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Nest not starting heat for 1 of 2 zones

balaS
Community Member

I have a 2 zone system with oil burner, separate AC condensers and 2 separate forced air blower units. Both are on Nest. Both zones are wired exactly the same between the blower units and the thermostat. Zone1 doesn't seem to get power from the Rh wire and won't kick on the furnace when heat is requested. It can run the fan fine. Cooling also works like it should.

Sometimes it turns on when the zone 2  starts heat. Not sure it's related or means anything. Zone 2 turns on the furnace immediately for heat tho. I don't think it's a thermostat issue as I switched them between the zones and the same issue happens on Zone1. I've tried all the troubleshooting (resets, settings changes etc.) and Google support and so far nothing. I've played around with the Rc and Rh wires as well. 

Anyone had a similar issue? My search didn't bring up any similar issue. 

2 REPLIES 2

maedacortez
Community Specialist
Community Specialist

Hi Balas,

 

Thanks for reaching out. I understand that your Zone 1 does not receive power from the RH terminal and does not work properly, and I'm happy to assist you.

Before I can help, I need to ask a few questions to better understand the situation:

  1. What type of Nest Thermostat do you have?
  2. What is the error code or error message that your Google Nest Thermostat device displays?
  3. Could you please send me a picture of your wire labels and connections on your Zone 1?

I look forward to your response.

 

Regards,
Manuel

balaS
Community Member

For folks who are experiencing heat continuing to run past the set temperature or not starting after a higher than current temp is set on Nest, check the flow control valve. I'm using oil burner with forced hot air supplied by hot water. I had to replace the flow valve's control unit (the front part) but not the valve itself that's welded to the water pipe. It fixed this issue. My other issue was that when I set the Zone 2 (upstairs) to a higher temp then the zone1 (downstairs) would start up providing hot air. I think the zone 2 startup was somehow circulating the hot water for zone 1 as well and the sensor on zone 1 triggers the circulation fan. Just my theory but replacing the valve control made everything work like it should for the zone1 issue. I came across a YouTube video on this specific issue that helped resolve the issue. 

https://www.youtube.com/watch?v=o0KSvDBLgjs