Can't turn off central heating

[whatmakesustick]

Okay I have a strange problem...if anyone can help that would be great!!

I have a Potterton6002 timer controller and a Potterton Profile boiler.

Here's how to produce the problem:
1) Put the HW on (either via timer or on constant)
2) Put the CH onto constant
3) Put CH to off

But, the CH stays on. The light on the thermostat stays on, and if i turn the thermostat right down, it stays on. The only way to turn the CH off is to turn the HW off. However, if I then turn the HW back on, the CH also comes back on even though it is in the off position!

The only way to the CH off is to...
1) Put the CH into the once position, ensuring that the CH does actually come on (i.e. the light on the controller and thermostat comes on)
2) Turn the thermostat right down, so the light on the thermostat goes off
3) Turn off the CH on the timer

I had no problems with the system until a few months ago. I thought there might be a problem with my timer so I replaces an ep2002 with an ep6002 but it has not made any difference.

I did replace the thermostat earlier in the year...

Any ideas would be much appreciated!! Thanks.

 

[jon26]

Thsi post is way complicated... !!

 

[Agile]

As you like replacing parts without knowing if they are faulty, why dont you try replacing your motorised valve(s) ?

Tony

 

[desmitch]

I have a similar problem but with a chaffoteaux "Calydra" combi.
the selector switch (on front of boiler) has been on domestic hot water only, all summer. yesterday the central heating operated, heating all the radiators.
At the same time the domestic hot water was cold.
The boiler was of course firing up.
This is the current position and I have switched off the boiler.
I have no intention of replacing any parts myself but would like to know what the problem is, though I beleive that it will be similar to the above.

any comments would be appreciated

 

[whatmakesustick]

As you like replacing parts without knowing if they are faulty, why dont you try replacing your motorised valve(s) ?

Tony

I am not sure if you are being sarcastic or not with your suggestion regards the motorised valve? Do you think this could be the problem?

I had to replace my ep2002 regardless of this problem anyway because one of the slider switches was faulty and did not always work.

 

[assured heating]

what is the boiler ? not a micron by any chance

 

[Agile]

I have a Potterton6002 timer controller and a Potterton Profile boiler.

To Desmitch, if you want help with your problem then you should start your own thread. A combi boiler operates in a completely different way to the conventional system being discussed here.

We can only suggest what might be causing the problem. Rather than just changing parts on spec, a competent boiler engineer would check a part before changing it. Of course not all do!

Tony

 

[desmitch]

Thanks Tony,
,though I have, in the past, installed a complete central heating sysem (checked out by a CORGI reg plumber) I have no intention of "fixing" this problem..my present interest is just accademic and it may be of interest to other board members. I will post on the correct section