Monday, 22 May 2023
The pool heater has been acting up. Again. Sometimes it comes on, other times not. Today the heater wouldn’t come on at all. With a hard failure maybe I can figure out what’s going on.
Front cover off
View after removing top
I followed the 24V power. Transformer OK. Fuse OK. Firemans switch OK. Power to pressure switch. Power from pressure switch. Power to Ignition controller. And that’s where it stopped regardless of the switch and temperature settings. I disconnected the Thermister and checked its resistance. Resistance was where it should be for the current pool water temperature.
The temperature control board/assembly – the board and the potted electronics it is connected to with a ribbon cable – is bad. That is a newish board/assembly, replaced about 11 months ago because the original unit was acting flakey. To verify I replaced the new unit with the old unit which I’d kept. Heater came on.
Grumble. I put the heater back together and ordered another replacement because I know that the old unit may work today, but is not 100% reliable. I hope the next board lasts longer. They are expensive.
Sunday, 28 May 2023
Installed the new temperature control board. The job was quick because I didn’t bother changing the thermister. The existing thermister checked out fine. Pool heater works again. Too bad it’s been too cold/windy to use the pool.