rvhippo wrote:
What I don't understand is that one can send 40-50 psi of water or air through the valve during normal operation or winteriztion, but if I want to just release some trapped water, the valve can break so easily.
It has to do with DIRECTION!
When you are hooked up to city water or blowing compressed air through your lines you are sending that pressure INTO the system. The small O-ring is situated and designed to handle that pressure.
When you push in on the check valve while your lines are pressurized with antifreeze, you are exerting that pressure in the opposite direction and sending liquid OUT of the system. This can grab the O-ring and dislodge it, causing the check valve to no longer operate correctly.
I learned all this the hard way and had to disassemble the FW intake and reseat the O-ring, but it allowed me to understand how this all works.
Do as some others have said: first relieve the pressure in the system before you depress the check valve. Or get a manual pump and pump antifreeze through your City FW intake from the outside of the camper.
