Nest Thermostat E to Baxi Duotec Combi

[MarkD1990]

Hi all, I'm new to this so I will get to the point and try to be clear as possible.

I'm currently trying to install a Nest Thermostat E with Heat Link to a Baxi Combo Duotec 28. There is currently a Horstmann Hrt4-zw attached with the wiring below for the wireless receiver.



Now how do I know which of these wires connect to the Nest Heat Link which is below



Many Thanks for any help given

 

[stem]

The black and grey wires in terminals 2 & 4 go the the e-nest C and NO terminals.

The blue and brown wires (230V supply) aren't needed by the e-nest because it's battery operated. They should be safely isolated / insulated and tucked out of the way, as should the earth wire.

 

[MarkD1990]

Brilliant thank you, I will give it a try in abit and let you know the results.

 

[MarkD1990]

I have done what you suggested, but when I turn the fuse box back on the boiler doesn't turn on because the fuse has blown in the plug, but when I put the old thermostat back on, I change the fuse and it comes back on.

Any advise on this?

 

[stem]

Then you have done something wrong. Check that the unused wires are isolated separately and insulated properly so that they are not in contact with each other or anything else.

Only the black and grey wires should be connected to the receiver C and NO. Nothing else should be connected to the Heat link.

 

[MarkD1990]

Then you have done something wrong. Check that the unused wires are isolated separately and insulated properly so that they are not in contact with each other or anything else.

Only the black and grey wires should be connected to the receiver C and NO. Nothing else should be connected to the Heat link.

I think I know where I've gone wrong I'm I right in thinking that when I use the wire connector below that I'm not meant to be putting the blue and brown in the same one?

 

[stem]

Indeed! Connecting a Live and a Neutral wire together is never a good idea. BOOM!

They should be safely isolated / insulated and tucked out of the way, as should the earth wire.

Like I said "isolated". Keep them all separate.

 

[MarkD1990]

Indeed! Connecting a Live and a Neutral wire together is never a good idea. BOOM!

Like I said



Keep them all separate.

Hahaha whoops may explain a lot then. Can I use insulation tape on the other wire? Or would I be better getting another block for the 3rd wire?

 

[stem]

Better to put them in individual blocks really, isolation tape can fall off after time.

 

[MarkD1990]

Better to put them in individual blocks really, isolation tape can fall off after time.

Brilliant thanks for all your help I will keep you updated once I'm done

 

[gas112]

I think I know where I've gone wrong I'm I right in thinking that when I use the wire connector below that I'm not meant to be putting the blue and brown in the same one?

View attachment 178894

pmsl cant beat a bit of diy

 

[MarkD1990]

Brilliant this has worked although the boiler seems to be on with the flame lit up and the radiators warming up even tho the nest is set to off via the app and the thermostat.

Any ideas?

 

[stem]

It shouldn't be this difficult! There are only two wires to connect.

You should have something that looks like this.

With either the black wire in C and the grey wire in NO

or:

the black wire in NO and the grey wire in C. It doesn't matter which way around they go. The terminals are quite close, so make sure that the copper conductors of the grey and black wires aren't making contact with each other.

If this is how it's connected, then the problem will most likely be due to a set up, or communication error.....

.....except there is a chance that you may have damaged something when you connected the live and neutral wires together and blew the fuse.

If it is wired up as above, as a test, you could try taking the wire out of the 'C' terminal. Make sure that it isn't touching anything at all, and restore power. If everything's OK, with the boiler it shouldn't come on now.