Heater temperature spike


New member
Jul 25, 2021
I just bought a brand new Pentair master temp 250 after my pool guy couldn’t figure out why my old heater temperature kept spiking. I purchased a new heater and then the same problem persisted. my pool heater would fire up then start to heat for a few seconds then the temperature would spike up over 100 which would shut the heater off so the heater would only heat for a couple of seconds before shutting off and then the cycle would repeat over and over.

I ended up replacing my two year old pump with a brand new pentair pump so now I have a new master temp heater and brand new pump. I just fired it up today and the heater is doing the exact same thing. Pool guy thought it was a glow issue but now I have all new equipment. Help!


Gold Supporter
TFP Guide
Jul 21, 2013
Northern NJ
Pool Size
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
Welcome to TFP.

That temperature spike is usually a sign that your heater is getting insufficient water flow.

Post pics of your pool equipment and plumbing.

Please create your signature with details of your pool and equipment. Doing so will save everyone a lot of time asking you about what models you have, type of pool, pool volume, etc.

Your pool guy has cost you a lot of money with no results to show for it.

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