I have a taco 557-G2 valve to allow water to flow through my climatemaster heat pump.
After about three years the valve allows some water to leak by all the time. This is the second valve to do this. After taking the valve apart I can't find anything wrong. Its clean and the seats seem to be in good condition and the spring is very strong. Water pressure is 50 psi.
Any sugestions ? Are there better valves out there that will do the same job ?