replace room thermostat?Problem?

[mkflow]

hi needs some advice it anyone would be so kind.
I currently have a Room thermostat honeywell t6360B, the set up i have is an S plan. I have been given a honey well DT90E room stat and wonder if it would work if i replace it with existing. I have removed the t6360b room stat and have as followed - red (live/C) to 1
-blue (n) to 2
-yellow (s/l) to 3
-earth to eath.
the DT 90E room stat only has two wires? this is where i as stuck??

 

[Puddle]

You just use red and yellow wires,you do not need earth as double insulated or the blue neutral,try to disconnect neutral from source if possible

imho

 

[mkflow]

hi thanks for that puddle. wired as you suggested but now boiler wont fire when go to click room stat up??

 

[WHPES]

You could try Honeywell tech support