ADC ML-190, ML-175 service manual

To Replace Gas Valve

(Refer to burner illustration on the next page)

Discontinue electrical power to the dryer.

Close shutoff valve(s) in gas supply line.

Disconnect gas valve wiring.

NOTE: Identify location of each wire for correct reinstallation.

Break union connection before gas valve.

Loosen and remove screws (4) securing pipe brackets to burner.

Remove gas valve/manifold assembly from dryer.

Remove valve mounting bracket, manifold, and piping from gas valve.

Reverse procedure for installing new gas valve.

▲! WARNING

Test all connections for leaks by brushing on a soapy water solution.

Never test for leaks with a flame!!!

To Replace Main Burner Orifices

Refer to “To Replace Gas Valve” and follow the steps until manifold is removed then 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.

Reversing the removal procedure for reinstalling.

▲! WARNING

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) Pressure

There are two 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.

To Test Gas Water Column Pressure:

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.

Start dryer. With burner on, the correct water column reading in inches would be:

Natural Gas – 3.5 in wc; L.P. Gas – 10.5 in wc

To Adjust Water Column Pressure (natural gas only, L.P. gas must be regulated at source):

Remove the slotted vent cap on the top of the valve.

Turn the slotted adjustment screw, located on the top of the valve next to the terminals clockwise to increase manifold pressure and counterclockwise 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.

12 American Dryer Corporation 450431 - 3