The solenoid on the outgoing water pipe on my heat pump doesn't work. It should shut the water outflow off when the unit shuts off. There is no electricity reaching the solenoid. Otherwise, the unit works just fine. I tested for current at various contacts. There are several switches, etc. that I'm not familiar with. Any thoughts as to what might be the problem? This is a vacation home and it's tough to get a repairman.