Boiler won't switch off

[timbo3]

Hi all, I wonder if anyone can help me solve this problem. I was sitting at home watching TV when the earth trip went, I managed to isolate the problem to the CH system. Although I didn't manage to identify the actual culprit after a while of trying to discover the problem the trip switch stayed in. Problem now is the boiler works normally but when the controller turns everything of the boiler continues to operate without the pump.The boiler can be turned off at the boiler. The boiler is an old trianco redfire, the controller is a drayton 522, there is a frost stat and a boiler stat, which I have replaced (read some where this could be the problem and it was cheap to replace), the 3 port valve seems to cycle normally and defaults to hot water.

 

[Tipper]

Could be the aux contacts in the valve that have failed which fires the boiler 24/7.

I would change the valve motor head.

 

[timbo3]

Thanks for the reply Tipper, do you mean in the 2 port valve? its about 14 years old. Unfortunately the installer ran one of the pipes back on itself and over the top of the valve so getting this off is going to be a major problem. Is there any way of testing to see if this is the problem?

 

[timbo3]

Update, just noticed a solitary drip of water from the valve, could this indicate the problem, and maybe the reason for the earth trip incident?

 

[bengasman]

As you probably have figured out for yourself, testing electricity in the vicinity of water and copper pipes should only be done by people who know exactly what they are doing.
If looking at the schematics does not tell you all you need to know, I suggest you don't do it yourself.

 

[timbo3]

Yeh I know, I'm being careful, I have some experience of circuits etc, I teach physics to secondary pupils.
Update, the pump does not cycle at all now and the trip has blown again, looks lie everything is pointing to the 2 port valve.

 

[bengasman]

Yeh I know, I'm being careful...

Careful is good, but are you also competent working on live 230V?

 

[timbo3]

Yes when its switched off!

Can anybody tell me if my ACL lifestyle valve 679H 340-30L0 22mm is replaced by ZA 5/679-3 22mm valve, seen one on E-bay.

Mine has 6 wires but only 5 are connected, the one not connected is a very thin white wire.