unitherm governor

Hello, I am not an expert, but am doing maintenance for a place with a Rheem/Raypack millivolt pool heater in the basement. The other morning I woke up to the sound of a flowing river along with the pump sound the other morning. Luckily I was able to shut it off before too much got wet. Luckily...

Unitherm Governor Plug blew out today, I was not around when in occurred. I tested the Unitherm Governor (UG) in a pan of hot water, it cycled open and appeared to function properly. What else could cause the plug to blow? I am debating purchasing a complete header kit, but what to make sure...