SW Open Raypak Heater (2024)

So I'm back to this problem , more and more frequently now. Cleaning baskets and filters always fixed the issue before , but now we just did the filters 2 weeks ago and the pressure is normal , flow appears normal, no bubbling . Heater wont start sw open. We also get hi limit fault as well , since we've gotten the heater. I know folks say it's a flow problem , but there is no bypass and this is a 2 hp pump, puts out a lot of water. I'm at a loss what to check next ? Any ideas , getting cool and need the heater to not be ou tof commision.

Thanks !!

Hi limit fault is a known problem. Some thermal insulation around the high limit sensors usually fixes it.

Read RayPak Heaters - Further Reading

What is your other problem?

Remove the cartridges from your filter and see if it clears the SW OPEN error.

If so, clean or replace the cartridges and do a Overnight Chlorine Loss Test

evanwellens said:

So I'm back to this problem , more and more frequently now. Cleaning baskets and filters always fixed the issue before , but now we just did the filters 2 weeks ago and the pressure is normal , flow appears normal, no bubbling . Heater wont start sw open. We also get hi limit fault as well , since we've gotten the heater. I know folks say it's a flow problem , but there is no bypass and this is a 2 hp pump, puts out a lot of water. I'm at a loss what to check next ? Any ideas , getting cool and need the heater to not be ou tof commision.

Thanks !!

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Be sure there is no damage to the pressure switch or wiring, its located on the in/out manifold behind the top removable panel.
How old is the heater? Some had an issue with the High Limit 2 switch that some insulation could solve.
Could be the internal bypass or Uni-Therm regulator causing the hi-limit to trip as well.

ajw22 said:

Hi limit fault is a known problem. Some thermal insulation around the high limit sensors usually fixes it.

Read RayPak Heaters - Further Reading

What is your other problem?

See Also

Raypak Pool Heater SW Open Code - Fix FluxRaypak heater "Rollout SW Open"“Water sw open”. Raypak 266 digital.

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Yes the hi limit is a nuisance , but clears and resets. I do have it on my todo to find an insulation solution, just Leary that causes some damage if the temp is legit too high. SW Open is the other problem.

1poolman1 said:

Be sure there is no damage to the pressure switch or wiring, its located on the in/out manifold behind the top removable panel.
How old is the heater? Some had an issue with the High Limit 2 switch that some insulation could solve.
Could be the internal bypass or Uni-Therm regulator causing the hi-limit to trip as well.

Click to expand...

I guess I need to find a exploded diagram to determine the location.

The Hi Limit sensors still work as designed for protection with the external insulation on them.

The external insulation keeps other heat from causing them to trip prematurely.

evanwellens said:

I guess I need to find an exploded diagram to determine the location.

Click to expand...

Look in the Installation Manual.

evanwellens said:

I guess I need to find a exploded diagram to determine the location.

Click to expand...

Remove the top panel above the inlet/outlet manifold (the plumbing side of the heater) and it is right on top to the left. Looks like a mushroom.

Do a Overnight Chlorine Loss Test

ajw22 said:

Look in the Installation Manual.

Click to expand...

will do thanks

ajw22 said:

Do a Overnight Chlorine Loss Test

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What does that indicate ? Chlorine has been pretty steady all summer, I shock when needed and keep the chlorinator filled every 2 weeks.

wireform said:

Oclt will eliminate the fact or prove you have algae even if the water is crystal clear.

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

evanwellens said:

Is there any chance adjusting the pressure switch a 1/4 turn might help ? Cleaning filters weekly is getting old quick

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Running your heater with inadequate pressure and flow can damage the heater and pipes.

Read Heater Flow Switch - Further Reading and check the Raypak Installation Manual on the pressure switch adjustment range or if you should replace it with a flow switch.

Is there any chance adjusting the pressure switch a 1/4 turn might help ? Cleaning filters weekly is getting old quikc

ajw22 said:

Running your heater with inadequate pressure and flow can damage the heater and pipes.

Read Heater Flow Switch - Further Reading and check the Raypak Installation Manual on the pressure switch adjustment range or if you should replace it with a flow switch.

Click to expand...

Thank you for your reply. So this heater has been running 5-6 years and this problem only came up recently, and frequently despite constant changing of filters ( actually came up once before and those filters needed to be changed and the pool filter pressure was high) . Also occurs when we turn our Polaris on. It's intermittent and seems to be at the edge of functionality , but becoming a real headache. I'd estimate the pool water level is 2-3 feet below the base of the heater, so it sees to fall within guidelines. So if a minor adjustment to the sensor is too risky , what do you think about just replacing it ?

evanwellens said:

Just another observation , recently the heater has been making a moaning noise on occasion. Again on my todo to deep dive this problem , hoped it could wait until the season ended.

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My heater will do this if I forget to switch the pump to High. My old heater did the same thing. running mine on the high (2 speed pump) eliminates this.

Dan