Versa Heater Makes Knocking Noise, Then Trips

[jacob_coulter]

I have an older Versa heater, and when I turn it on, everything seems to be working, then after about 3-4 minutes, it makes a knocking banging sound, then the "High Limit" light comes on.

Any idea what's going on?

Thanks for the help.

 

[pragmatic]

I have an older Versa heater, and when I turn it on, everything seems to be working, then after about 3-4 minutes, it makes a knocking banging sound, then the "High Limit" light comes on.

Any idea what's going on?

Thanks for the help.

Maybe low water flow ~ http://www.troublefreepool.com/heater-clanking-sound-t29212.html?hilit=heater clanking

 

[racket]

The versa heaters have a part called a unitherm governor they regulate the water flow through the heater to prevent condensation. If/when they fail they can obstruct the water flow causing the water to boil inside the heater. What model of versa is this?

 

[Pool Clown]

Maybe low water flow ~ http://www.troublefreepool.com/heater-clanking-sound-t29212.html?hilit=heater clanking

That thread also suggests a UG (BY Racket incidentally)
If i does it only briefly during start up, the UG could be just sticking from scale. If you replace it, you should be good.

 

[jacob_coulter]

Thanks for the help, much appreciated.

When I was getting some pool work done, I had a tech look at my heater and he said it was due to the spa pump having a bad impeller (which it did) he said everything would be fine once I replaced the pump (which I did) now I have this issue.

Is a Unitherm Governor something a DIY'er can handle, or is that best left to a technician? Any recommendations online on where to buy the part?

Also, any reason why they are so expensive when they look EXACTLY like an $8 automotive thermostat?

 

[ps0303]

The uni-therm governor is located just under the header, where the water enters and exits the heater. You should be able to access it pretty easily if things aren't rusted over. They are expensive becasue they have the Raypak name on them.