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To Test and Adjust Gas (Water Column) Pressure
There are two (2) types of devices commonly used to measure water column pressure. They are spring/mechanical-
type gauges and manometers. The spring/mechanical-type gauge is not recommended, because it is easily
damaged and not always accurate. A manometer is simply a glass or transparent plastic tube with a scale in
inches. When filled with water and pressure applied, the water in the tube rises showing the exact water column
pressure.
NOTE: Manometers are available from the factory by ordering ADC P/N 122804
1. To Test Gas Water Column (W.C.) Pressure:
a. Connect water column test gauge connection
to gas valve pressure tap (1/8" NPT). This
pressure tap is located on the outlet (manifold)
side of the valve.
b. Start dryer. With burner on, the correct water
column reading in inches would be:
Natural Gas 3.5 to 4 Inches Water Column
L.P. Gas 10.5 to 11 Inches Water Column
2. To Adjust Water Column Pressure (natural gas only,
L.P. gas must be regulated at source):
a. Remove the slotted vent cap on the top of the valve.
b. Turn the slotted adjustment screw located on the top
of the valve next to the terminals. Turn clockwise to
increase manifold pressure and counterclockwise to
decrease.
NOTE: If correct W.C. pressure cannot be achieved, problem may be due to an undersized gas
supply line, a faulty or underrated gas meter, etc.