minimax 400 pool heater only 'power' light illuminates


New member
Aug 26, 2016
Flower Mound, TX
I have a minimax 400 pool heater and I'm only getting the power light to light up. I've tried shorting the TPROBE circuit to at least get the TSTAT light to come on, but that doesn't work which has me thinking about either the board or the transformer. I'm getting 28 VAC on the secondary side of my transformer and wondering if that is enough to fry my control board. Output is supposed to be 24 VAC. Not sure what the voltage at the SPA power switch terminal is supposed to be, but I'm reading 18.2V at the spa terminal.
Kinda weird, so if I'm looking at the board and I turn on the SPA power switch, I get no lights or anything, nothing happens except my voltage goes to 0 from 18.2 VAC on the SPA terminal.

If I have the SPA switched on and my meter on the SPA terminal, I read 18.2 VAC, then when I plug in, or short the TPROBE:
(1) the voltage goes to 0
(2) I hear a click and the TFUSE LED and HITEMP LED flash and go out.
Power to the board remains at 28 VAC

Any ideas???
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