Pool heater repair

[swamprat69]

I am an extremely handy retired HVAC service technician. This is my third pool in my lifetime. Recently my 400K BTU Hayward pool heater started leaking at the water header. I took it apart and order a new O-Ring/gasket. Cleaned all surfaces and installed new O-Ring/gasket. It still leaks! Do you have a recommendation for an RTV silicone sealant that I can use as an adjunct to the O-Ring /gasket in order to get the water header sealed. I inspected the heater when I took it apart and all other components still seemed serviceable. I am trying to avoid replacing the heater as I am retired and on a fixed income. I can't seem to figure out why the new O-Ring /gasket did not solve the problem, but there did seem to be a good amount of space in the inset when the new gasket was installed. Any help would be greatly appreciated.

 

[ajw22]

@ps0303 may be able to help.

 

[swamprat69]

Like I said, when I replaced the O-Ring/ Gasket, it fit in the channel of the header but did not seem to fill the channel. There was space in the channel on either side of the O-Ring/gasket. I was thinking that I might be able to use RTV Silicone sealant to fill in the space around the O-Ring gasket in order to stop the leak, but I am not sure of the temperatures that the header sees at the seal. Since there is water flowing through the header, they might not be that high of a temperature, but again I am not sure. The other components of the heater seem to be in good shape ( heat exchanger and cabinet) and I can do any repairs needed on the fire side of the heater.

 

[ajw22]

What specific model Hayward heater do you have?

 

[KDpoolguy]

I’d just assume it’s a H400 model? If you can clarify where leak comes from. Is it the header itself, meaning where the header meets the heater assembly, or from the bulkhead connections for the inlet/outlet? On my H300 there are 2 Plugs and then the bulkhead connections on the header itself.

 

[swamprat69]

It is an H400 and the leak is is between the header and the heater assy. where the O Ring is supposed to be sealing that connection. There are about 12 nuts holding the header on if I remember correctly. The full model # is H400IDL2BH and the replacement gasket that was listed for the header is HAXHOR1930.

 

[KDpoolguy]

Gotcha, that is frustrating! You did the right approach. Now I’ve got to think about this, whether silicone lube is the right addition to the o-ring to help seal the header to the heat exchanger assembly? Maybe someone can help confirm?

That’d probably what I’d to and be sure the bolts are torqued properly.

Maybe something to look at, I was thinking maybe automotive gasket maker around the mate point may be a Hail Mary also.
Otherwise (brace yourself), the header or the exchanger could have a small crack.

 

[swamprat69]

Was thinking about RTV silicone sealant...not silicone lube. Possibly high temp rtv silicone sealant. The leak is in more than 1 spot and comes out between the header and the heater. No observable cracks or deformation.

 

[ps0303]

The oring should fill the slot it is supposed to fit in. Then you use oring lube on it to keep it in place as well. If the oring is really loose, then you might not have the correct one. Also check top make sure the header is not reformed in any way due to excessive over heating, aka melting. If all on the header looks good, then you might have a bad or incorrect oring.

 

[KDpoolguy]

Funny I’m reading my response @swamprat69, as I’m now dealing with the same issue.

 

[swamprat69]

Turns out that the O-ring that I ordered was not an OEM part even though it had the correct Hayward part number on the package. Ordered another from another vendor and the one that I got was slightly larger than the first. Had to use a little silicone sealant to hold it in place while mounting the water header, but this one finally sealed. The unions for the Hayward water header were lots of fun with the extra fine threads that threaten to cross thread if not lined up perfectly square

 

[ps0303]

Use the correct o-ring lube and not silicone sealant. You should always be lubing up the o-ring when you replace it.

 

[KDpoolguy]

Turns out that the O-ring that I ordered was not an OEM part even though it had the correct Hayward part number on the package. Ordered another from another vendor and the one that I got was slightly larger than the first. Had to use a little silicone sealant to hold it in place while mounting the water header, but this one finally sealed. The unions for the Hayward water header were lots of fun with the extra fine threads that threaten to cross thread if not lined up perfectly square

You were spot on, the size and shape of the non-OEM oring was off. What an awful piece of kit. The OEM bypass kit has the correct gasket. It has an oval shape, meaning the circumference of the actual gasket material is like a flat oval shape.
Anyways, it’s all getting returned since I’m having to get an entirely new heater.