Connect Nest generation 2 thermostats to WaterFurnace geothermal units

[JeffP]

My Geothermal HVAC technician has installed the following Nest generation 2 thermostats on for the zones on my WaterFurnace geothermal HVAC unit.

first floor: 2 zones => 2 Nest gen 2 thermostats on WaterFurnace HVAC unit 1

second floor + floor: 3 zones => 3 Nest gen 2 thermostats on WaterFurnace HVAC unit 2

2 zones on second floor + 1 zone in attic

The technician reports that the Nest thermostats "will not release the wire" - I am not clear on what he means by that. I will ask him to explain and provide the information when he replies.

What I see is:
first floor: the HVAC unit 1 continuously cools regardless of what the thermostats set points are. To stop the unit from cooling I switch the HVAC unit 1 off at the main breaker panel.. The technical has replaced the zone. control board with a known zone board that works and see the same results.

second floor + attic: the HVAC unit 2 does not cool the attic off at all, but instead trigger a zone in. floor 2 to cool for an extremely long time, so long in fact the that zone is super cooled - meaning room temperature set point is 78 F, but room cools to <~ 72 F.

Both HVAC units are WaterFurnace HVAC Envision units built in ~2008.

WaterFurnace wants to sell him a device to reprogram their board. At this time the technician is not will to buy the programming device. I asked the technician details on the programming device, but he has not replied.

Any advice or suggestions are appreciated.

Would upgrading the Nest generation 2 thermostats to a newer generations such as generation 3 resolve the problem.

All 5 thermostats are wired in the following manner.

Thank you for your time and help.

[EdwardT]

Hi JeffP,

Thanks for reaching out and I'm sorry to hear that you're having an issue with your Nest Thermostat. I'd love to know more about this and I have a few questions:

• What does the display show when it's supposed to stop cooling?
• What's the make and model of your zone board?

Looking forward to your response.

Thanks,

Edward

[JeffP]

The geothermal HVAC technician tried to 2 different zone boards. Both boards showed the same issue.

The Nest generation 2 thermostats (there are 2 thermostats on separate zones) both indicate that the cooling has stopped - blue background disappears and returns to normal background. Overtime you can see that the actual room temperature continues to drop.

1. WaterFurnace original board. I do not know if. they make the zone boards themselves or use a subcontractor.
2. recently bough. io HVAC controls.
I have pictures of both boards. I am not sure how to send you pictures of the boards.

[JeffP]

[JeffP]

above is original WaterFurnace zone board
below is io HVAC control zone board

[EdwardT]

Hi JeffP,

Thanks for the added information. We'd like to know more about this. Please fill out this form so we could investigate further.

Thanks,

Edward

[JeffP]

Hi EdwardT. I tried filling out the form, but when I try to submit the form I keep seeing:
Refresh this page and try again. Sorry, there was a problem with the form.
I tried both using safari and chrome. I see the same result.
Is there an email address I can see the information to?

[EdwardT]

Hi JeffP,

Thanks for the update. I created a case for you. Our team will reach out to you via email to further assist you. Please keep your lines open as they may reach out to you anytime soon. Also, please be advised that this thread will be locked after 24 hrs.

Thanks,

Edward