So I opened up the pool a couple of weeks ago. All seemed fine. Fired up the heater - no issues. Fired up the hot tub - no issues. Last weekend, had a bunch of people over. Hot tub was on for several hours at 98 degrees. Then was on 102 for another hour. When the heat was turned off, the valves were reset to circulate the pool water. For some reason, there was a sound of rushing water on the ground, the unitherm governor cap and governor were on the ground. It appears the threads in the header are partially stripped. I was able to jam the plug and governor back in, however, I can only operate the pump in a limited way without the plug blowing back out. Specifically, if I set the valves so that the water returns only though the spa jets and the Polaris outlet it's fine. If I turn it to go through the floor system or just the Polaris (without leaving the spa returns open, it blows off again. Pressure readings when it is running are less than 20psi (normal). My question is - what would have caused it to blow out (and strip the threads on the header)? Assuming the reason that it now comes out is because if the stripped plug, what about epoxying the plug in (since I'll ultimately need to replace the header anyway)? Any thoughts are appreciated!