SERVICE PROCEDURE RG-V
Combination Thermostat/Gas Valve Testing
and Replacement
Combination Thermostat/Gas Valve Testing and Replacement
The combination thermostat/gas valve is a non repairable device. If trouble shooting has determined a problem with the combination thermostat/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 OK, the combination thermostat/gas valve may be faulty.
LINE PRESSURE
The combination thermostat/gas valve is designed for a maximum line pressure of 14.0" w.c. and a minimum line pressure of 1.0"w.c. over the water heater 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 combination thermostat/gas valve to “OFF” position.
Step 2. | Remove pressure tap plug (3/16" Allen wrench) and install |
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| pressure tap (7/16 wrench) |
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Step 3. | Connect manometer to pressure tap. |
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Step 4 | Follow lighting instructions and proceed to light | Pressure Tap |
| main burner and observe manometer reading. | Shown Installed |
Step 5 | Proper operating range for natural gas is 4.0 ±0.3" W.C. |
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| Proper operating range for L.P. gas is 10.0 ±0.5" W.C. |
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Step 6 | If pressure is OK, set combination thermostat/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. If pressure is out of the specification noted in step 5, proceed to step 7 or 8 for proper | |
| service procedure. |
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Step 7 | For White Rodgers control, the manifold pressure is not adjustable. If manifold pressure is outside the range | |
| in step 5, the control must be replaced. |
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Step 8 | For Robertshaw control, the manifold pressure is adjustable, proceed to step 9 for adjustment procedure | |
Step 9 | While burner is in operation, remove regulator access cap to expose the regulator adjusting screw. With small | |
| screw driver, rotate adjusting screw clockwise to increase pressure and counter clockwise to decrease pressure. | |
Step 10 Replace regulator access cap, set combination thermostat/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.
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