A regulating device may include a housing that defines an inlet chamber and an outlet chamber, with a flow restriction seat between the inlet chamber and the outlet chamber. A flow restriction valve is movable relative to the flow restriction seat to adjust the flow between the inlet chamber and the outlet chamber of the regulating device. A servo valve having a servo chamber may be used to adjust the position of the flow restriction valve. The servo chamber may be fluidly coupled to the inlet chamber though a fixed flow restriction and to the outlet chamber though an adjustable flow restriction. A stepper motor may be used to adjust the servo valve to adjust the adjustable flow restriction between the servo chamber and the outlet chamber. This causes a change of the servo pressure, which moves the flow restriction valve and adjusts the flow of the regulating device.

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.

A gas flow controller for use in a gas-fired apparatus including a pilot burner and a main burner is provided. The controller includes a housing defining a diaphragm chamber, a pilot valve operable to open and close a first fluid flow path between a gas supply inlet of the gas flow controller and the diaphragm chamber, and a main burner valve operable to open and close a second fluid flow path between the gas supply inlet and the main burner. The main burner valve includes a diaphragm that is disposed within the diaphragm chamber and includes a central portion and an annular outer portion. The outer portion is configured to deflect into engagement with the housing to close a third fluid flow path in response to an over-pressure condition at the gas supply inlet.

A gas flow controller for use in a gas fired apparatus includes an actuator, a pilot valve operably connected to the actuator, a main burner valve, and a flow controller valve operably connected to the actuator. The pilot valve is moveable from a closed position to an open position by actuation of the actuator to provide selective fluid communication between a gas inlet and a first fluid chamber. The main burner valve provides selective fluid communication between the first fluid chamber and a main burner outlet. The flow controller valve is moveable from a closed position to an open position by actuation of the actuator to provide selective fluid communication between the gas inlet and a back side of the main burner valve to maintain the main burner valve in a closed position when the pilot valve is in the open position.

A controller is provided for a gas valve including a movable valve element, a main diaphragm chamber having a main diaphragm therein coupled to the valve element to displace the valve element relative to a valve opening, and a servo-regulator diaphragm for regulating flow of gas that acts against the main diaphragm, to adjust the valve element and vary the flow rate. A stepper motor is configured to move in a stepwise manner to displace the servo-regulator diaphragm to adjust the valve element and gas flow rate. The controller for the stepper motor includes a microprocessor that receives an input signal indicating an operating capacity level, and determines the steps the stepper motor must move to displace the servo-regulator diaphragm to establish a flow rate corresponding to the operating capacity level. The microprocessor generates a signal to move the stepper motor the number of steps to adjust the gas valve.

Fluid control apparatus having flow restrictors are described herein. An example actuator includes an actuator housing having an actuator to define a first chamber of the actuator housing and a second chamber of the actuator housing. A loading fluid pathway is formed in the actuator housing to fluidly couple a loading fluid and the first chamber. A restrictor is positioned within the loading fluid pathway to regulate a flow rate of the loading fluid that is to flow from an inlet port of the loading fluid pathway to the first chamber.