Pentair MasterTemp heater issues

[holts]

I have the Pentair MasterTemp natural gas heater for my in-ground pool (pictured below), I can not find a posting or any information on anyone having this same issue so I thought I would start here. When I turn the heater on and press the pool heater it will start up and heat for a little while, (never consistent on how long it will run, sometime a minuter some time 15 minutes). The heater will then randomly change to 'spa' from 'pool' and stop heating. There are no error codes on the screen, the service lights are not on, it shows the temp. of the water, and I have the set temp higher then the water temp. Any help would greatly appreciated!!

 

[ps0303]

So the unit is operated directly from the unit and no automation system?

Have you checked to see if anything has made a nest or something inside the unit? Removed the four front and rear panel screws and then in each corner under the top are wing nuts. Remove them and check to make sure nothing is living there.

 

[holts]

Thanks, it is operated directly form the unit, no automation. I did take the front and back of the panels off and although a little dirty, no nests or piles of debris.

 

[ps0303]

Then I would possibly suspect that maybe the keypad membrane is going thus causing the unit to jump to spa. What if you set it to spa and set your temp?

 

[holts]

Thanks again, I did try that, but when the heater switches from Pool on to spa on, it will not function at all until I switch it back.

 

[ps0303]

It should function no matter which setting you choose. Can you adjust the temp up and down OK?