Pentair Minimax 400 heater problem

spartanduner · Jan 20, 2009

We have a problem with our Pentair heater. It was working 2 days ago and tonight it will not ignite and the service light is on. All off the lights are lit on the front panel except for the heat light. The manual states that this may be the thermal fusible link, but I bypassed the link and there was no change. Does anyone have any experience with this heater and have any advice on troubleshooting this problem myself? There has been no change in the water flow or gas supply since it last worked. Any advice is appreciated.

Thanks,

Derek

spishex · Jan 20, 2009

If you turn the power to it off and back on again, does the service light immediately come on or does it try to ignite first?

spartanduner · Jan 20, 2009

spishex said:
If you turn the power to it off and back on again, does the service light immediately come on or does it try to ignite first?

The service light immediately comes on.

spishex · Jan 20, 2009

Have you checked continuity across the high limits?

spartanduner · Jan 20, 2009

spishex said:
Have you checked continuity across the high limits?

No I did not check for continuity there.

I did open up the front panel and see that the IID got hot and melted. I replaced the IID and the fusible link (even though the original appeared fine) and the problem persisted. I then noticed that there are LED lights on the back of the circuit panel and that the one labeled PV was not lit. The others (T-fuse and Hi temp) were lit. I then checked for 24 volts and found that i had approx. 27.8 volts going into the circuit panel but only about 18 volts leaving it. Is this normal? where should I go from here and what would cause the PV LED not to be lit?

I have family coming to town on Friday to see our new house for the first time and I would love for them to enjoy the spa.

Thanks,

Derek

spishex · Jan 21, 2009

Hi-temp LED on means your hi limits are ok. Are you sure it says PV and not MV? Either way, that's a problem I've not encountered. Double check the wiring on your new IID and make sure everything is grounded properly, especially the gas valve. I'll keep shopping around for a better answer.

*Be sure you're looking at the LED's after power has been disconnected and turned back on. The LED may be on until the first ignition failure.

spartanduner · Jan 21, 2009

spishex said:
Hi-temp LED on means your hi limits are ok. Are you sure it says PV and not MV? Either way, that's a problem I've not encountered. Double check the wiring on your new IID and make sure everything is grounded properly, especially the gas valve. I'll keep shopping around for a better answer.

*Be sure you're looking at the LED's after power has been disconnected and turned back on. The LED may be on until the first ignition failure.

Turns out it was one of the hi limit switches. The Hi limit LED that I thought was lit was only half lit. As soon as I jumpered across the two hi limit inputs on the circuit board the LED got much brighter and the heater fired right up. I am going to get two new hi limit switches tomorrow (because they both are in pretty bad shape), and if I can't find them that quick at least I know how to hot wire it for the weekend.

Thank You very much for all of your help.