water hater won't light

Old 12-20-10, 04:36 AM
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water hater won't light

I have a 6 year old AO Smith propane water heater, model #GPSH 50-101. The heater wont light by itself and the error code says the system is in lockout. 1. gas supply is off or too low to operate. 2. hot surface ignitor is not positioned correctly. 3. low voltage to the water heater. 4. electric polarity to the unit is incorrect. my propane tank is full. If I unplug the unit from the wall and plug it back in it tries to light 3 times and shuts itself off and shows the same error code. If I unplug the 3 wires that go to hot surface ignitor and sensor and plug them back in,it will light and work great. Do I need to replace these parts or could it be something else?
Old 12-20-10, 08:08 AM
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I think we responded to this question before. I would say check what its telling you.

1) Check the gas pressure. Propane gas valves are 10" water coloumn(I think) and not 3.5 inch like regular gas. Also check the pressure before the gas valve. While is running? This is a test procedure to determain gas issues.
2)If the igniter was not positioned then it would not light after you do what you do to get it to light.
3)Check the voltage.
4) check the polarity

What has changed? Have you done electrical work?

From working on these in the past I would say HSI or gas valve. Like I said call AO Smith. You may get the parts for free. I am leaning more towards gas valve issue. There is a small resistor on the HSI though and these fail. Its a black rubber coated looking jumper on the molex connector you have been unpluging.

Mike NJ

Mike NJ

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