Taco ZVC oddity

ChasMan

I have 5 zone valves and a DHW circuit. The DHW is on a pump, 2 zone valves are on a zvc 403 controlling one pump and 3 zone valves are on a zvc 404 . When the heating circuit for dhw is triggered I close the priority zone tstat circuits on both zone valve controllers and that puts them into priority. I have the end switches on the priority zones shorted out. It works fine on AC power. When I run it on Inverter power however, the four zone controller is forever in priority. I have to remove the end switch jumper and the thermostat wires or turn priority to off to get it to work the zone valves. Very odd. I'm thinking it's picking up ghost power from the other controller. I dunno why but there is some voltage on those wires. Any ideas?

Jamie Hall

For starters -- check that your generator is properly grounded.

ChasMan

It's a solar inverter. I didn't wire it up but it appears to use the regular house ground. Everything else in the house works fine. Computers, Fridge, Router, Ovens, Laundry, Dishwashers.  Digital streaming devices, Stereo.. all these things are loaded with complex microprocessors and switching circuits. I'm going to add another relay I guess to separate the two priority circuits but it's still weird. And sometimes the end switch indicators won't shut off at all on the inverter.

STEVEusaPA

What kind of thermostats are you using.

ChasMan

It's a mixed bag. One is a 2 wire white Rodgers. Then I have two  olderTekmars and one new Tekmar. There is also a Honeywell thats running the AC and one heat zone. The Honeywell is powered off when the inverter is on backup since it's on the AC system and not part of the backup.