What's this blue buildup on my heater's unitherm governor?

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MostlyCanuck

MostlyCanuck

Bronze Supporter
Mar 19, 2021
186
Toronto, Ontario, Canada
Pool Size
15000
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
Have had issues with this brand new heater.
Supposed to function at 30GPM, and never did until at least 45GPM.
At that speed (45GPM - 2100RPM), it would work but making a loud howling/whaling noise.

Jandy today sent a tech. He did two things.

Changed an internal pressure valve. He said the one heater comes in is for 5PSI and he installed one that works at lower pressure. That seems to have solved my first issue where the heater wasn't firing at 30GPM but needed much higher speeds.

He also changed the unitherm governor, which he thought was the culprit for the howling/whaling noise. All seems good for now.. time will tell.

What's strange to me, is that the unitherm governor valve was heavily coated in some bluish residue - see pictures below. Tech thought it was calcium... I was surprised because (a) my calcium is well within levels and my chemistry is always well balanced (see PoolMath logs in my profile if helpful)... and (b) this is a new pool and heater has been in use for just about a month.... and this seems like a LOT of buildup.

What do you think this buildup is / whats going on?!

C12EE831-A077-4F73-887D-0D9D18D03EBC_1_105_c.jpeg
 
Btw - I just went to check the chems my PB added when the pool was first opened last month - and there was nothing blue in colour left over. Could this be PVC glue/cement that was used for plumbing that made its way through pipes, passed the filter and ended up being stuck on the thermal regulator valve? I can't think of what else this might be..
 
Did they add anything with copper ? Sequesterants / shocks / etc at startup ? A lot of their go-to stuff has copper and blue leftover anything is almost always copper.
 
Newdude said:
Did they add anything with copper ? Sequesterants / shocks / etc at startup ? A lot of their go-to stuff has copper and blue leftover anything is almost always copper.
Click to expand...

Now that you mention it, he did add a metal sequestrant indeed, if I recall correctly. Dumped a full container in it, before I asked him what was there to sequester in clean new drinking water and tried to stop him! He also added half bottle algicide and some oxidizer shock. The only other thing was salt, of course.

What I find shocking is the amount of it. It's a lot considering that whatever was put in the water was once (not cumulative over many years)... and how is my cartridge filter not blocking that?
 
Metal particles are usually smaller than the filter material. Hence the need for poly fill contraptions to remove it once it’s unsoluable-d (in soluabled ?). Lol.

Anywho the goop is clearly thick enough to trap it. If my thoughts are in the right direction. Hang tight for more. :)
 
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Another thought…. How did you fill ? Is it well water up north or are there higher than normal metals in the municipal water ? It could have come from either of those and would explain the need for sequesterant at the beginning too.
 
Newdude said:
Another thought…. How did you fill ? Is it well water up north or are there higher than normal metals in the municipal water ? It could have come from either of those and would explain the need for sequesterant at the beginning too.
Click to expand...
It's municipal drinking water. Full chem analysis published here, if relevant... doesn't mean anything to me.. and i'd imagine it's consistent with whatever standards for drinking water there are in large north american cities.... https://www.toronto.ca/wp-content/uploads/2021/05/8e4a-DS21-0106-DrinkingWaterAnalysis2020-AODA.pdf
 
The report indicates anywhere from 3.3 to 1.0 ppm orthophosphate with an average value of 1.8ppm. On a phosphate test that would 1,800ppb . That’s a very high level of phosphate for a pool and can lead to calcium phosphate scaling in a water boiler. My guess is the blue color is likely a calcium phosphate scale with some copper mixed in it from the heat exchanger which would give it a blue’ish color. If you pulled off the header block on the heater you might see a thin layer of scale on the internal pipe surface.

Just keep your pool water balanced properly and maybe check the thermal regulator in another few months to see how it’s holding up.
 
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JoyfulNoise said:
The report indicates anywhere from 3.3 to 1.0 ppm orthophosphate with an average value of 1.8ppm. On a phosphate test that would 1,800ppb . That’s a very high level of phosphate for a pool and can lead to calcium phosphate scaling in a water boiler. My guess is the blue color is likely a calcium phosphate scale with some copper mixed in it from the heat exchanger which would give it a blue’ish color. If you pulled off the header block on the heater you might see a thin layer of scale on the internal pipe surface.

Just keep your pool water balanced properly and maybe check the thermal regulator in another few months to see how it’s holding up.
Click to expand...
Thx Matt - sounds like there's something in my local water I might always have to battle then perhaps.. (the original fill water came from nearby municipality on a truck, so G-knows what's in there)..

Besides checking this every few months, is there something I should do to "neutralize" this? Does my local water chemistry mean my thermal regulator is permanently doomed needing a replacement so frequently? Hard to believe or else every pool owner in Toronto would have blueish goop screwing up their heaters... I wonder what else is at play?

What boggles my mind most of all is that this is a brand new pool opened a month ago.... if the calcium phospate / copper naturally in the system is so high leaving such a thick residue after a month.... what are my long term prospects and what's a smart solution to this?
 
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MostlyCanuck said:
Thx Matt - sounds like there's something in my local water I might always have to battle then perhaps.. (the original fill water came from nearby municipality on a truck, so G-knows what's in there)..

Besides checking this every few months, is there something I should do to "neutralize" this? Does my local water chemistry mean my thermal regulator is permanently doomed needing a replacement so frequently? Hard to believe or else every pool owner in Toronto would have blueish goop screwing up their heaters... I wonder what else is at play?

What boggles my mind most of all is that this is a brand new pool opened a month ago.... if the calcium phospate / copper naturally in the system is so high leaving such a thick residue after a month.... what are my long term prospects and what's a smart solution to this?
Click to expand...

I think you will be fine. I actually believe it’s all caused by the startup chemicals the PB added. If he dumped in both metal scale control and algaecide as well as a non-chlorine shock, that chemical stew can possibly cause precipitates to form. Also, the internal surface of the heater is bare copper metal so it can actually release some copper into the water (tiny amount) until a surface passivation layer forms. Metal sequestering chemicals can exacerbate the issue.

Long term I believe you will be fine and you will not need to worry about the thermal regulator. Just check again whenever it’s convenient or maybe wait until the spring if you plan to close the pool soon. It’s highly unlikely you’re going to need to change it again.
 
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JoyfulNoise said:
I think you will be fine. I actually believe it’s all caused by the startup chemicals the PB added. If he dumped in both metal scale control and algaecide as well as a non-chlorine shock, that chemical stew can possibly cause precipitates to form. Also, the internal surface of the heater is bare copper metal so it can actually release some copper into the water (tiny amount) until a surface passivation layer forms. Metal sequestering chemicals can exacerbate the issue.

Long term I believe you will be fine and you will not need to worry about the thermal regulator. Just check again whenever it’s convenient or maybe wait until the spring if you plan to close the pool soon. It’s highly unlikely you’re going to need to change it again.
Click to expand...
Will do. Thx for your advice and for trying to make sense of whats going on..!
 
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