American Dryer Corp. AD-670 - Manual (Page 37)

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B. MAIN GAS SUPPLY LINE
The main gas supply line is a 2” N.P.T. line, which feeds the gas required for both high and lo-fire.
1. Main Gas Valve - The main gas valve is a double solenoid gas valve containing two (2) safety shutoff
valves in one (1) housing. It is a fast opening, fast close valve and is used to feed both high and lo-fire gas
lines. This valve has been pre-adjusted at the factory for both natural and liquid propane (L.P.) gases.
2. High Fire Gas Valve - The high fire gas valve is a 2-inch (5.08 cm) adjustable electrohydraulic gas shutoff
valve. It is slow opening and fast closing with adjustability for flow rate. Although this valve has been
preset at the factory this valve may need to be readjusted at time of installation.
a. High Fire Gas Valve Adjustment:
1) Loosen the pan head screw until you can manually rotate the flow adjustment cap for 1-1/2 to 2
turns.
2) While holding the valve body turn the flow adjustment cap clockwise (CW) for less gas or
counterclockwise (CCW) for more gas. Referring to the “Vmax Diagram” on the top of the flow
adjustment cap base.
3) Check the flame at the gas burner with an orifice or flow meter until you have achieved the desired
flow.
4) Tighten the pan head screw on the flow adjustment cap.