Raypak 406A Scale and High Limit 2 Error!

[johnto]

Hi Everyone, I have been having some trouble with my pool heater for the past few weeks and wanted some advise. I currently have a Raypak 406a 399k BTU salt water pool heater.

I was running my pool equipment when I noticed low flow from the jets one day. I then started to notice some silver flakes/scale was coming out of the jets into the pool. I had the heater turned on and when I went to check the heater I noticed it was violently shaking and banging when it was on.

So I googled around and found this video. I am on well water which explains the scale buildup.

I opened up the heater and cleaned out the built up scale like on the YouTube video. Once I closed the heater back up everything was working great for around 2 weeks or so. I had proper flow and the heater was working as far as I knew.

I started the heater today that it took longer for my pool to heat up than normal. I automate my heater with a heater reader app and I was noticing the heater is cycling on and off on it's own. My heather reader app will say the heater is working then it will go to "Starting Heater" again then it will go to Heating once more.

I also noticed that the temperature on the raypak screen the temperature is a bit higher by about 3-5 degrees than on my heater reader app.

I also ordered a new unitherm governor as I checked the one I had in the heater and it seemed corroded, so I will try replacing this next.

I was also able to cycle through the fault menu and noted that there were 10 error codes all "High Limit 2 Error"

Finally. Before I noticed the heater was all scaled up I may have run it for 30min or so before I noticed it shaking and shut it off. Was it possible something else internally is broken? I feel when the machine was clogged up but still running and before I could notice and quickly shut it off that I may have overheated it.

Thank you

 

[johnto]

Just another thing. I took the front panel off of the unit and watched the heater for around 10-15 minutes. It would heat up fine and then it would throw the High Limit 2 error and then quickly shut off. It would then start back on by itself and start heating again until after 10-15 more minutes it would shut off again. I assume my heater reader app is continuously restarting the heater but it is throwing the HL2 Error. One thing I note though......is its doing it at around 88 degrees Fahrenheit which I think is a lot lower than others who have had this issue.

I am going to try to replace a new unitherm governor and Internal Bypass Valve this weekend and see if this does the trick.

 

[ajw22]

From RayPak Heaters - Further Reading

Things you can try...

• replace both high limit sensors and add thermal paste
• replace unitherm governor
• replace internal bypass
• add a heat shield

Some folks have added a heat shield above the HLS sensors. This thread describes how the high limit fault was fixed by insulating the header around the sensors.

 

[johnto]

Yes I will be replacing the uniterm governor and I bought the internal bypass to replace as well. For the internal bypass it came with two springs a silver one and a red one. Which one do I use for my 406A? I specifically have the P-406A EX-X Curpo Nickel 399k btu heater for a saltwater pool.

 

[ajw22]

See which spring comes out with the old bypass.