I've had my pool for a couple of months now, only been using it for a couple of weeks. The first weekend, everything worked fine, the heater heated & controlled the temp just fine. Last weekend, it would heat up, but after several minutes there would be a violent cavitation noise, and the heater would shut off on high temp, even though it was no where close to control temp.
Today, the heater only runs for a few seconds, before it shuts itself down on high temp, even though the water doesn't have time to heat up at all.
I figured the noise and violent cavitation meant there was something in the pipes, even though the flow through the return jets do not show any signs that there is a restriction. I disassembled the pipes, going to and from the heater, and found nothing. I even pulled out the check valve and found it to be intact & operational.
Does anyone have any other ideas that I could check?