I have installed a Geo heat pump with a standing column water source. The unit will be constantly pressurized @ house pressure with the water control vlave on the discharge side. When wiring the water valve, can I wire it to the 24V transformer in the unit and the "Y" wire in the unit, or do I need to get a seperate transformer and a relay and use the "Y" wire as a signal to close the relay and have the valve actuation curent come from the external transformer controlled by the relay? Thanks
Wiring As Ami stated - wire to unit. If wiring a slow opening valve, it needs to interrupt the compressor call from the t-stat until the valve is open. If quick opening, they both can come on at same time. When pairing with domestic systems, it is important the valve has enough torque to close against the differential pressures created.
I agree with the advice to wire valve directly to Y1, though with one caveat Be sure the valve doesn't consume an inordinate amount of control power. 24 Vac control transformers have a limited amount of power available, perhaps 50-75 Volt-Amps (VA), and some of that is needed for thermostats, unit control board, reversing valve pilot, and contactor relay. Valve VA rating up to 10 should be OK; much more than that and it might be a good idea to check amperage on the 24 Vac hot, typically red, coming off the control power transformer.
