worcester bosch nest help

[mattjfisher]

Hi all, i was wondering if someone could help me with a nest boiler issue.

I have a worcester bosch greenstar 88 Cdi classic combo boiler and a nest 3rd Gen. I have tried to wire it in using manual and also a forum i found here for advice but have come a cross some problems. I have managed to wire the nest heat link in, get power to it, connect to the thermostat no problem however when it calls for heat during test nothing happens.

Please see diagram I've used, plus a few pictures (i know wire colouring may not match how they are in the right place)







I took out the link between Lr Ls as instructed on the worcester bosch 3rd party video. https://www.youtube.com/watch?v=iJ3nPK9ZSJs

If anyone has any advice i would greatly appreciate it


Thanks

[jdwoodbury]

Did you replace a standalone programmer or is it integrated into the combi?

[mattjfisher]

On the boiler itself it has ‘off’ ‘timed’ ‘once’ and ‘on’ this is set to on.

We have a Worcester digistat thermostat that we control the boiler with, this is on a scheduled timer.

[BrabusMog]

Not the same receiver but we had a fking nightmare recently with our Worcester combi. Took me ages how to figure out how to fix it.

[mattjfisher]

BrabusMog said:

Not the same receiver but we had a fking nightmare recently with our Worcester combi. Took me ages how to figure out how to fix it.

Fix it to work with a nest?

[mickmcpaddy]

What happens if you put a link wire betweeen LS and LR and was this link there before you fitted the nest, with the link the boiler should fire. 2nd question, is the digistat Worcesters own wireless version?

I'm not 100% sure whether the digistat needs the above link in to work or whether it overrides those terminals, if it needs the link then the boiler will only work when both the next and the digistat call for heat or if it overrides them then the nest will never work until the digistat is disconnected completely.

If the digistat is what I think it is then the square panel on the front of the boiler needs removing and the ribbon cable needs disconnecting.

Although I'm slightly confused as you have a mechanical timer on the boiler and also a digistat, why both?


Edited to add : I forgot to say that the way you have stripped those cables back is dog rough and could easily kill someone

Edited by mickmcpaddy on Thursday 8th February 17:32

[mattjfisher]

Yes before i fitted the nest there was a metal link between LS & LR.

When i was troubleshooting i tried to get the boiler to work with the digistat however boiler did nothing, once i disconnected everything and put the link back in it worked fine again.

I'll try a link wire now and see if the nest works. In terms of the digistat couldn't i just take out the batteries? Yes it a w&b digstat (see pic) and front of boiler.


And yes i know about the wiring, was a quick job to see if it worked, once i know it works properly its getting tidied up.

\




Thanks Again

[mattjfisher]

Ok so have wired a loop between LS and LR. Nest won't work, i can't still use the digistat though. Have tried turning off the digistat but still no avail.

Anymore ideas?


Thanks

[mickmcpaddy]

Just unclip that front panel and remove it, it should then work the way you wired it before.

[mattjfisher]

mickmcpaddy said:

Just unclip that front panel and remove it, it should then work the way you wired it before.

Unclip it where?

[mickmcpaddy]

The front panel as in the panel on the front, the square thing that is the timer, it just unclips and pops out, it either has pins on it that plug directly into the PCB behind or there is a short ribbon cable that unplugs. Most boilers come with a blank panel that fits there and you take the blank out and fit a timer like you have, this then overrides the Ls/Lr terminals.

https://www.youtube.com/watch?v=jQ-VRVtV8e4