DV Series
20
Gas Valve Testing and Replacement (White Rodgers Mechanical)
The gas valve on the White Rodgers Mechanical is a non-repairable device. If troubleshooting has
determined a problem with the gas valve, it must be replaced.
If the burner and/or pilot do not fuction, service checks for gas pressure, thermocouple output,
magnet assembly, and ECO are to be performed. If these check O.K., the gas valve may be faulty.
Magnet Assembly Testing (White Rodgers Mechanical)
Step 1. Following the lighting instruction label on the heater, proceed to light the pilot and allow to
operate for three minutes. If the pilot will not stay lit, hold the pilot button (located on gas
valve) down during this test.
Step 2. Using a multimeter capable of measuring millivolts, connect one lead using an alligator clip
to the copper sheath of the thermocouple. Use the second lead of the multimeter to probe
the top terminal located at the back of the gas valve.
Step 3. With a meter reading of 13 millivolts or greater, rotate the knob of the combination
thermostat/gas valve to the “OFF” position.
Step 4. The magnet should remain
closed for a drop of at least 6 millivolts. You will hear a “snap”
or “click” sound when the magnet opens; if you hear this sound prior to a drop of 6
millivolts, the magnet is out of specification and the gas valve should be replaced.
Energy Cut Off (ECO) Testing
Step 1. Disconnect the thermocouple from the gas valve.
Step 2. Using a multimeter capable of measuring ohms (or
continuity), attach one lead using an alligator clip to the
pilot tube. Insert the other lead fully into the magnet
opening. Be sure the lead makes contact only at the top
center of the magnet opening. DO NOT allow the lead to
make contact with the threaded sides of the opening.
Step 3. If continuity is indicated, the ECO is O.K.. If continuity is not
indicated, the ECO has opened, and the gas valve must be replaced.
Alligator clip to copper
sheath of thermocouple
Service Procedure IV
Gas Control Testing and
Replacement
20
