Pool Heater Question

Old 08-08-11, 06:21 PM
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Pool Heater Question

Pool Heater is a millivolt system. Thermopile generates approx 450mv. Pool heater works fine but if I turn off the pool heater at the rocker switch, and turn it back on it can sometimes take up to 5 minutes to come back on. Sometimes it comes on right away. Is my thermopile not generating enough mv or is a switch creating too much resistance?
Old 08-08-11, 06:56 PM
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450 mv is definitely on the low side, it should be about 750 mv. It could also be a matter of too much resistance somewhere in the circuit. I suggest cleaning all the wiring contacts and also cleaning the pilot assembly and making sure the powerpile is fully engulfed by the pilot flame.
Old 08-08-11, 07:01 PM
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I may be mistaken but as I recall, most pool heaters use a 750mV powerpile. If you can get the make & model of the gas valve, I can likely find out its power requirements.
Old 08-08-11, 08:33 PM
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Depends on how you took the millivolt read. Was 450 a closed read? You must also take a read across other components to decide if there is resistance. A 450 mv read indicates you do have a 750mv generator. My experience has been: dirty pilot, restricted pilot orifice or poor connection somewhere. Seldom is the generator the culprit. You may also want to check the filter and make sure it is clean. It may be dirty and not allowing proper water flow and the pressure switch is not closing.

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