Nest thermostat - boiler issue

[Declanmcmahon18]

hi,

I recently had a nest thermostat installed buts it's making my boiler turn on and off a few times before it reaches the target temperature?

This never happened with my old thermostat - boiler stayed on until it reached the set temperature.

Could it be that the nest isn't wired properly? It surely can't be a coincidence that it started happening on the same day the the nest was installed.

My boiler is an "ideal classic ff360".

Appreciate any views you may have.

 

[stem]

If a Nest is wired in wrongly it won't work at all. The Nest is simply an 'on' and 'off' switch that turns the boiler 'on' and 'off' as required to maintain the set temperature. If it's doing that, the wires go to the correct places.

Boilers usually have greater capacity than the radiators they are connected to, so depending on how your particular boiler is designed it may be that the boilers internal thermostat is simply controlling its heat output and switching it on and off. If it fired continually the water would actually boil. If your Nest is connected by Open Therm it's a little different, but not that many boilers are. (sorry not familiar with your boiler)

You say it's a recent installation. The Nest is a 'learning thermostat' so it may just be learning how early it can switch off and the radiators will still hit the required temperature and may just need a few days to settle down.

 

[Declanmcmahon18]

Thanks Stem for the quick response.

Nest is fitted with 10 days now, could it still be learning?

Could the extra firing up of the boiler cause damage to the boiler if this was to continue? It seems to stop and start about 4 or 5 times before it reaches the target temp?

 

[Dan Robinson]

Probably the TPi beddng in or working.

 

[Declanmcmahon18]

Thanks for your comment Dan.

I’m not an expert though, could you expand a little more please?

Is it an issue that it keeps stopping and starting?

 

[Dan Robinson]

Sorry I had a typo now corrected


Google TPi and its operation.

 

[stem]

Nest is fitted with 10 days now, could it still be learning?

They can take some time, and it may take longer if you fiddle with it and don't let it settle.

Could the extra firing up of the boiler cause damage to the boiler if this was to continue?

Some think it will, others not so much. It all depends on the operating cycle of the components used in the construction of your boiler. Electrical components such as solenoids and relays can have specified life cycles in the range of 100,000 to over a million operations.

As the questions you are asking are product related and would be better referred to the technical help desks of Nest and Ideal.

 

[MeldrewsMate]

The TPI output will be turning the boiler off 'early' to try to prevent overshoot of the target temperature. The Ideal Classic is an old school boiler with simple fixed speed fan and fixed gas rating (of 60,000 btu/hr in your case). Stopping and starting it, whilst increasing the risk of component failure, is not as perilous as doing the same to a modern boiler.
The closer temperature control from TPI means that you can set the thermostat slightly lower without feeling the discomfort caused by the hysteresis on an old thermostat, which would have been typically about 2C.

I hope this helps.
MM

 

[McCombi]

Could just be your boiler thermostat is set a bit lower than it was previously and is coming up to temp before nest set temp is reached.

Is the nest in same place as old one was?

Maybe the old stat wasn’t readings temperatures bang on ie degree or two out, maybe the nest isn’t calibrated properly.

I have an older nest v2 and it’s way off, I’m sitting freezing in my living room when it’s reading 20degrees

 

[Declanmcmahon18]

Thanks for all the comments.

It seems to have evolved a bit again.

Now the boiler runs for 20 mins but then turns off and on every minute or so as it tries to get close to the target temperature. It's a long way way the target temperature when it starts behaving like this.

any ideas or suggestions as to why it's behaving like this?

 

[McCombi]

With that boiler, if happening as frequent as that, it may not be nest related at all. Get a registered gas engineer in to look at boiler.