Boiler constantly on although programmer is off...

[Adam Dallmann]

Hi,

I`d really appreaciate any help regarding this new problem.
We have a house with a sealed central heating system and a water tank in the A/C.

Turned the heating on today for an hour, worked well, then noticed that well after the hour was up and the programmer switched off, the boiler (Ideal ICOS HE15) was still running, with a call for heat.
Turning the room stat made no difference and there was no clicking.

Turned the boiler off at the mains and the radiators slowly cooled, but there was a constant noise from the A/C, as if a pump was constantly running.
If I trip the mains switch, the nosie is gone, but comes back as soon as I turn it back on.

The moment I turn the boiler back on, with the programmer being off, it still signals a call for heat and starts to heat the radiators.

Is there any way to work out what could be faulty e.g.: PCB or motorised valve...?
Many thanks,

Adam

 

[rpm]

Are you saying the Icos is in the airing cupboard or a separate pump on it`s own is there?

 

[Adam Dallmann]

The Icos is down in the kitchen, and a primaflow circulation pump is in the a/c.

 

[Chuck]

Fairly good chance the motorised zone valve for the radiators has got stuck in the 'open' position. In most systems the call for heat comes from microswitches in these. They typically have a small lever sticking out of the case that you can see moving and/or move manually.

It's either the zone valve itself (mechanical issue) or the programmer/thermostat that tells it to open.

The wiring for the system is probably not quite right. Isolating the boiler should make in all parts of the system (pumps, valves, programmers) dead. Plenty of installers cut corners with this, however.

 

[Adam Dallmann]

Thanks, I tried turning it back on and moving the lever to the far side, but it's still heating the radiators. Does that make the motorised valve the likely culprit?

The other thing I noticed is that once the boiler is off, this lever has some resistance and returns to one side via a spring, however when I turn the boiler back on, it becomes floppy and easy to move around... Is that the normal behaviour?

 

[king of pipes]

That is how it should be bud the valve head in the picture is in the locked open manual position did you do that ? Flick it off that and try it again , more than likely its something to do with the valve . cheers kop

 

[Adam Dallmann]

I tried that position and way over the other side as well, but it still seems to warm the radiators either way...:S
Guess I'll need to call someone to have a look at it, no quick fix there... Cheers for all the help!

 

[king of pipes]

It should find it's own position you can only manually lock it open and the heating will work all the time the boilers on . Cheers kop