Central Heatintg will not turn off.

[RidleyRumpus]

Prior to last week my CH was working fine.

The CH pump died and was replaced by a plumber earlier this week.
However the central heating then would not turn off even when the controller was set to off, it worked fine prior to last week.

Suspecting the motarised valve microswitch this has now been replaced. However the CH still will not turn off.

Any ideas?

 

[Agile]

Better to diagnose the fault before blindly replacing things!

What does the plumber have to say?

Tony

 

[RidleyRumpus]

I have not managed to talk to him yet.

Any idea to what could be the problem?

 

[Agile]

Usually a jammed motor valve but if the full valve has been changed that should not be faulty.

It might have been wrongly wired though!

Tony

 

[RidleyRumpus]

The wires were connected back up by adding an inline connector, which was much easier than going to the junction box. The wires were connected colour to colour to the original wiring ie blue to blue etc.

The original wiring was working last week ie prior to the CH pump replacement. The central heating pump just used the original wiring as well.

 

[RidleyRumpus]

Actually I think I might be a bit mistaken here.

I have now found that can turn the CH off if I turn down the thermostat. What I cannot do is control when it goes on and off from the programmer.

So no matter what position the programmer is in as long as the living room is below the temp set on the thermostat then the heating will be on. If I adjust the thermostat down below the room temp then the boiler/CH turns off. Am I right in thinking this rules out the valves etc?

Programmer knackered?

 

[RidleyRumpus]

Bump

 

[jackthom]

I'm suspecting a wiring error but if you have a multimeter you may be able to check whether the 'CH ON' going from the programmer to the room thermostat is permanently live, or maybe it's getting a permanent 230V feed from somewhere else.

You could eliminate the programmer by carefully ( mains voltages here so switch off first and make the wire safe) disconnecting the wire right at the programmer CH ON terminal, which should totally stop the central heating.