cancel
Showing results for 
Search instead for 
Did you mean: 
Replies are disabled for this topic. Start a new one or visit our Help Center.

Nest stuck permanently heating

Krisflynn89
Community Member

Hi

I have carried out all of the suggested troubleshooting including reset, factory reset, checking all wiring, operation of 3way valve and valve body already.

The problem has started 2 years after install and has worked fine up until now. Suddenly overnight the heating is stuck permanently on if there is power to the heat link. Even if I disconnect the thermostat the heating demand stays on. Weirdly, if I put the heat link to manual mode it then correctly calls for heat and hot water. Asking for heat and hot water from the app does not do this though. My best guess is there is a fault with the nest heat link that's resulted in it permanently demanding heat.

 

If I turn the power off the system then the 3 way valve resets but as soon as power is restored the valve is receiving a signal to move to the central heat position and then the boiler and pump all kick in.

 

Any ideas what to try next? I'm worried asking someone to come out and look at it will result in a tennis match between a 3 way valve issue and a Google nest issue which will only end up costing me money.

 

Thanks

Kris

1 Recommended Answer

Krisflynn89
Community Member

Hi 

I didnt agree with your diagnosis that the heatlink wasnt at fault - the relays were operating but I suspect there was some sort of internal  fault or short circuit meaning one of the relays were always closed or open allowing a permanent signal for heat. Over night I received an automated email saying that a problem had been detected and I was eligible for a new heatlink. An engineer has been to my home today and fitted a new unit and everything is working again as it should.

Seems odd that heat links are offering to be replaced - this happened entirely automatically. Reading a bit more online there are lots of heat links being replaced at the moment... a known issue with certain generation models?

Either way if you find there is a problem with heating or hot water and you have ruled out your own heating system then i'd check if you are eligible for a new heatlink unit!

View Recommended Answer in original post

8 REPLIES 8

AlexD
Community Specialist
Community Specialist

Thanks for reaching out to us here @Krisflynn89. I would be happy to try and assist. 

 

What would be best to try first, a test that is easy to do using the Nest app. Go next to the Heat Link and open up the Nest app, make sure to power everything back on.

 

1. Select the heating control and make sure that it is set to be off, screen black. 

2. Turn up the heating until the screen goes orange, heating on, and listen for a clicking noise.

3. Turn the heating off, display black, and listen for a clicking noise again.

4. Go to the hot water control side and tap on the cogwheel in the upper right corner.

5. In settings, toggle off the first option there to disable the schedule while we test, you can toggle it back on after.

6. Turn the hot water boost on and listen for a clicking noise.

7. Turn the boost off and listen for a clicking noise again.

 

Let me know what the results are after, if it clicks or not.

Hi there

The heat link clicks and makes the noise every time one of the settings is changed so sounds like relays are operating. Whilst I was changing the heating on to off and off to on the central heating remained on the whole time. Interestingly when the hot water was selected on the 3 way valve did move to the mid position for heating and hot water and returned to heating only when the hot water was turned off.

 

Rgds 

Kris

AlexD
Community Specialist
Community Specialist

Thanks for checking. Based on this behavior it seems the thermostat is working as expected. Each command from the Nest app is sent to the thermostat display, the thermostat display is communicating those to the Heat Link and it's moving the relays around with an audible click.

 

Based on this, I would say the behavior is most likely related to the heating system. Most probably the valve might need replacement or the wiring, though it could also be something else in the system. 

 

What I would recommend would be to get in touch with your preferred installer or a Nest Pro. Here is the link for the Nest Pro finder from our website. They can look over the whole system including the Heat Link and thermostat. 

 

If indeed they find something going on with the Heat Link or thermostat, although it seems very unlikely, you can ask them for a diagnostic report. It is basically a document with yours and their information as well as the steps they have taken and what they identified as the issue. If needed I can send you a template for one to the email associated with your account here, just let me know.

 

If the diagnostic report indicates the behavior is related to the thermostat, if it is still within warranty, we can look at a possible replacement. 

 

We can also do some further testing if you are comfortable in doing so or have someone that can assist you with it. We can do some continuity tests on the Heat Link with a multimeter. If you wish to try this, just let me know and I can send you the steps for it. 

OannaCG
Community Specialist
Community Specialist

Hi there, just checking in, did you manage to see our message above?

Krisflynn89
Community Member

Hi 

I didnt agree with your diagnosis that the heatlink wasnt at fault - the relays were operating but I suspect there was some sort of internal  fault or short circuit meaning one of the relays were always closed or open allowing a permanent signal for heat. Over night I received an automated email saying that a problem had been detected and I was eligible for a new heatlink. An engineer has been to my home today and fitted a new unit and everything is working again as it should.

Seems odd that heat links are offering to be replaced - this happened entirely automatically. Reading a bit more online there are lots of heat links being replaced at the moment... a known issue with certain generation models?

Either way if you find there is a problem with heating or hot water and you have ruled out your own heating system then i'd check if you are eligible for a new heatlink unit!

UanaC
Community Specialist
Community Specialist

Hello there, Kris!

 

I am sorry for any inconvenience, but I'm also glad to hear that everything is back on track at the moment. Is there anything else I can help you with?

 

Many thanks, Oana.

AlexD
Community Specialist
Community Specialist

Hi, just wanted to check in. Anything else I can try and assist with? If so, make sure to let me know.

AlexD
Community Specialist
Community Specialist

Hey there, I haven't heard from you in a while so I'll be locking this thread. If you have any new issues, updates or just a discussion topic, feel free to start a new thread in the community. Thanks, AlexD.