SW Open Raypak Heater (2024)

Raypak's design of the high limit switches on the residential models just isn't good.

I bought new HL sensors, applied new thermal paste (literally used Thermal Grizzly CPU thermal compound), and put adhesive underhood engine insulation all around where the sensors are located. It hasn't tripped HL2 since.

dfwnoob said:

Raypak's design of the high limit switches on the residential models just isn't good.

I bought new HL sensors, applied new thermal paste (literally used Thermal Grizzly CPU thermal compound), and put adhesive underhood engine insulation all around where the sensors are located. It hasn't tripped HL2 since.

See Also

Raypak Pool Heater Troubleshooting: Troubleshoot Your Pool Heater with Experts

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In hindsight. Do you think you needed anything besides the insultation ? I don't understand why there was no recall or such...

I do not see where you reported on the results of a Overnight Chlorine Loss Test

evanwellens said:

In hindsight. Do you think you needed anything besides the insultation ? I don't understand why there was no recall or such...

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My theory is that the thermal compound may play a larger role. I think what happens is that the heat rising up out of the combustion chamber is what physically heats up and trips the HL switches. That area of the heater gets boiling hot during extended runtimes. The thermal compound allows the sensors to let that heat get transferred into the header more effectively. The high temperature wrap may have helped some.

ajw22 said:

I do not see where you reported on the results of a Overnight Chlorine Loss Test

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evanwellens said:

It's been crazy raining here , battling algae all summer

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The algae you are battling is why you have filter and flow problems.

Fix the algae problem.

ajw22 said:

The algae you are battling is why you have filter and flow problems.

Fix the algae problem.

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It's almost impossible with all the rain and our pool is surrounded by tall trees. That said the filters are barely dirty , the chlorine is on the high side and the pressure is low ( high would be clogged filters. )

dfwnoob said:

My theory is that the thermal compound may play a larger role. I think what happens is that the heat rising up out of the combustion chamber is what physically heats up and trips the HL switches. That area of the heater gets boiling hot during extended runtimes. The thermal compound allows the sensors to let that heat get transferred into the header more effectively. The high temperature wrap may have helped some.

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Very interesting , thank you for your insights.

evanwellens said:

Toggling the heat on and off a few times , seems to clear the issue ( temporarily until next startup ) . I have a hot tub and had a similar problem , pressure switch failing and heat would not turn on. Going to give replacement a try.

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Ok that didn't work. Not only that but the replacement switch didn't work at all where the old one did.