topic Re: Nest Generation 3 and 2-wire Honeywell R7284 in Nest Thermostats

Nest Generation 3 and 2-wire Honeywell R7284

Nathan_S — Mon, 27 Mar 2023 17:44:55 GMT

I recently moved into a house with forced air oil heating, and I wanted to use my Nest Generation 3 with it. There were only two wires running to the old thermostat (which used AA batteries): red and white (RH and W, with a jumper between RH and RC). I connected RH and W to the Nest, without the jumper (according to Nest's instructions).

After hooking it up, the Nest gave me Low Battery errors (wouldn't connect to Wi-Fi, Nest App not working). The Nest hadn't been used for awhile, so I pulled it off the wall, recharged it using a USB cable, and connected it back up. It worked fine for about a day, then it showed Low Battery errors again. The thermostat is still turning heat on/off, but the battery isn't charging, and the App and Wi-Fi won't work.

After some digging, it appears I'd need to get a Nest Power Connector (in lieu of having a C wire pulled). This is fine - but there's no terminal labeled C on the controller: a Honeywell R7284.

This thread: https://diy.stackexchange.com/questions/241814/is-it-possible-to-add-a-c-wire-to-a-honeywell-r7284-oil-primary-control-current and the manual it refers to: https://jacksonsystems.com/wp-content/uploads/2020/04/R7284-Installation-Manual.pdf seem to show that terminal 2 is the same as C. But there was no follow-up confirming if this worked or not. According to the manual the voltage across 2 and 3 should be ~24VAC. Mine reads 28VAC. What I don't know - is what the Nest Power Connector is expecting, and if it's safe for the Honeywell controller and Nest equipment to connect it this way.

The only thread I've found in this Community with a similar controller: https://www.googlenestcommunity.com/t5/Nest-Thermostats/Nest-Thermostat-C-Connector-with-Oil-burner-and-AC-Unit/m-p/116728 isn't applicable, since we don't have the fan control relay, AC unit, etc.

I'd appreciate any help on the subject. If I can safely use terminal 2 as C - great! If I need to call in an HVAC technician - happy to do so. Thank you!

- Nathan

Re: Nest Generation 3 and 2-wire Honeywell R7284

Nathan_S — Fri, 31 Mar 2023 16:23:50 GMT

I tried hooking up the Power Connector using terminal 2 as C. Completely failed. After a few hours, the Nest's battery fully drained to the point where it just shut off. So I put back our old AA-battery powered Lux thermostat, and relegated the Nest to a drawer. Next time we have our scheduled furnace maintenance, I'll ask our technician about it.

Re: Nest Generation 3 and 2-wire Honeywell R7284

zoeuvre — Sat, 08 Apr 2023 16:59:01 GMT

Hi there,

I’m sorry to hear about your Nest Learning Thermostat situation. I see that your control panel has the non-standard labels of T, T, 3, 2, and 1 which means that your system is proprietary.

Proprietary systems aren’t compatible with Google Nest Thermostats. However, some proprietary systems can be rewired by a pro installer to be compatible.

Let us know if that helps.

Thanks,

Zoe

Re: Nest Generation 3 and 2-wire Honeywell R7284

Jake — Tue, 11 Apr 2023 18:36:30 GMT

Hey Nathan_S,

I wanted to check in and see if you managed to see Zoe's post. Please let me know if you have any questions from here. I would be happy to assist, and make sure you are good to go.

Best regards,
Jake

Re: Nest Generation 3 and 2-wire Honeywell R7284

Nathan_S — Tue, 11 Apr 2023 21:46:44 GMT

Hi Zoe, Jake,

Thanks for the replies. We'll look into it with our furnace technician.

- Nathan

Re: Nest Generation 3 and 2-wire Honeywell R7284

Jenelyn_O — Wed, 12 Apr 2023 18:13:56 GMT

Hey Nathan_S,

Thanks for keeping us in the loop. It sounds like a plan. Please keep us posted.

I appreciate your help, Zoe and Jake.

Best,
Jenelyn

Re: Nest Generation 3 and 2-wire Honeywell R7284

Markjosephp — Sat, 15 Apr 2023 20:56:40 GMT

Hello Nathan,

I'm checking back in — how's it going? Have you managed to reach out to an HVAC technician?

Regards,
Mark

Re: Nest Generation 3 and 2-wire Honeywell R7284

Jake — Tue, 18 Apr 2023 19:13:50 GMT

Hey there,

I wanted to check in, and let you know that I will be locking the thread in 24 hours.

Best regards,
Jake

Re: Nest Generation 3 and 2-wire Honeywell R7284

Nathan_S — Tue, 18 Apr 2023 21:27:24 GMT

Thanks for the follow-up. It's fine to lock this thread. Installing the Nest is low-priority right now, so we haven't gotten back to it.

Re: Nest Generation 3 and 2-wire Honeywell R7284

Jake — Wed, 19 Apr 2023 18:20:48 GMT

Hey Nathan_S,

I will go ahead and lock the thread at this time. If you have any trouble when installing your device, please feel free to create a new post. I am more than happy to assist.

Best regards,

Jake