Honeywell DT90E - Installation Help

[denv]

Hi,

I have just installed an Honeywell DT90E room thermostat to a Worcester Combi 30si but the boiler is not firing up when I'm increasing the room temperate on the thermostat.

I've wired the Honeywell DT90E room thermostat with the following:-

A on the stat to LR on the boiler
B on the stat to LS on the boiler

Can anyone help as to why the boiler is not firing up on request?

Thanks

 

[stem]

My wiring diagrams show that

Thermostat A should connect to Ls (Live supply)
Thermostat B should connect to Lr (Live return)

Unless I have the wrong diagrams, there isn't an LN terminal

 

[45yearsagasman]

The connections should replace the original link between Ls and Lr

 

[stem]

OK thanks for revising your original post to correct the typo. (LN to LR) Your wiring is correct.

Sorry here if I'm teaching grandma to suck eggs, but is the setting you have turned it up to above the actual temperature of the room it is located in?

Also, has anything else happened, for example did you make a wrong connection earlier that may have caused some damage elsewhere?

 

[denv]

I checked the wiring and you're right stem, however the boiler is still not firing up.

Any idea why?

 

[stem]

OK thanks for revising your original post to correct the typo. (LN to LR) Your wiring is correct.

Sorry here if I'm teaching grandma to suck eggs, but is the setting you have turned it up to above the actual temperature of the room it is located in?

Also, has anything else happened, for example did you make a wrong connection earlier that may have caused some damage elsewhere?

How about that then! I answered the question before you asked it! Hope it helps, I haven't got any other ideas, except maybe a faulty thermostat. If you put a wire link between Ls & Lr the boiler should fire then. If it does the thermostat is probably faulty.

 

[45yearsagasman]

Replace the link between Ls Lr. Does the boiler fire then? I'm too slow at typing!!!!! I'm out. Leave it to you guys.

 

[stem]

It makes a change for me I'm normally the one in last place at least we speak in agreement

 

[denv]

Replace the link between Ls Lr. Does the boiler fire then? I'm too slow at typing!!!!! I'm out. Leave it to you guys.

I took out the new wiring and replaced it with the link, in lr/ls boiler working fine.so is the new stat faulty

 

[stem]

Looks like it, all the thermostat is, is a switch that connects the two boiler terminals, just as the wire link does.

I'm assuming that your connections to the thermostat were secure and the screws were on the conductors not the insulation.

Are the batteries in the thermostat fresh? i.e. not taken from a radio or something.