Connecting Honeywell T6R-HW to Worcester Bosch Greenstar CDi boiler

[Hugo FS]

Hi all

I am trying to connect a Honeywell T6R-HW smart thermostat to a Greenstar 29CDi boiler. Before I start, I want to be sure I understand what connections are required, and it isn't helped when the connection labels are different from the two makers' tech docs. Does anyone know exactly what links to what?

I attach diagrams from Honeywell for connecting the T6R to a generic combi boiler, and the wiring diagram from the Greenstar installation manual. Also, Worcester Bosch give this video advice on connecting a boiler to an external control. All of them seem slightly contradictory or confusing.

I get that the mains live and neutral need to jum from the boiler to the T6R, but the Worcester advice seems to be to use a live-out and live-return via the external control, while the Honeywell advice seems to be to use their links A and B to make the thermostat switch connection. Which way should it be? If the Worcester advice then where do the three links connect on the T6R. If the Honeywell advice, then what do A and B connect to on the boiler.

Also, the T6R-HW is supposedly able to control the hot water using links D,E,F but their document only shows this if connecting S-Plan or Y-Plan, not for combi boilers. Is there no way of programming hot water pre-heating like with some other controllers (including the DT20RF that is being replaced)?

Many thanks in advance for any contributions

 

[CountryFan]

Can I ask why you have or are getting the HW version if you have a combi? You can use LS, NS for L and N at the T6 and then take Heating on to LR.

 

[Hugo FS]

Of course. I got the HW version because it was the same price as the plain T6R, and I may be moving soon so thought it might come in handy in future.

Many thanks for the advice. Not entirely sure I understand what your "Heating" refers to on the T6R. Can you clarify?

 

[CountryFan]

Not entirely sure I understand what your "Heating" refers to on the T6R. Can you clarify?

Yep, apologies. I forgot Honeywell use A and B, so in your case it would be B to LR

 

[Hugo FS]

Makes a lot of sense. So something like this?

Many thanks

 

[CountryFan]

Makes a lot of sense. So something like this?

Many thanks

Yes you can do it that way should you wish.

 

[Hugo FS]

Many thanks CountryFan. Fitted it this afternoon and all's well.