[SOLVED] Heater won't start

Speedo

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LifeTime Supporter
May 4, 2011
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My pentair minimax 100 isn't firing up. The control knob (mechanical) does click when it reaches the point where the heater should be kicking on. I don't see any blinking LEDs, it appears there is nothing happening beyond the mechanical thermostat knob clicking when it should be turning on. In my mind it appears the control knob has power and is working properly, but beyond that nothing is working. No LEDs blinking, nothing. I did find that the main board had a loose ground, pushed that on tightly, no difference. Any ideas?

TIA
-Aaron


PS -- Will take pics if that helps encourage responses :mrgreen:
 
Re: Heater won't start

Spark ignition -- the only idea I've come up with so far is possibly there is a bad fuse. I noticed in the manual that there should be an inline fuse. I'll snap some pictures and take a look at it soon.
 
Re: Heater won't start

First place to start is to check the power source (120 volt). The click you hear in the thermostat is he mechanical contacts "making" the circuit. That is only one of several switches that need to close to complete the circuit. You will need to verify that all switches/sensors are completing the circuit. If that is the case then it could possibly be the board. Was the heater running recently?
 
Re: Heater won't start

Unfortunately I wasn't able to take any pics or check to see if there is an inline fuse to replace. It was raining, I will get to it tomorrow night.

The heater was running overnight on Friday. I did notice in the manual that a (multi)volt meter can be used to troubleshoot by checking various connections. I could easily pick one up and try to narrow it down, but I can't say that I'm familiar with how the system works.
 
Re: Heater won't start

Strange, last night I got it working. Tried it with pump on high to make sure there was enough flow (it has always run on low speed before) and it worked. I did notice a rattling noise coming from inside the heater where the pipes connect. I then test it on low speed and it's working, no rattle.

On high speed the psi goes up to around 18, which is normal. Low is around 5 psi.
 
Do NOT adjust the pressure switch. They are set at the factory for the specified PSI settings and if you mess with it, you could cause the unit to stay fired when the pump is shut off. This is very dangerous. If you suspect the pressure switch is bad you can easily test it and then replace it.
 

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A pressure switch is set for the manufacturer so that if the pump is not pumping water, the heater is supposed to shut off. It's a safety that every heater I have ever touched going back 10 years has had one.

The only time a pressure switch needs to be or ever has been adjusted is because the pool sat up higher than the equipment and the downward water pressure is enough to keep the switch open when the pump shuts off.
 
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