I am hooking up two water to heat exchangers with fans. I need to know if I can wire the fan relays in parallel with the zone valves, so the fans start when the zone valves open.
I am using time delays for the fans but know how to wire them, I just want to know if the relays can be wired and triggered at the same time the zone valves are opening.

Thanks

I don't see why not as long as the supply wire is large enough and rated for the full load amps. The isolation relay with time delay is the way to go. Your on the right track.