Replacing Honeywell Thermostat - Help!

[Chud]

Hi there

I'm in the process of replacing an old Honeywell thermostat with a new fangled digital type one...

In the old Thermostat the wires were connected as below:

Red (L) - terminal 1
Black (?) - Terminal 3
Blue (?) - Terminal 2

The new stat which is one of these http://www.screwfix.com/prods/40819...ting-Controls/Honeywell-DT200-Room-Thermostat
has 3 terminals labelled A, B and C

I'm not sure which wires go where as the instructions with the new stat are pretty dire

 

[Chud]

OK had another look at the back of the new stat and the terminals are labelled to correspond with the following:

A = COM
B = NO
C = NC

 

[D_Hailsham]

I'm in the process of replacing an old Honeywell thermostat with a new fangled digital type one

What is the model no of the old stat?

 

[Chud]

I think it is 42003878...

 

[D_Hailsham]

I think it is 42003878...

Don't recognise that number Any other clues? Honeywell stats were often T numbers, e.g T6360

 

[Chud]

try this
T6160B1004
8743

 

[D_Hailsham]

try this
T6160B1004
8743

That's more like it

Here goes.

Red to Terminal A (power from the time switch)
Black to Terminal B (power to boiler etc)

The Blue, which is a Neutral, is not used and should be made safe - e.g cut the bare end off and wrap in insulating tape.

Job done

 

[simond]

The cables that were connected to 1 and 3 on the 6160 should go to A & B on the DT200 (polarity not important).

The remaining (in your case blue) wire is the neutral and this should be separately terminated in a loose connector strip or crimp. Do not use terminal C!

 

[Chud]

What would be the result of using terminal c

I've connected up as you describe but the controller (Drayton Lifestyle LP522) is now acting odd (LED's are very dimly on but no life in the display...)

 

[simond]

Short circuit. Blown fuse/Programmer.

 

[Chud]

To elaborate on the above I connected it up (before) as follows:

Red - Terminal A
Blue - Terminal B
Black - Terminal C

On restoring power the controller (not the stat) came to life briefly then the display went blank and has remained in that state since correcting the wiring...

 

[Chud]

Are there any internal fuses in the controller - I've checked the 3 amp fuse for it's mains supply and that is passing current to the controller...

 

[simond]

Try the fuse for the system first.

Really, if you have no idea, have you considered the potential consequences of your actions?

Had the fuse not blown, you could have ended up with live metalwork around the house if the colour coding was wrong. The number of people on this forum that have a go without any idea of what they are doing with mains electricity is frightening.

Mains electrics should not be altered on the basis that 'if by some fluke I connected the wires up right it will work'. It is not a lottery, there is only one correct way of doing it. Goodness knows how many latent DIY live wires are out there, awaiting someone to kill themselves.

Perhaps Part P was needed after all.

 

[simond]

You need a new programmer now!

 

[tim west]

DELETE