Haywood heater clicking sound

[Dmiller6]

we bought a house with a pool and a Hayward gas heater. It is heating the water and seemed to be working correctly but about 1 hour after starting began making this clicking sound.

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Is this just normal sounds or something wrong?

 

[1poolman1]

No, it is not a normal sound. Try to see if the sound is loudest at the inlet/outlet header. Without being there, it sounds like too much water is bypassing inside the header. All heaters have a built-in bypass to allow the correct amount of water to enter the heat exchanger and them mix with cooler water returning to the pool. The small amount actually getting into the heat exchanger, if the bypass has failed, could be flash boiling, creating pressure that causes a sound similar to what is in your file.

 

[artellan]

My Hawyard H250 was making a sound like this today, right after I turned it on. I took out my skimmer sock (which was clean but potentially obstructing flow a little) and turned it back on and the sound went away. Not sure if taking out the skimmer sock was related or not.

But I was wondering if it was a similar issue to this thread, where the OP said the problem turned out to be his filter needing to be cleaned: Hayward Heater Clicking/Knocking

 

[Thorvald]

Likely the min. GPM flow switch inside the heater. Check your manual, it typically requires 40 GPM of flow. Normally on a Hayward there is an LED that will light up when there is not enough flow (interlock switches) and if that is in sync with that noise, you found it.

Another test is to speed up your pump (i.e. increase flow), remove any extra obstructions (filter bypass, socks etc) and see if noise goes away. If so, your right on the border of the switch spec, just slightly increase RPM's on pump (or clean filters) assuming it's a variable speed.