HL2 Code on Raypak r206a

Poolnewb105

Well-known member
Apr 6, 2019
119
Ny
Hey guys, this season I've been getting an HL2 code on my Raypak 206a heater. I'm aware that this is because the outlet temperature is exceeding 135 degrees Fahrenheit. This happens regardless of the rpm that I set variable speed pump to. However I will note a high pitch squealing sound once the pump gets down around 1700rpms (only while the heater is running).

I read that the most probably causes aside from a defective HL2 switch (rare) are clogged burner tubes, damaged internal bypass assembly, or a defective unitherm governor. Replacing the governor looks pretty straight forward but replacing the bypass assembly and cleaning the burner tubes are probably outside my comfort zone.

Do you guys think the unitherm governor is most likely the culprit given the aforementioned symptoms or is there something more sinister at play here? Also, is there any way to test the bypass assembly without removing the header?

I will also note that this pool has a SWG and the pool chemistry is meticulously maintained.

Thanks for your time!
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
23,736
Northern NJ
Pool Size
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Chlorine
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Pentair Intellichlor IC-60
You just have to work through the possibilities from the easiest and least expensive part to the more complex fixes. No telling which one it is.

You get the HL2 when running your pump over 2500 rpm?

@ps0303 @Pool Clown
 

Poolnewb105

Well-known member
Apr 6, 2019
119
Ny
You just have to work through the possibilities from the easiest and least expensive part to the more complex fixes. No telling which one it is.

You get the HL2 when running your pump over 2500 rpm?

@ps0303 @Pool Clown
Yes I get it at 2600 and 2800rpm. I honestly haven't tried below 2600rpm for any length of time to see if I get hl2 but I know at lower rpm the heater makes a high pitch squealing sound almost like a kettle.
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
23,736
Northern NJ
Pool Size
35000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
Yes I get it at 2600 and 2800rpm. I honestly haven't tried below 2600rpm for any length of time to see if I get hl2 but I know at lower rpm the heater makes a high pitch squealing sound almost like a kettle.

That sounds like a bypass problem. The bypass is stuck open and too little water is flowing through the heater. At lower RPM the water is boiling and kettleing inside the heater.
 

Poolnewb105

Well-known member
Apr 6, 2019
119
Ny
That sounds like a bypass problem. The bypass is stuck open and too little water is flowing through the heater. At lower RPM the water is boiling and kettleing inside the heater.
Do you think it's a waste of money to replace the unitherm governor then?

Is there any way to test the bypass?

The heater is 12 years old so I'm not sure I want to risk taking it apart.
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
23,736
Northern NJ
Pool Size
35000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
AFAIK you have to open it up and take a look.

How old is the heater?

If you replace the unitherm governor you should be good for another few years.
 

Poolnewb105

Well-known member
Apr 6, 2019
119
Ny
AFAIK you have to open it up and take a look.

How old is the heater?

If you replace the unitherm governor you should be good for another few years.
The heater is 12 years old. Will changing the unitherm governor do anything assuming it's a bypass issue anyway? I'm not sure it's worth the trouble to remove the header and potentially screwing something up for a heater that old.
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
23,736
Northern NJ
Pool Size
35000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
Dunno. Hard to predict.
 

Poolnewb105

Well-known member
Apr 6, 2019
119
Ny
Would a defective unitherm governor also produce the kettle sound at low rpms? I'm considering taking the $50 gamble on the governor and if it doesn't work, just let it keep shorting out on high limit until the heater goes belly up.
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
23,736
Northern NJ
Pool Size
35000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60

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Pool Clown

In The Industry
Sep 5, 2008
2,187
Silicon Valley, CA
Both items are by-passes of sorts.

Internal by-pass is a water flow thing and it works the same if the heater is on or off. If working properly, it should compensate for the pump RPM.
Uni-therm gov works on water temp. If the the squeal stops when the water cools down (heater shuts off), i would start there.

More to consider:
Even though the U/G and the by-pass are relatively inexpensive, I would consider the age of the heater, especially if it is presenting with age related issues, mainly rust and corrosion, before investing time and money.
 

Poolnewb105

Well-known member
Apr 6, 2019
119
Ny
Both items are by-passes of sorts.

Internal by-pass is a water flow thing and it works the same if the heater is on or off. If working properly, it should compensate for the pump RPM.
Uni-therm gov works on water temp. If the the squeal stops when the water cools down (heater shuts off), i would start there.

More to consider:
Even though the U/G and the by-pass are relatively inexpensive, I would consider the age of the heater, especially if it is presenting with age related issues, mainly rust and corrosion, before investing time and money.

Thanks for the input. I would rather not take the header off because of the age of the heater like you said. The Unitherm Governor however seems like a pretty easy fix so I'd be willing to try that out.

The squealing is non-existent at low rpms with the heater off. In the event that the UG doesn't fix the HL2 code, is it ok to keep using the unit and letting it fault out on high limit every half hour? I mean it's still heating the pool, just slower because it keeps throwing the switch. But maybe I'm playing with fire (pun intended) relying on the Switch to operate properly every time?

In a perfect world, I'd be able to limp through this season and swap it out in the off-season. The heater lives out of the elements too for whatever that's worth.
 

Pool Clown

In The Industry
Sep 5, 2008
2,187
Silicon Valley, CA
You can try U/G replacement, but if it squeals even if the heater is not firing, its sounding like the mechanical by-pass is the issue.

Or you can get both parts, and leave them in the packaging until you get the heater disassembled without issue. That way, the parts are returnable if needed.

If you choose to run the heater as is, you are continually overheating the heater and subjecting the PLASTIC header to possible warping.

Then you will have a real project!
 

Poolnewb105

Well-known member
Apr 6, 2019
119
Ny
You can try U/G replacement, but if it squeals even if the heater is not firing, its sounding like the mechanical by-pass is the issue.

Or you can get both parts, and leave them in the packaging until you get the heater disassembled without issue. That way, the parts are returnable if needed.

If you choose to run the heater as is, you are continually overheating the heater and subjecting the PLASTIC header to possible warping.

Then you will have a real project!

To be clear it never sqeals when the heater isn't running. I was reading that this is actually quite common with Raypak heater (even when new) on low rpms so I don't think the squeal and the HL2 code are related.

I'm gonna try the UG and hope for the best. Is there any way to know if the bypass is working or not without removing the header? Any other symptoms?
 

Pool Clown

In The Industry
Sep 5, 2008
2,187
Silicon Valley, CA
Just so you are informed...

The lower you run the pump, the slower the water moves through the heater. The slower the water moves, the more heat that cannot be taken away from the heater (by the water). So IOW, you should at least run the pump at a speed that allows the internal by-pass to work, otherwise the temp is going to be higher making the HL2 more likely to trip. Of course, if the internal by-bass is broken, you could get noise at any recommended speed and the HL2 fault.

Does that make sense?
 

Poolnewb105

Well-known member
Apr 6, 2019
119
Ny
Just so you are informed...

The lower you run the pump, the slower the water moves through the heater. The slower the water moves, the more heat that cannot be taken away from the heater (by the water). So IOW, you should at least run the pump at a speed that allows the internal by-pass to work, otherwise the temp is going to be higher making the HL2 more likely to trip. Of course, if the internal by-bass is broken, you could get noise at any recommended speed and the HL2 fault.

Does that make sense?
Perfect sense. This is why I normally run the pump at 2600rpm when the heater is on since there is no sound at the level. The new UG doesn't arrive until Wednesday so I'm praying when I take it out and test it, it's faulty.

Assuming it is the UG, do you guys think it's safe to run the pool heater for the next 2 days and let it trip out on high limit or am I asking for trouble?
 

Poolnewb105

Well-known member
Apr 6, 2019
119
Ny
Ok guys, I received the new Unitherm Governor and tested it against the old one. It looks like the old one opened up about 60% and the new one opened up to 100% when submerged in hot water. The pool heater sound at low rpms was also gone. Do you guys honestly think that a UG that opens up an additional 40% is enough to prevent a high limit switch being thrown?

For what it's worth, the top of the unit is extremely hot. Is it supposed to be this way? There is a vent stack attached so I'm talking about the rest of the top. Thanks.
 

Poolnewb105

Well-known member
Apr 6, 2019
119
Ny
Measure the exhaust temperature with an infrared temperature gun.

Since my exhaust exits through a vent stack and out about 10ft above that, should the vent stack jacketting be a similar temp? Also, how hot should the surrounding areas be?

Do you think that the new UG opening another 40% would prevent the HL2 code being thrown?
 

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