Girard Products GSWH-2 Technical Manual page 18

Gas Valve
Output Test Port
Linear Valve Side
The board also sends voltage to the linear (modulator) side of the gas valve on the red (+) and white (-) wires at the 8 wire
connector at the bottom of the board. The Voltage will vary from 11.24VDC in low and 18VDC and upward to 20VDC. As
voltage increases the plunger in the valve is pushed downward allowing for more gas flow to the burner.
Even though we are able to test the voltage with a volt meter the actual voltage the control board is sending to gas valves is
not standard DC volts. The actual voltage shown below is more energy efficient and this is also how the control board
measures the operation of the linear valve.
5. Check voltage between the brown and the black wires during the
trial for ignition. You should have 12VDC
6. The resistance on the coil should be approximately 110 ohms.
7. The output gas pressure of the gas valve can be measured at the test
port on the right side of the board. There should be 1.5" WC on low
heat and 7.8" WC on high heat. If there is no pressure, then the gas
valve is not opening.
8. Restrictions in the gas system can prevent gas from getting to the
water heater. Just because there is gas everywhere else doesn't
mean you actually have good gas flow to the water heater.
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