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3.5.13 Regulator Valve
In a gas dryer, the regulator valve forms part of the gas control system and performs the
function of regulating the gas pressure into the burner venturi and turning the gas flow on
and off.
The regulator valve consists of two solenoid shut-off valves, a gas pressure regulator and
a gas orifice assembled into a single cast body. The pressure regulator is factory set to
maintain 3½ inches of water column (WC) gas pressure at the orifice (0.87kPa). The
regulator is service adjustable. The two solenoid valves are in series such that the gas
flowing through the pressure regulator must pass through both valves to get to the orifice
and burner. At dryer start up, the gas igniter is energised and the first valve is opened.
Once the gas igniter has reached ignition temperature, the gas flame detector operates the
second valve, allowing gas to flow through the orifice and into the burner venturi, and
ignition takes place. The second valve is held open only when a flame or hot ignition is
detected by the gas flame detector.
The orifice is a precisely drilled brass plug screwed into the outlet port of the regulator
valve. The orifice extends into the burner venturi. The combination of regulated pressure
and orifice size provides the proper volume of gas for the heat rating of the burner. The
regulator valve comes from the factory sized and adjusted to deliver heat at the rate of
20,000 BTUs per hour, using natural gas.
While natural gas is most commonly used, the regulator valve is also able to
accommodate the use of LPG. In this case, a LPG conversion kit (part number 395489) is
used to modify the regulator valve to achieve the correct volume of gas flow for LPG.
Gas Pipe
Gas Flow
Regulator
and Valves
Orifice
Igniter
Flame Detector
Information fed back
to gas flow regulator
and valves from
Combustion
Chamber
Gas Pipe
Gas Flow
Regulator and
Valves
Burner
Venturi
Orifice
Igniter
Igniter
Bracket
Gas Burner Assembly
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