Voltage Test - Girard Products GSWH-2 Technical Manual

Mixing of hot and cold water will restrict the water flow through the water heater. When mixing hot and cold water at the
faucet you will start to diminish the flow through the water heater. When the flow is low enough the board will no longer
sense that there is enough flow of water and the board will turn off the operation of the water heater.
Other plumbing issues can cause a mixing of hot and cold water. Winterization bypass kits may be set incorrectly causing a
mixing hot and cold water. Also, in many cases, if you turn on the outside shower valves and turn off the shower head you
will mix hot and cold water through the system.
Another plumbing issue is the polarity of the water flow through the water heater. If the plumbing lines are reversed then the
impeller in the flow sensor will not activate. The fins in the flow meter spin the water which spins the impellers. If water is
going the wrong way through the water heater the impellers will not spin and the flow meter will not operate.
We have seen grease like deposits on the impellers of the flow meter causing the flow meter to read slower the actual water
flow is through the water heater. If the water heater will not turn on above .80 GPM and plumbing issues are eliminated then
the flow meter will need to be changed.

Voltage test

This test will confirm if the impellor is turning but will not tell you the actual water flow. If you do not see a voltage drop to
approximately two volts then 1) the impellor is jammed 2) the water is not flowing through the water heater 3) the water is
flowing the wrong way through the water heater 4) the Reed switch of the flow meter has malfunctioned.
Water flow Sensor
wire connector
Water flow off:
5 VDC between the black and the red.
5 VDC between the black and the Yellow.
Water Flow On:
5 VDC between the black and the red.
2.6 VDC between the black and the yellow.
Note that if the flow meter fails it will not generate a fault code. The water
heater will simply not turn on.
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