Heat Exchanger scale removal and probably more

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BG Woller

Member
Jul 13, 2019
14
Michigan
Hi folks I really need some help here. I'm thinking I may have a few issues but let's start with the most pressing issue. Last summer we had a repair man out to tell us why the heater (Raypak 266) wasn't working properly. Well he took a couple panels off and after breaking the thermostat which he never did replace he told us we needed a new heater. I am a very handy person so I asked WHY? He told me that the heat exchanger was plugged with scale. What he never told me or rather wouldn't tell me was HOW to remove the scale. I took apart the manifold and he was right. There was one tube that was almost clogged with scale. I managed to get it partially opened up and the heater worked fine all the rest of the season. New season rolls around and after getting the water balanced for Ph hardness and chlorine I fired up the heater. The poor devil ( 4 years old) started right up, got very hot than shut down. I shut it down and tried again a few hours later only to have the same issue. It will start up, run for 20 minutes or so and shut off. After an hour or so it will fire back up again but never long enough to really warm the pool up. I'm thinking the root cause is build up of scale in the exchanger but just how do I completely (or close to completely) remove the scale? I can remove the exchanger but I don't know what I can soak it in once there is flow.
I'm going out there right now to check my Unitherm Governor and the pressure bypass switches but since I replaced both just last summer I'm thinking it isn't going to make a difference.
Ideas please!!!! I'll be honest with you, I hate swimming but even worse I hate working on this beast that never seems to stop breaking down I need help please!
 
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Ok what I have found out is the UG was completely plugged up with pine needles. I cleaned those out and removed a bunch from inside the manifold. I have got to find out which clown pulled out the strainer basket. In addition there were several pebbles of lime rolling around there. I got them all taken care of but there is still a fair amount of scale built up on the exchanger tubes. Time to put it back together again
 
Welcome to the forum!
Sounds like you are getting somewhere in your heater repair. We have a few members with heater repair experience, hopefully one of them will chime in.
With all that scale, sounds like you are not managing the pool water chemistry very well. You should not get scale like that.
I suggest you read ABC's of Pool Water Chemistry and consider reviewing the entire Pool School eBook.
 
How did pine needles get into your heater manifold?? The heater should be after the filter and so there should be no debris getting into it....
 
He either got the needles through a filter cleaning where the elements were lifted out of the tank and the some of the debris went into the "clean water" port. Or the filter itself developed a hole and by-passed the debris. My guess is the latter.

If you have a Raypak, watch the second video. If you watch the first, you'll just get confused, completely different heater.

Just for info, the first part of that video shows (part of) the cause of the sooting he speaks of, NOT the scaling that he is addressing in the video. The source of the sooting here, if any, is not having the right vent cap on the stack(s) . Those caps do not let enough exhaust gases to pass through it causing an improper air fuel mix/burn in the fire box. And if both of those heaters are 407s, there may not be enough air getting into the room either. Just sayin...
 
I hate to have to report this but just a few day's after I posted these questions here Ma Nature rolled through and kicked our butt's! We lost a total of 33 pine trees so for the past few all I've been doing is yard cleanup, cutting down trees, trimming, burning, you name it we've been doing it. This week I'm hoping to bore out the heat exchanger to get that calcium/lime out of it but would it help if I were to soak it in some sort of solution to remove ALL that crud? Maybe CLR or even vinegar? What kind of acid should I use. The 1's video didn't say what kind he is using. I did review the 2nd video on scale removal but the producer never said what kind of "Burr" I needed to use. Can anyone help me there?
Also another issue has surfaced. Now when I turn on that $ sucking hole in the ground the jets are spewing a steady flow of very small bubbles. It slows down but never fully stops. It's now been 2 full seasons since I changed my filter sand out and I was going to do that anyhow this year...could my laterals be broken or cracked and in need of replacement?
 
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You really haven't told us very much about your pool - except that it has a Raypak 266 heater. Please fill out your signature with details of your pool equipment (make & model numbers), pool volume, interior surface, how you are chlorinating and what test kit you are using. Have a look at my signature and a few others to get an idea of what to include. This will assist us in better helping you without needing to ask about your pool every time.

If you are seeing bubbles coming out of your returns, you have a suction side air leak. Something isn't completely sealed, allowing air to be drawn into the suction side plumbing. Frist place to check is the o-ring on the pump lid - clean it and its mating surfaces, then lube is with silicone based pool lube.
 
I have a furnace/propane friend. I was telling him how my water heater for my house wasn't quite hot anymore. It uses a similar heat exchanger. The furnace keeps the tank hot and the house water goes through a worm inside the tank. He said scale was the cause and he would hook up a pump to both pipes and circulate muriatic acid through it to clean it out. He said the same would help my heat pump for the pool while we were at it. I imagine the heat pump would be easier because there is no copper to cut and sweat back together. Its on our project list but havent gotten around to it. It got warm out and scolding hot shower water became less of a concern. Will probably care again once the late fall is here.
 

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Pool Clown said:
Trying to chemically remove the scale can be tricky. I wouldn't advise it. You are better off doing the drill out method.
Click to expand...


My buddy just mentioned it as an afterthought while discussing the hot water heater. Now that I think about it specifically, could the exchanger be taken out and capped/filled like cleaning the SWG ? Or are there any issues that would make if different/not advisable ?
 
proavia said:
You really haven't told us very much about your pool - except that it has a Raypak 266 heater. Please fill out your signature with details of your pool equipment (make & model numbers), pool volume, interior surface, how you are chlorinating and what test kit you are using. Have a look at my signature and a few others to get an idea of what to include. This will assist us in better helping you without needing to ask about your pool every time.

If you are seeing bubbles coming out of your returns, you have a suction side air leak. Something isn't completely sealed, allowing air to be drawn into the suction side plumbing. Frist place to check is the o-ring on the pump lid - clean it and its mating surfaces, then lube is with silicone based pool lube.
Click to expand...
Darn it, that's one of the few things I didn't do when opening it this year! Thanks for the advice, I'm off to clean up the filter basket ring now
 
BG Woller said:
Darn it, that's one of the few things I didn't do when opening it this year! Thanks for the advice, I'm off to clean up the filter basket ring now
Click to expand...

How many gallons is your pool?
What is the model number of your Raypak heater?
What model is your Pentair pump?
What model is your Pentair filter? Is it sand, DE or cartridge?
What specific test kit are you using?
What type of chlorine are you using... liquid, tablets, etc? What is the percentage?

Add these items to your signature - be specific.

You may want to consider testing more than once weekly to help keep you pool water in better balance. This will certainly help reduce and/or eliminate your scaling issue. As was suggested above, read ABCs of Pool Water Chemistry and review the PoolSchool E-book .
 
Lets put aside the fact that to chemically remove the scale is not advised...

Why would you want to go to all the trouble?

You need to take the exchanger completely out of the heater to fill it with chemical.
You don't need to take it out, to drill it out, as shown in the video. You only have to take the I/O header and return header off. And there is no chemical to have to deal with after.
 
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proavia said:
How many gallons is your pool? Approx 44,500 if I've calculated it properly.
What is the model number of your Raypack heater? P-M266A-MN-C
What model is your Pentair pump? Superflo Model SF-N1-1A/340038
What model is your filter? Hayward Sand Filter Model #S244T
What specific test kit are you using? Name sticker is long gone, test chemicals are currently refilled with chemicals from Leslie Pools who I've quit buying from as they never have the parts I need in stock. "We can order that but it will take two weeks"
What type of chlorine are you using... liquid, tablets, etc? Currently using Leslie pools Jumbo tablets
What is the percentage? Sorry I don't understand this one


I've added this information to my signature also, Thank's
Also I checked my strainer "O-ring" per your instructions yesterday. It's shot and in need of a replacement. In addition the PVC glue has broken down around the pipe there so that need's repairing also. Again, Thank you
Click to expand...
 
After reading this thread I've determined the best course of action is to drill out the crud from the heat exchanger. Easy enough and awfully straight forward. This however leaves me with another question... Once I've gotten the beast running and maintain the pool chemistry properly will the remaining crud be broken down or will I have to be consider it a permanent resident?

Update on the bubble issue. It would seem that I've been successful in repairing the pvc as I no longer have a bubble machine at the far end of the pool. Thanks for that advice! I greatly appreciate it and so does my wife! Happy wife, happy life!
 
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