Upgrading Honeywell DT90E to DT92E

[enforcer109]

I have a Worcester Bosch Greenstar-Heatslave 18-25 Combi and the room thermostat is the Honeywell DT90E.
Now I have purchased a DT92E, which I thought would be a direct replacement, however I'm not sure how the wiring should be.
Currently there are two wires coming into the back of the DT90E (brown going to A and blue going to B) seems straight forward.
However, the DT92E has two lots of connectors, each with three connections. They are N L L & A B C
It would appear that my neutral will go to N followed by the live into the L next to it.
If I am correct in my assumptions so far, what extra wiring do I need to complete ?
TIA

Untitled

• enforcer109
• 7 Nov 2013
• 1

 

[denso13]

The two wires you have are a live and switched live, no neutral. You need an additional live and neutral fitted as you don't have enough wires at present for a wireless stat.

 

[wbjimmy1]

I also want to replace my hall-mounted DT90E with a wireless room thermostat ( possibly a DT92E) which I can move between the kitchen and the lounge. In my case I have a three core wire running between the upstairs programmer ( a Drayton Lifestyle) and the room stat but the third wire ( attached to the neutral connector at the stat) appears to be superfluous. Does this make any difference?

 

[MNW67]

possibly a DT92E

DT92E has been replaced by Total Home Wireless Digital Thermostat. I think the new one is actually a bit cheaper.

Total Home TTHWFD Wireless Digital RF Thermostat

www.plumbarena.co.uk

 

[wbjimmy1]

Thanks MNW67 but do you know if the BDR91 receiver can use the existing 3 core wire connecting my DT90E? Would I need to adjust the wiring within the control box?

 

[RandomGrinch]

Thanks MNW67 but do you know if the BDR91 receiver can use the existing 3 core wire connecting my DT90E? Would I need to adjust the wiring within the control box?

It depends on what you want to achieve?
As the new stat will be wireless, the BDR91 could be mounted closer to the programmer, where it may be less obtrusive.
The existing stat and wiring could be decommissioned.
If you don't mind the BDR91 replacing the existing stat, then that should be fine.
Posting a couple of photos of the wiring behind the existing programmer and thermostat should confirm.

 

[CountryFan]

Thanks MNW67 but do you know if the BDR91 receiver can use the existing 3 core wire connecting my DT90E? Would I need to adjust the wiring within the control box?

This may not work, as your Drayton Lifestyle programmer sends a live toe existing, so for it to be permanent you’d need to leave the Drayton on constant. It also requires a permanent neutral.