11-29-2023 02:47 AM
Hi Community - we have a 2-circuit (upstairs & downstairs) setup in our house, with 2 Nest thermostats managing 1 boiler.
Since a few weeks, our heating upstairs started behaving erratically. It took us a while to figure out that heating instructions supplied via the Upstairs Nest thermostat are being ignored by the boiler, unless the Downstairs Nest thermostat is supplying the same signal. In other words: Upstairs will only heat if Downstairs is also heating. If the Downstairs Nest switches off, the boiler will switch off, no matter what the Upstairs Nest needs. Weirdly, it is still possible to NOT heat upstairs while heating downstairs - if the upstairs Nest is set to cool, this is respected by the boiler, no matter what downstairs Nest is telling it.
Both Heat links are green. We brought a Nest guy out, who suggested it was a boiler problem, and then we brought in a Boiler guy who was sure it was a Nest problem.
Any wisdom here? Thank you so much!
11-29-2023 05:33 AM
Hi there and thanks for reaching our Community. I'm sorry to hear about your issue, but I'll do my best to help you out. Can you please tell me if for each thermostat, there is one Heat Link as well? Or both thermostats connected to the same Heat Link?
11-29-2023 05:41 AM
Hi, thanks for your rapid response! Indeed, each Nest has its own separate Heat Link. Both are green while the behaviour as described above happens.
11-29-2023 05:43 AM
Is there a controller somewhere in the heating circuit that may interfere with the thermostats, by any chance? Or anything on the boiler at all?
11-29-2023 08:23 AM
Hey - there is no other fancy heating tech in the circuit, although we have some smart home devices in the house.... But none of this setup has changed in the last 6 months so the Nest-boiler combo suddenly behaving badly doesn't seem to be linked to interference from other tech.
11-30-2023 02:15 AM
Can you tell us what type of heating system do you have. It's a combi or a system boiler?
11-30-2023 09:03 AM
Hi! It's an Itho Daalderop Base Cube.
11-30-2023 09:17 AM
Do you have the hot water on demand or you need a schedule for it?
11-30-2023 09:24 AM
On demand - or rather, within 5 seconds of demand 🙂
11-30-2023 09:28 AM
I want to do some tests to see how the relays in the Heat Link behave. Go next to the Heat Link and open the Nest app on a mobile device:
1. Select your thermostat to access the heating controls and make sure the screen is black, heating is off.
2. Turn up the temperature until the display goes orange, heating on, and listen for a clicking noise.
3. Turn the temperature back down until the display is black again, heating off, and listen for a clicking noise again.
Let me know what the results are.
12-01-2023 06:49 AM
Here are the results for my problematic upstairs thermostat, with the downstairs thermostat switched off:
* From "black" to "orange", I hear various sounds, followed by a click after 10 seconds. However, the boiler does not actually switch on.
* From "orange" to "black", I also hear a sequence of sounds, followed by a click. The boiler does switch off in this scenario when I've forced it on beforehand.
I hope this makes sense - thank you for your wisdom!
12-04-2023 06:55 AM
Hi there! Since the Heat Link clicks, it works as expected. In this situation, I would recommend a continuity test. For that you will need an installer with a multimeter. I also recommend calling or chatting with us so we can guide through the procedure so we can make sure we document it as well. And since the installer would be there with you, I advise to check on the valves.
12-08-2023 06:00 AM
Hi, I wanted to check in. Do you need any further assistance?
If so, make sure to let me know.
11-29-2023 07:28 AM - edited 11-29-2023 07:30 AM
We have a similar issue. Our downstairs Nest Learning Thermostat controls the upstairs and the upstairs Nest Learning thermostat controls the downstairs. This morning I could not get the heat to be lowered until I set it at 60 degrees. It kept showing orange until the number read 60. For the other zone, I had to push the number up to 75 before it read orange and the heat started up. We NEVER had an issue with the furnace responding with our former thermostats. Yes, they were older Honeywell units, but once we pushed the temp up or down it responded quickly in any zone. It no longer reacts and the setting the schedule for daytime and nighttime doesn't work either. I had a plummer who works with Nest devices come out twice to make adjusts on the boiler and it's been a month now and he will not return texts, calls and it seems he will not return. I don't know what to do.