room thermostat

[callasda]

Both red and yellow wires show live with a neon tester.
Shall I try connecting the blue and the yellow together ?

 

[EFLImpudence]

No.

You will damage something if it is a neutral.

Do you have a multimeter? If not, then go and get one.

 

[callasda]

Should I try and connect together the blue and the
yellow or the red and the blue ?

 

[callasda]

A multimeter on ebay costs around £40.00

 

[sparkwright]

No - same thing - you may damage something with that kind of guess work.

Photos may help. It may be helpful to find the other end of that roomstat cable.

Getting a multimeter would be the best place to start.

 

[sparkwright]

A multimeter on ebay costs around £40.00

You can buy a cheap one from a DIY shop for £5 - £15.

 

[EFLImpudence]

You cannot do electrical work without one - whatever the cost.

 

[callasda]

what will that tell you that a neon tester cannot ?

 

[EFLImpudence]

Reliable information.

You will see the difference when you get one.

 

[EFLImpudence]

Determine what the blue wire does with your neon.

 

[Notch7]

I stupidly threw away the old stat

Its a bit unlucky to have your bin collected between taking off the old stat and fitting the new!

I bet you wish you hadnt started now!

 

[sparkwright]

A neon tester is only good for guidance.

You can't rely on them, they give false readings and you have to confirm your findings with a multimeter.

A neon tester will not give you voltage readings, so you cannot be sure of what's going on.

 

[callasda]

Inexplicably the CH is has come on and the green led on the boiler is on as well
The red wire is connected directly to the yellow wire with no thermostat

 

[flameport]

Inexplicably the CH is has come on and the green led on the boiler is on as well

Is there a timer, programmer or other control?

 

[ericmark]

Inexplicably the CH is has come on and the green led on the boiler is on as well
The red wire is connected directly to the yellow wire with no thermostat

OK now you know the red and yellow wires control the central heating, I wonder if there is a timer or some thing else which had lead you astray?