20
2. Unscrew main burner orifices and replace.
NOTE:
Use extreme care when removing and replacing orifices. These orifices are made of brass and
are easily damaged.
3. Reversing the removal procedure for reinstalling.
NOTE:
Test
ALL
connections for leaks by brushing on a soapy water solution. NEVER TEST FOR
LEAKS WITH A FLAME.
To Test and Adjust Gas (Water Column [W.C.]) 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 pressure:
a. Connect water column test gauge connection
to gas valve pressure tap (1/8” N.P.T.). 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 inches (8.7 mb) water
column.
Liquid Propane (L.P.) Gas – 10.5 inches (26.1
mb) 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 (CW) to increase manifold pressure
and counterclockwise (CCW) to decrease.
NOTE:
If correct water column pressure
cannot
be achieved, problem may be due to an undersized
gas supply line, a faulty or underrated gas meter, etc.
Summary of Contents for AD-758
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