Loud low noise from Sta-Rite SR333NA

[mpr5231]

My Sta-Rite SR333NA was installed in June, replacing an eleven year old unit of the same model. It has worked great all summer. Last night, I was outside when the heater fired, and it's making an awful noise. Turned it off, unplugged it overnight. Plugged it in the next day, and here is what happens: heater seems to boot normally as far as LCD sequence. Blower starts fine. But when the heater fires, it makes this odd loud sound - low, loud, kind of thumping, almost like a subwoofer being overdriven - with a faint grinding noise heard intermittently. No error LED's light up, it just keeps going. The water from the outlets is definitely being heated. But the noise doesn't stop- I let it run for about five minutes, then shut it down as I was worried about causing further damage.

Any ideas? I called my pool guy, but haven't heard back. I'm in Upstate NY so a lot of people are closing their pools right now.

Also - any experience with the Sta-Rite warranty process? My pool guy installed the heater, but I ordered it from poolsupplyworld.com. Again, it's barely three months old.

Thanks for any help!

 

[OldPoolMan]

Its the water being over heated. That usually means that the internal bypass, the flow disc, or some other obstruction is the problem. Do you have an external bypass? At any rate, it's a flow issue.

 

[ps0303]

If it is a broken bypass inside the heater, it's a loud popping, hammering type of sound. The unit usually shuts itself down then as it over heats. Also, it could be a bad thermal regulator as well. Similar issue and sound. You can remove the old regulator, and temporarily run the unit without. As you are running it with out, using a pair of pliers, hold the other regulator over the exhaust heat and see if it opens like it should when it gets hot. If it fails to open, you have your problem child. Also, if when you go to remove the regulator, if is gets stuck it could be hanging up on a broken internal bypass. Maybe you could record it and share with us.

Yes, make sure you don't have a valve turned wrong and thus starving the heater of water adequate water flow.