A leaking heat exchanger. Virtually every time. Most likely, if you remove the manifold, you will find that the tubes that are supposed to stick out about 1/2" - 3/4" from the mounting plate are corroded away. Sorry.What causes this kinda corrosion on these outside bolts of Pentair heater manifold case?
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It’s only 4 years old.Remove one bottom bolt to see if water pours out of the bolt hole.
How old is the heater?
How long does that normally take? A few years ago in the Texas freeze my heater was accidentally on for a few days. I was debugging a HLS error and saw my bolts are all rusted on the manifold. Trying to figure out what happened.I doubt your heater was killed by bad water chemistry unless you used Trichlor tablets in a feeder.
I suspect corrosive condensation from cold weather operation did it.
Heater Condensation - Further Reading
www.troublefreepool.com
My prediction is if you install another MasterTemp heater and run it the same way it too will leak in about 4 years.
Probably not unless the cell ran with no flow and filled the heater with chlorine gas and hydrogen gas.There isn’t a check valve between ic40 and the heater. Could that be an issue?
Yes.If water comes out does that mean the exchanger has failed?
Yes, turn the pump on and watch the hole.Should that be done under pressure?