Pentair MasterTemp heats spa and then gives Service Heater light

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stevebrain

stevebrain

0
Dec 10, 2017
6
Folsom
I’m having a strange issue with my pool heater. It comes on fine and heats the spa up to what I set it to, usually 100 degrees. But after it reaches that temp and turns the gas off, it never comes back on again, so the temperature drops in the spa. Instead of cycling on again, the Service Heater light comes on. Even if I shut the heater and filter off for up to ½ hour, it will just go back to the Service Heater light coming on. The next day I can head it up to 100 again, but then it does the same thing after it reaches 100. There are no lights on the back of the control board coming on and no codes on the front display. But the LED on the ignition module flashes 2 times continually, which indicates “flame no call for heat”. Any ideas what might be happening here?



In ground 16,000 gal, plaster, spa, cartridge filter, 2 speed pump, Mastertemp 400 heater, Polaris 360, about 20 years old
 
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Welcome to the forum.

Can you provide more information on your entire equipment set up? Best way to do this is by adding a signature. See Pool School - Getting Started

Once you provide that additional information others will join in to provide some guidance.

Take care.
 
These are always hard to diagnose. Sounds like you have a basic system meaning no automation to control it. For me, I would first suspect maybe the control module. The module thinks that the flame is still burning. Since you say you shut it off for half hour, I would suspect that there is no flame on the unit.
 
ps0303 said:
These are always hard to diagnose. Sounds like you have a basic system meaning no automation to control it. For me, I would first suspect maybe the control module. The module thinks that the flame is still burning. Since you say you shut it off for half hour, I would suspect that there is no flame on the unit.
Click to expand...

Yes, the flame is out for sure. After some research I read that the igniter is supposed to act as a flame sensor after ignition (is that true??), to I thought maybe it's continuing to report that the flame is still going when it tries to restart. I ordered a new igniter from Amazon but it was broken on arrival, so will try again.
 
"Even if I shut the heater and filter off for up to ½ hour, it will just go back to the Service Heater light coming on."

I wouldn't suspect the ignitor if you can shut the system down for a half hour and still get the same result. But, I have seen stranger things. BTW, have you looked at the board under the top as well as all the wiring inside to make sure it all looks normal? No chewed spots on the wires or corrosion on the board?
 
Yes, the board and wires all look as good as new. I installed the new igniter and get the exact same results :( Today I measured the resistance at the igniter when it was cool and it showed 0 ohms. I think it's supposed to be 50 - 500 ohms, so still not sure what's going on. Really wish I could fix this!
 
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