Yet another Nest fitted with Vaillant boiler thread... :)

Hi all....

I think it's possible to fit a Nest to my Vaillant 828 Turbomax boiler but I'm pretty confused about the whole thing really and there are so many different threads about doing it, I'm even more confused.

I must say THIS thread is useful as it discusses fitting to a 824 boiler. Part of the problem or confusion for me though is that my installation doesn't have any room stat at all.... in fact it didn't even have any TSV's until I started dropping radiators off to decorate and replaced the valves or fitted new rads. Even so the vast majority of our rads have not form of heating control, except what is set at the boiler. Consequently I think we are using alot energy and not get optimum heating in our rooms.....this is where I thought the Nest might come in useful.

I have taken a few hi-res photo's from the installation manual and copied them to Dropbox HERE and looking at PAGE 27 it would appear I just need to wire into terminals 3, 4 and 5? I'd appreciate any advice on this please.

Also whats the best way to then set everything up.... leave the TSV's to max on and control from the NEST. Should the boiler temperature itself being increased or will this typically be running at a temperature beyond what the Nest would require to be produced in a room? I'm assuming the boiler timer will still be used and can turn everything off so effectively the boiler has three switches, the Timer, the Nest stat and the boilers own stat?

Sorry for the really basic/thick questions, but thanks in advance for any help offered.

Dan

Looking at the 2015 thread that I linked to above I think I understand it and by all account as I have nothing wired in already it should be easy to do.

Quoting @mikeyd
So, connect boiler 3 (live) to Heatlink L and 2.
connect boiler 4 to Heatlink 3.
connect boiler 5(neutral) to Heatlink N

If I can't loop in because the terminals are too small would a 2 or 3 terminal Wago connector suffice?

Yes those connections look good. I doubt you'll have a problem linking the Live to terminal 2 in the Heatlink unless it's very heavy cable.

Thanks Jack...

Hi,

im struggling with this installation as well dfarry. I think my boiler is the same as yours (pic attached with the old thermostat wiring in 3,4,5). Would you be so kind to share a pic of the connection from heatlink to your boiler? that will make my understanding of how nest is connected better and indeed may help other novices like me?

thank you in advance

I haven't actually bought or fitted one yet. I was going to buy one from Npower for £130 as I am a customer but they have increased the price to £160. Although still cheaper than the retail price it's still a lot of money to pay for a glorified switch.

In the meantime my boiler has sprung a slight leak on the what I think is the DHW inlet (the boiler pressure isn't dropping). I need to take the front off so I will have a look at the electrical connections then as well.

Hi again.... sorry it's been a while. In the end I got sidetracked with fixing the leak (it needed a new diverter valve) and then didn't bother with the Nest. But at the moment Screwfix are selling them for £149 with a free premium (£30) stand so I couldn't resist.... I should be picking it up tomorrow and in the meantime I'm just trying to refresh my understanding of all this.