cuda67racer2 wrote:Yes, was trying to use the bigger of the existing zones as the dump zone so it doesnt overheat the house while cooling down.
You can use a double pole relay . You won't even need the transformer . Just get a 110v coil . Something like this
This link is broken, either the page no longer exists or there is some other issue like a typo.
You would need a 8 pin base for this one but they are also available . Take your output from the high to activate the coil . Your zone valves can be fed from the secondary side in parallel with your thermostats . Dave