Raypak - High 2 limit fault - checked unitherm governor, now what?

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Ok, replaced the sensor, heater seems to now be working properly, except it is saying the pool temp is 52 F when it is actually more like 76.

What does this mean? Faulty sensor? Installation error?
 
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No, the temp sensors on Raypack's have not been adjustable for what seems like ages, and you cant accidentally bump them and throw them off. At this point i would say either the sensor or the board.

A while back Raypak started using a two sensor sensor, to make them more accurate, hense no user adjustment. The board monitors both sensors and will detect if the two begin to drift apart in resistance reporting, and at that point you would get a sensor error not an erroneous temp reading. AND, sensor failures usually go in the upward direction. So, im afraid the board may be interpreting the resistance reading wrong.

Wait, did you get a genuine Raypak sensor?
 
I'm thinking it's not the board because with the old sensor I just pulled out I was getting accurate temp readings, I would just get the sensor failure error a minute or so after the heater fired up.

So maybe I didn't get a genuine raypak sensor? This is what I got, probably too cheap to be raypak sensor? Though there are many recent reviews that said it solved the problem for my same model.

Amazon.com: Raypack 009577F Temperature Sensor Iid Units: Garden & Outdoor

Amazon.com: Raypack 009577F Temperature Sensor Iid Units: Garden & Outdoor
www.amazon.com
 
It's amazon so no cost to return and order a new and have it by Friday if bad sensor seems like a reasonable possibility.
 
Just a bit more info @Pool Clown .... ran the heater for a few hours today and it seems to be operating normally except of course, the display continues to show the pool temp at 52F (up to 55 with 2 hours of heat) . Strangely(?) the quality on the LCD is also worsening.

Notable to me that the old sensor reported the heat accurately but caused "sensor failure" error and heat shut down while my new sensor reports the heat inaccurately but allows the system to run. Notable..... but I don't know what it might mean.

Bad sensor out of the box or board problems?

Time for that tech visit?
 
Amazon listing says from Raypak, so that's good...

If you have the time to wait for a new one, try that first (cheapest route). Something to try while you are waiting.
The center connector is common (BLK). and the two green wires are the two sensors (resist-, or thermist-ors). You can check the resistance between black and one green and then black and the other green, their readings should agree. Then set the two sensors (old and the new) side by side and let acclimate for 15 or so min. Everything being equal, all four connections should agree. If so, logic says the board, or a component there on.
 
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Replaced temp sensor again and get same result- things run fine but water temp is reported about 25 degrees low. I also got the high limit 2 fault so that problem remains as well.

Thanks for all your help with this Pool Clown, definitely appreciate learning more about my heater and where I can DIY (or not).

Time to call a tech. Will report final results here.
 
Pauls234 said:
Replaced temp sensor again and get same result- things run fine but water temp is reported about 25 degrees low. I also got the high limit 2 fault so that problem remains as well.

Thanks for all your help with this Pool Clown, definitely appreciate learning more about my heater and where I can DIY (or not).

Time to call a tech. Will report final results here.
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Enjoyed this thread so far. What ended up happening with the tech?
 
bryantdr said:
Enjoyed this thread so far. What ended up happening with the tech?
Click to expand...

Unfortunately, not much, but thanks for asking. I do owe an update.

With all of the increased demand for anything pool related, the only tech I could get to come out was from Leslie's and that took a several weeks. He did not seem particularly experienced working on heaters and was heavily reliant on calling the boss to walk him through things.

I told them, in advance, my issue was the temp sensor error and the hi-limit 2 fault.

He did replace the temp sensor (which I did as well) and now it is reading the temp correctly, so I believe that the sensor that I purchased on Amazon was not actually a genuine part, despite it being labeled as such. So, at least that is fixed.

For the hi-limit 2 fault, the advice was to clean my filter and that should be fine. I told him that is not the issue, it faults periodically even when the flow is very high (which is almost all the time). He said he could replace the hi-limit, but wasn't sure it would do anything, and maybe the temp sensor replacement would fix it. There was no mention of inspecting the by pass or any of the other suggestions made in this thread so I did not feel like spending any more money on guesses.

So, essentially, I paid a few hundred bucks to fix something that I was able to fix on my own, but with a genuine part, and I also learned that not all people that work on pool heaters know much about them.

I would happily pay for an experienced tech to come and troubleshoot and fix my hi-limit 2 issue once and for all, but finding one that will come out, especially this season, has been a challenge.

I haven't sat out there and timed how frequently the fault happens and thus, how long the heater shuts down during times of extended heating, but it is still raising the temp by the same 2 degrees/hour that it always has, so it is not that disruptive.

At this point, I will be closing the pool within weeks so this has fallen well down my to do list. Perhaps I will make some calls late winter or early spring next year to try and set something up. Or, maybe in the off season I will spend a lot of time reading and watching videos on heater repair and then see if I can get @PoolClown24 or @ps0303 to hand hold me through further troubleshooting and I can learn something in the process.

Either way, I will report back!
 

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pgershon said:
Did you ever replace the hi limit switch itself too?
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I did not. I suppose that's the last thing I could try but I figured it wasn't the case as it's obviously opening and closing.

1 thing I will say is that the unit displays the proper water temperature while not in operation but when heating it displays about 5 degrees higher than it should be. I'm not sure if there's any correlation between this and the high limit tripping.

When I had the header off, the heat exchanger tubes looked perfectly clean so I'm at a loss. The heater is 12 years old at this point and we've had issues in the past with mice making nests by the burner box and chewing some wires (which have been repaired). I'm not sure how any of that plays into the overheating issue.
 
Sounds a whole lot similar to my story. My heater was a replacement put in in 2011. I have matching heaters for my pool and spa. The pool heater has been relatively trouble free, but the spa heater has really acted up. I have had many issues with the Jandy 6586 mini board, which sends calls for heat from the pool/spa controller to the heater. And typically my service people have replaced parts in the heater that were probably OK because they missed the real problem from the external device. This happened last year and this year again, and led to my replacing the board twice, the main gas valve twice and a transformer.

Somewhere between those parts being swapped out and my replacement of the temperature probe, the hi limit 2 started up. It comes on every 2 out of 3 days, usually right before the heater gets the temperature to its maximum setting (I have spa set to 107 because that corresponds to 104 at the spa - this is why I tried changing the temperature probe). The high limit error is cleared by my setting the unit to off and then back to spa at the heater switch itself (I get a message "press mode to restart"). After one reset, the heater gets to full temperature and I need not repeat until the next day (and the spa usually cools down to the mid 80s or even the 70s depending on temperatures overnight).

I tried changing the temperature sensor to correct the temperature difference as I dont like setting heater all the way to 107 (requires overriding the high limit of 104, but Raypak support says this is normal). When I put new sensor in, I needed plumbers epoxy to help seal the new probe because my adaptor (006714F) leaked when new probe went in (I was not prepared with a replacement part). I have a replacement (ordered after the fact) that I plan to install and wonder if this will help with the hi limit 2. I also have three parts on my list to try - the bypass, the unitherm governor, and the high limit 2 switch itself. I will report back if any of this fixes the issue.
 
pgershon said:
Sounds a whole lot similar to my story. My heater was a replacement put in in 2011. I have matching heaters for my pool and spa. The pool heater has been relatively trouble free, but the spa heater has really acted up. I have had many issues with the Jandy 6586 mini board, which sends calls for heat from the pool/spa controller to the heater. And typically my service people have replaced parts in the heater that were probably OK because they missed the real problem from the external device. This happened last year and this year again, and led to my replacing the board twice, the main gas valve twice and a transformer.

Somewhere between those parts being swapped out and my replacement of the temperature probe, the hi limit 2 started up. It comes on every 2 out of 3 days, usually right before the heater gets the temperature to its maximum setting (I have spa set to 107 because that corresponds to 104 at the spa - this is why I tried changing the temperature probe). The high limit error is cleared by my setting the unit to off and then back to spa at the heater switch itself (I get a message "press mode to restart"). After one reset, the heater gets to full temperature and I need not repeat until the next day (and the spa usually cools down to the mid 80s or even the 70s depending on temperatures overnight).

I tried changing the temperature sensor to correct the temperature difference as I dont like setting heater all the way to 107 (requires overriding the high limit of 104, but Raypak support says this is normal). When I put new sensor in, I needed plumbers epoxy to help seal the new probe because my adaptor (006714F) leaked when new probe went in (I was not prepared with a replacement part). I have a replacement (ordered after the fact) that I plan to install and wonder if this will help with the hi limit 2. I also have three parts on my list to try - the bypass, the unitherm governor, and the high limit 2 switch itself. I will report back if any of this fixes the issue.
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Please let me know if the high limit switch works.
 
I've been thinking about replacing my by-pass as well to see if that solves my hi limit 2 fault problem, but that might be above my skill level and have found it impossible to get a knowledgeable tech to come and service. I'll be interested if replacing the hi limit switch itself will solve this, but at this point, I've been living with it a couple of years, it has not gotten any worse, and still heats at about 2 degrees/hour so, while I make it a mental priority in the spring, once things get rolling it falls down the list, and then before I know it, fall is approaching so I put it off until next year!

Please keep us all posted and I will do the same!
 
Pauls234 said:
I've been thinking about replacing my by-pass as well to see if that solves my hi limit 2 fault problem, but that might be above my skill level and have found it impossible to get a knowledgeable tech to come and service. I'll be interested if replacing the hi limit switch itself will solve this, but at this point, I've been living with it a couple of years, it has not gotten any worse, and still heats at about 2 degrees/hour so, while I make it a mental priority in the spring, once things get rolling it falls down the list, and then before I know it, fall is approaching so I put it off until next year!

Please keep us all posted and I will do the same!
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I know exactly how you feel. I'm not about to replace the heater until necessary.

Replacing the bypass assembly is ridiculously easy. The included instructions even tell you the proper tightening pattern and torque. Believe me, I'm an expert at breaking stuff and this I had no issue with. I will say that my old bypass assembly spring was a little stiff but it was still functioning properly. The old unitherm governor was also functioning but not as well as the new one. Replacing the 2 parts has helped the heater but has not completely solved the problem.

The heater used to make a high pitched squeal at lower rpms and no longer does so. This is how I know replacing the 2 parts has helped. Inclined to just let it do it's thing til it either starts leaking or stops heating. It's 12 years old so I'm not really willing to invest any more of my time in it. If you change out the high limit switch and it works, perhaps I'll reconsider. I believe there are 2 of them (hl1 and hl2).
 
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Have not posted for a bit. On another thread, it was suggested I insulate the heat shield above the high limit sensors. I have done that, as well as change the sensors and poly thermal paste on them. Heater now works without issue 50% of the time, and high limits out just before hitting max temperature the other half. I inspected UG again and it looks pretty corroded. Ordered a replacement. I have a new bypass too but have not installed. I was going to do that today, but could not figure out how to get the screws out. What is the right tool? Its tight for a wrench/plier and my socket wrench set was to shallow. I ordered a deep socket wrench set from Amazon
 
pgershon said:
Have not posted for a bit. On another thread, it was suggested I insulate the heat shield above the high limit sensors. I have done that, as well as change the sensors and poly thermal paste on them. Heater now works without issue 50% of the time, and high limits out just before hitting max temperature the other half. I inspected UG again and it looks pretty corroded. Ordered a replacement. I have a new bypass too but have not installed. I was going to do that today, but could not figure out how to get the screws out. What is the right tool? Its tight for a wrench/plier and my socket wrench set was to shallow. I ordered a deep socket wrench set from Amazon
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Swapped UG today. Old one looked pretty corroded
 

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