Ideal HE15 boiler advice

[PThomas]

Morning All

We have a Ideal HE15 boiler that's around 10 years old.

Recently I have noticed that the pump in the airing cupboard seems to be running continuously. Looking at the boiler it has 'c' on the display which means 'boiler is active for central heating'.
Currently the wall timer is set off for CH and on timer for HW.
I have tried switching the timer to off for both, yet the boiler still shows 'c' and the upstairs pump is running...

Any advice how to proceed? Possible boiler fault or maybe incorrect wiring or maybe failed valve?

Thanks in advance for suggestions and advice

 

[pallen5000]

It could be a faulty diverter/zone valve which will probably be in the airing cupboard.

 

[twgas]

I would be suspecting the HW valve end switch to be the problem, not opening when valve closes.

 

[PThomas]

Thanks guys

There are two valves in the airing cupboard, how to identify which is which?
Is it possible to swap the switch only or does it have to be the whole head or unit?

Both are inline with only one in and out, not three way.
One is Honeywell and one Drayton.

 

[45yearsagasman]

Its a bit of a faff to change microswitches, but not impossible. Most modern valves have removable heads and its far better to go down that route IMO.
The outlet of the HW valve will go directly to the cylinder, so its easy to ID.
No need to drain down and you can use a 5point in line connector if you don't feel comfortable in disturbing wires in the wiring centre.

 

[PThomas]

Ok, it seems to be the Honeywell 272848 unit that's faulty.
It seemed to be stuck open/on.
Upon removing the metal cover I moved the internal switch arm off the micro switch and everything went back off. This is the one that controls hot water, central heating continues to work normaly using the Danfoss unit.

If I now put HW timer to on and run the hot tap it doesn't seem to be activating....
Is this likely to be the valve or just the switch?

 

[twgas]

You would need to run off enough water to cool the cylinder 'stat. It's probably easier to just turn the cyl stat up. It may well work ok for a while but it wont be long before it sticks again.

 

[Alex10]

Personally I would just disconnect the grey wire from the wiring centre
If it goes off it's the one you disconnected. If not you know it's the grey wire that's left in powering the orange up.

 

[Boilerman2]

As you say the HW valve was stuck open, I suspect that you will need to replace the synchonous motor in the powerhead these can be obtained for around £10