing heater

摘要

A system to reduce standby losses in a hot water heater is presented. The system utilizes a dual safety relay valve between the combination gas controller and the burner. The dual safety relay valve bypasses gas to a rotary damper actuator valve to position a damper flapper valve located over/inside the flue pipe. Once the flapper valve has opened to ensure combustion, the gas is allowed to flow back to the dual safety relay valve. Some of the bypass gas may be diverted to boost the pilot or to supply a booster. The dual safety relay valve is then opened to allow the gas supply to the burner. Once the burner is turned off, bypass gas bleeds out of the rotary damper actuator valve to close the damper flapper valve to reduce standby losses through the flue pipe, and to allow the dual safety relay valve to close tightly. In a particular embodiment a diaphragm is moved by gas pressure to drag a safety valve connection hook a predetermined distance before the safety valve is caused to open when the flap damper would have been sufficiently opened.