Old Raypak Versa 265b heater goes on and off when heating spa, but stays on when heating pool. Temperature sensor or Unitherm Govenor??


New member
Dec 7, 2020
Las Vegas, NV
Hi, I have an Old Raypak Versa 265b pool/spa heater that I hadn't turned on in over a year. I started it up the other day and it was fine, but heats the spa for about 10 mins then starts turning on and off every 5 mins. If I heat the pool with it, its stays on just fine, which leads me to believe their is an issue with the temperature sensor? Being that the pool is 20,000 gallons, so unless I run it it for 48 hours straight the water is never getting above 70, as compared to the spa which is heating up much quicker. Any advice on if it's most likely the temperature sensor or could it be something else like the Unitherm Governor or high limit switch?

Any help and/or suggestions would be greatly appreciated.


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

That type of cycling is often caused by low flow overheating the water triggering the HLS sensor.

When was the last time you cleaned your filter? What is your clean filter PSI and what is it now?

What type of pump and filter do you have? Please create your signature with details of your pool and equipment. IT lets us better understand what could be happening.


New member
Dec 7, 2020
Las Vegas, NV
Hi, thanks Allen. I updated my profile. I have a A.O Smith 1.5hp pump and a Pentair 150sqft cartridge filter. I just cleaned it the other day. I'll check the pressure tomorrow and get back to you, as i just glued in some new pipe to replace an old portion and am waiting for it to dry thanks!
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