GAS VALVE TESTING AND REPLACEMENT (White Rodgers Mechanical)
The gas valve 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 function, 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.
The gas valve is designed for a maximum line pressure of 14.0″ W.C., and a minimum line pressure based on the manifold pressure plus 1.0″ W.C. (check rating plate for rated manifold pressure). Line pressure must be checked with burner on and burner off to assure proper readings.
MANIFOLD PRESSURE TESTING
(This procedure assumes a maximum line pressure of 14.0″ W.C.)
Step 1. Set gas valve to “OFF” position.
Step 2. Remove the pressure tap plug (3/16” Allen wrench) and install pressure tap.
Step 3. Connect the manometer to pressure tap.
Step 4. Follow the lighting instructions and proceed to light main burner and observe manometer reading.
Step 5. Proper operating range for natural gas is 4.0 ±0.5″ W.C.
Proper operating range for L.P. gas is 10.0 ±0.5″ W.C.
a. If pressure is O.K., set gas valve to “OFF” remove manometer and pressure tap and replace pressure tap plug. Check for gas leaks before placing water heater back in operation.
b. If pressure is out of the specification noted above, proceed to Step 6 for proper service procedure.
Step 6. The manifold pressure is NOT adjustable. If manifold pressure is outside of the range in Step 5, the control must be replaced.