I have a Pentair Minimax Plus 400 heater that is not starting up properly, somewhat intermittently.
When the switch is turned on, or the temperature control knob is turned up to call for heat, sometimes it will fire up properly, but sometimes it gets stuck before it actually fires.
When it does not fire properly, here is the sequence of events:
1) Switch turned to pool (or spa), or temp control know turned up
2) Click heard.
3) Thermostat LED lights (TSTAT) - so that seems ok
4) PowerMax fan turns on, AUX and PRESS LEDs light - so it seems that is ok
5) Heat LED never lights, and you do not hear the burners ignite, nor any clicking.
6) Service LED lights
Pool Heater 3b - PreFiring.jpg
The switch and circuit board have been replaced, and all wiring disconnected and the terminals cleaned, but the problem persists.
I did notice two scenarios where it seems to work properly.
1) If the heat has been on for a while, and I shut it off using the switch or the temp knobs (for a few seconds to few minutes) then turn it back on, it almost always fires up
2) the second scenario is, if I tap the panel that the controls are on, just to the right of the controls, it will almost always come on. I know that is where the gas control module (PN 073584) is located, so was wondering if that could be the culprit? I don't have to tap very hard, and usually once will do it, so am wondering if that module has any mechanical parts that could be "sticking"?
This makes me think it is an issue with the ignition circuit - either the control module or the ignitor.
Is there something else I should look at before replacing the gas control module (they are kind of pricey).