Nest 3rd gen with ideal istor?

15 Nov 2016
Reaction score
United Kingdom
i have an ideal istor boiler, and just got a nest 3rd gen thermostat.
Anyone know if these will work - the wiring on the istor is all over the place...
Sponsored Links
I guess the real question then is anyone managed to do this?
Spent the evening trying to fathom out the rats nest of wiring in this boiler... gave up for now.
I might be in over my head, but it seems like it should be simple, but the boiler installation manual has me a bit confused as the programmer that's built in doesn't feature on the wiring diagram?
And from what I can see the room stat sits on a switched live before the power enters the boiler but that really doesn't seem right either.
Might be a job for a pro, was hoping to save the £100 lol
Not many Eyesores left in the world...give it a few months and yours might expire too, then you can fit your Nest to something with easier wiring ;)
Sponsored Links
Yeah we just moved in so it was such a "lovely" surprise to discover how **** the boiler is.
As we're not planning to be here that long kinda hoping to avoid a new one, it's just had a new expansion vessel and PRVs as was chucking water out the discharge pipe. Seems free of the other major faults, so far anyway.

I'll be happy if I can get the nest working with it - finding where the damn cable comes in from the stat will be a happy moment lol
Or even fit it I place of the existing stat if you have mains nearby and can work hot how to connect it.

Seems a little overkill having a Nest with simple on/off control on the boiler.

The Nest II would have done the same thing and been a little cheaper!

I was only charging £84 to install an on/off Nest. Thought that was about the average.

The nest was free from my energy company and so not really worried about that. Ideal tech support say don't even try to connect it to the boiler... but stuff it I've got someone coming next week to do it anyway, I decided I can't be bothered trying to work it out myself.

Not sure what you mean about it being overkill? Surely all the nest ever does is turn it on/off - either in response to temp or schedule?
Did you manage to get the nest fitted? Just wondering if it was set up to control the hot water too or if that was left to the boiler's own programmer?

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local

Sponsored Links