I have a Honeywell TH6320R1004 and am trying to set it up to work with a second transformer (just added a Taco ZVC403 to an existing Taco SR503). The second transformer was needed to power the zone valves which was too much for the SR503). I'm hoping someone familiar with these Honeywell thermostats can help out.
The problem I'm having is that I can't get the call for heat from the Honeywell to register with my Taco ZVC.
The Honeywell is set to "2H / 1C heat pump" mode and had been using the Y terminal to call for heat. I reconfigured the R jumpers to split R+Rc from Rh. The Rh is now powered by the new ZVC. The circuit in question is in green in the attached image. Note, the Relay's 1 & 2 terminals are always closed in heat mode. The Relay Coil is energized in cool mode disabling the circuit, and I have the thermostat set to "O/B terminal controls valve in cooling".
I get 24v across the thermostat Rh and Y terminals whether or not heat is being called for. I also get 24v across the ZVC zone terminals.
Is the Y terminal closed with Rh when heat is called for in 2h/1c mode? I've also tried the G terminal (fan) with no luck. Just looking for what Equipment terminal on the thermostat is energized with a call for heat.
Any idea what the problem is? Thanks in advance for your help.
UPDATE I also removed power to Rh and then tested ohms across Rh and Y and Rh and G when calling for heat. Nothing. I tested across Y and G and found continuity. It made me want to jump Rh and G and see if Y is then energized when there is a call for heat, so I did and IT WORKS - the circuit is energized and the ZVC received a call for heat on the Honeywell zone.
Seems like a crazy workaround, but perhaps I'm not the first to discover this. Now the questions:
- What is the right way to do this.
- With O/B terminal controls valve in cooling mode, how else can I get the Honeywell to call for heat? There does not seem to be any Equipment terminals on the thermostat which energize on Call for Heat.
- When in cooling mode, will Rc (from one transformer) now connect to Rh (the 2nd transformer) via G and create a short? The circuit on Y will be open so nothing should happen on it.
- Anything else you can think of?