• Welcome to PlumbersForums.net - The international free plumbing advice forum. Professional plumbers sharing advice with fellow plumbers and DIY alike. Register for free today! - Checkout the Plumbing Advice forum and then our Plumbing Videos area which still needs populating.

Discuss Replacing a Honeywell T40 thermostat with a Honeywell DT90e in the Central Heating Forum area at PlumbersForums.net

JackStraw123

Messages
2
Hi
I'm replacing my old dial thermostat with a digital
The wires going in from left to right are
Earth
Blue
2x Black
Brown

When electrically tested none are live with thermostat off

Research on this and other sites suggest
2x Black into B
Brown into A
Tie off and isolate Green/Yellow and Blue

You don't have permission to view attachments. Attachments are hidden.



Is this correct?
My hesitation is the fact that I have 2x Black and not one

Many thanks
 

Attachments

    You don't have permission to view attachments. Attachments are hidden.

ShaunCorbs

Staff member
S. Mod
Plumber
Gas Engineer
Messages
30,341
Solutions
1
Make safe neutral eg blue, make safe earth eg green and yellow

1 from old into a on new
3 from old into b on new
 

Reply to Replacing a Honeywell T40 thermostat with a Honeywell DT90e in the Central Heating Forum area at PlumbersForums.net

Similar threads

L
You need to find these wires in your wiring centres and then bell them out to confirm One end / core will be in where your 2 port valve brown...
Replies
2
Views
536
ShaunCorbs
ShaunCorbs
C
Leave it on constant and control it via a programmer room thermostat on the wall ? Eg wired combi pack 4 mains
Replies
2
Views
109
ShaunCorbs
ShaunCorbs
ecm200
Replies
1
Views
636
ecm200
ecm200
Z
Hi Guys, just wanted to get some advice on the wiring of the new MC6 thermostat? I have attached a picture of what I am replacing and the wiring...
Replies
0
Views
1K
Zanderman
Z
N
  • Locked
As above you shouldn’t of changed the boiler your self how do you know it’s safe best to get a gas safe engineer out to quote for a new boiler
Replies
3
Views
770
ShaunCorbs
ShaunCorbs

Newest Threads (Please Reply)

Search Forum

Top