ADC ML-190, ML-175 service manual

Page 12

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.

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American Dryer Corporation

450431 - 3

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Contents ML-175 / ML-190 American Dryer CorporationRetain This Manual in a Safe Place for Future Reference Date of Purchase Model no RESELLER’S Name Serial NumbersTable of Contents Routine Maintenance Safety PrecautionsCleaning Important InformationInstallation Requirements Operational Service Check Procedure Description of PartsCompressed Air Requirements Electrical and Gas RequirementsGas Burner Assembly Reversing Relay PanelSteam Coil and Damper System Steam Coil pH LevelIdler Shaft Assembly Rotational Sensor AssemblySpeed Reducing Shaft Drive ShaftMain Door Switch Sail Switch Gas Models OnlyBurner Hi-Limit Gas Models Only Tumbler Hi-LimitLint Drawer Switch Computer Controls Lint DrawerIntroduction Ignition Controls Page Thermostats To Convert from Natural Gas to L.P. GasTo Replace Burner Hi-Limit Thermostat Gas Models Only Sail Switch Assembly Gas Models Only Front Panel and Main Door AssembliesTo Install New Main Door Glass PulleysTo Replace Front Panel To Replace Drive Shaft PulleysTumbler Alignment BearingsTo Replace Motor Pulley To Replace Drive/Idler Shaft Pillow Block BearingsRotational Sensor Switch Replacement To Replace Speed Reducing Shaft BearingsTo Replace Rear Tumbler Shaft Support Wheels Basket and Support BeltsMotors Lint Drawer Assembly ImpellorTo Replace Fan Shaft and/or Fan Shaft Bearings To Replace Lint ScreenTroubleshooting Phase 6 OPL System Diagnostics Diagnostic L.E.D. Display Failure CodesBurner hi-limit safety thermostat is tripping Overload for impellor fan motor is trippingD. Display Indicators D. Display Indicator NumberFAN Blower Output L.E.D. Indicator AIR AIR JET Output L.E.D. Indicator OptionalHT1 Heat Output L.E.D. Indicator Fuse Main Fuse Input L.E.D. IndicatorPhase 7 OPL System Diagnostics Input / Output Board L.E.D. Indicators Technical InformationMotor Plate High and Low Voltage ExampleUsing a Manometer How To Use a ManometerData Label Tool List450431 ADC Part No 3 06/17/08
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