Thermostat overides central heating programmer

30 Nov 2010
Reaction score
United Kingdom

I don't if anyone can help with this one.

I have just replaced a very old beige Honeywell Mechanical themostat with a shinny new Honeywell T6360B.

The problem is that when the programmer (potterton EP2002) is off the heating will still come on this seems to be the thermostat telling it to aswhen you reduce the temperature it the boiler goes off.
When the last thermostat was installed the programmer did its job.

The bit I am not sure about is have I wired the new thermostat up correctly.

I have three wires Blue Red and Yellow.

I assume red is Live, Blue Neutral and Yellow switch Neutral (I think)

the thermostate is wired 1 = red 2 = Blue and 3= Yellow.

I have tested voltage and there seems to be 230v on 1 and 2 when thermostate is low. Also there is 230v on on 1 and 2 even when CH is switched off at Timer is this correct?

Is this correct as the installation instructions are rubbish.

The boiler I have is a Worcester Greenstar 18ri ( condensing not Combi). Fitted with Honeywell 3 way valve.

Thanks in advanced for any help
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neutral in 2 when it's fitted with an anticipator
live from programmer heating on in 1
sw/live to valve in 3
Thanks for advice

I have just been checking voltages and I am not still unsure.

i took red cable out but heating does not work now.

Blue in 2 and yellow in 3.

The 230v is coming off the red all the time even when progammer is switched off.I would have thought there would be no power there when programmer is off?

Are my wires coloured correctly I would have thought so.

check the colour of the wire on the heating call at the programmer.
it should be dead when programmer off.

thats the way i would of used the colours.
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Hi It looks like I have wired it the same as your picture.

I have attached picture of Thermostat and programmer.

I am not sure what the wiring is ment to be on programmer as it seems to be hard to installation guide for potterton stuff.

It seems the programmer left to right is

1 = Blue
2 = Empty
3 = Red with blue clip
4 = Yellow
5= Red which is looped in to the Live


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