I have a hydronic system with T87 thermostats and V8043F zone valves. I just bought an RTH6580WF thermostat and I want to replace one of the T87s with it. I tried to follow the directions but my setup is different from the "standard" Honeywell setup so that didn't work. I then contacted Honeywell tech support India and got nowhere with that. All the guys there could do is work with a standard system and couldn't suggest how I might get things to work in my system.
So I wired it up like I thought might work and made progress - at least the thermostat powered up and I set it up on WiFi and was able to access it remotely. The only problem was that it doesn't work as a thermostat. That is, you change the temperature setting and it doesn't turn the zone valve on (or off). That's the history. Now on to what my setup looks like. I drew up a crude diagram of my system.
One initial problem was that since the old system only required two wires, one for R and one for W, I would need to get another wire for the C wire that Honeywell said was needed. Luckily, the wire that goes to the thermostat had 6 wires and 3 went to R and the other 3 went to W. So at both ends of the wire, the thermostat and the zone valve/transformer, I broke things up into 3 sets of 2 wires instead of 2 sets of 3 wires. Then I hooked it up as the Honeywell documentation said I should and the thermostat did not power up. That's when I contacted Honeywell tech support and got nowhere. So I hooked it up like I thought might be the correct way and as I said, it powered up but didn't act as a thermostat. The second attachment shows how Honeywell said to hook it up and then how I hooked it up. (The upload is not allowing me to upload more than 1 file so unless it starts working again, I'll just have to explain the wiring). I tried again and still no luck with the upload.
Honeywell said to just leave the wiring the same - transformer C to thermostat W, transformer R to zone valve Tr, and zone valve Th to thermostat R and then connect transformer C to thermostat C also. With that setup the thermostat did not power on. My wiring was transformer C to thermostat C, transformer R to thermostat R and zone valve Tr, and zone valve Th to transformer W. As I said, that allowed the thermostat to power up.
I don't know enough about the innards of zone valves - or the new WiFi thermostat too for that matter - to know what needs to be connected to what to get this to work. I have a suspicion that I may need to use the Th/Tr terminal on the zone valve but I wouldn't know how. The Honeywell tech support seemed to indicate that I should connect R & C from the transformer to R & Rc on the thermostat but then they couldn't tell me how to hook up the zone valve to the thermostat. Any help would be greatly appreciated. Thanks.
So I wired it up like I thought might work and made progress - at least the thermostat powered up and I set it up on WiFi and was able to access it remotely. The only problem was that it doesn't work as a thermostat. That is, you change the temperature setting and it doesn't turn the zone valve on (or off). That's the history. Now on to what my setup looks like. I drew up a crude diagram of my system.
One initial problem was that since the old system only required two wires, one for R and one for W, I would need to get another wire for the C wire that Honeywell said was needed. Luckily, the wire that goes to the thermostat had 6 wires and 3 went to R and the other 3 went to W. So at both ends of the wire, the thermostat and the zone valve/transformer, I broke things up into 3 sets of 2 wires instead of 2 sets of 3 wires. Then I hooked it up as the Honeywell documentation said I should and the thermostat did not power up. That's when I contacted Honeywell tech support and got nowhere. So I hooked it up like I thought might be the correct way and as I said, it powered up but didn't act as a thermostat. The second attachment shows how Honeywell said to hook it up and then how I hooked it up. (The upload is not allowing me to upload more than 1 file so unless it starts working again, I'll just have to explain the wiring). I tried again and still no luck with the upload.
Honeywell said to just leave the wiring the same - transformer C to thermostat W, transformer R to zone valve Tr, and zone valve Th to thermostat R and then connect transformer C to thermostat C also. With that setup the thermostat did not power on. My wiring was transformer C to thermostat C, transformer R to thermostat R and zone valve Tr, and zone valve Th to transformer W. As I said, that allowed the thermostat to power up.
I don't know enough about the innards of zone valves - or the new WiFi thermostat too for that matter - to know what needs to be connected to what to get this to work. I have a suspicion that I may need to use the Th/Tr terminal on the zone valve but I wouldn't know how. The Honeywell tech support seemed to indicate that I should connect R & C from the transformer to R & Rc on the thermostat but then they couldn't tell me how to hook up the zone valve to the thermostat. Any help would be greatly appreciated. Thanks.