Help sought with Ferolli F24. Please read!

[gareth1982]

Hi all. I have just signed up here looking for help with the following:

I have a ferolli f24. The hot water works fine, but when the heating is switched on, the boiler trips the the main consumer unit after between 4-5 minutes. During this 4-5 minutes, the heating is working fine, ie the boiler fires, thepump kicks in, the rads get hot etc, then it trips at the consumer unit downstairs. If you reset the CU immediately, it trips within 10-20 seconds again, and if you wait til the boiler cools down then reset it, you get 4-5 minutes of the heating working again before it trips again. I have fitted a new pump, so it's unlikely to be a faulty pump (which was why I changed it). Any ideas?

This problem started with a leaking expansion vessel which I changed, then the low level pressure sensor was faulty, so I put a new one of those on, then the pump wouldn't run when turning on the heating, so I replaced the pump, and now it's only working for 4-5 mins (although the hot water works fine all the time).

Any advice would be gratefully received.

Cheers

Gareth

 

[andytw]

Is it an individual MCB that trips or is it the earth leakage trip ?
Just wondering if it is not the boiler but something external, e.g pipe touching a cable. Bit of a longshot, I know.
Other thing that might be of interest could be the room stat.

andytw

 

[gareth1982]

Hi andy. Thank you for the reply; it is appreciated.
It's the individual trip switch for the sockets that trips out (the fused spur for the boiler is on the same main as all the sockets in the house). I can't see anything untoward with the boiler wiring/pcb, ie anything touching each other that shouldn't etc. I'm really at a loss as to what it could be. The fact that it works fine for 4-5 minutes from cold is the confusing bit; but try resetting it with the boiler hot (ie immediately) makes it trip within 10 seconds.

Cheers

Gareth

 

[andytw]

What fuse is in the switched spur ? I would make sure it is a 5A then test again. I would expect the MCB that is tripping is 30A.
If the MCB still trips rather than the fuse blowing in the spur then I would be looking outside the boiler.
Faulty MCB is unlikely but not out of the question.
Is there another MCB circuit that has sockets on it ? It sounds like there isn't.

andytw

 

[gareth1982]

Hi again Andy.

Yes it's a 5amp fuse in the spur to the boiler. That was the first thing I checked. All the sockets (including the fused spur to the boiler) in the house are on the same MCB (30amp, yes) that trips.

I suppose I could unplug other things such as the kettle, toaster etc and try the boiler again...if it doesn't trip it, then I guess it's not the boiler that's the problem? I must admit, electrics aren't my thing.

Cheers

Gareth

 

[andytw]

And there will be a fuse in the boiler itself. I do not know if that protects the whole of the boiler, others on here will know. But that is just another pointer to it not being the boiler at fault.

andytw

 

[gareth1982]

Yes, there is a 2amp fuse on the PCB. This is not blowing.

I will experiment with unplugging kettle etc and see what happens.

Cheers


Gareth

 

[andytw]

If your kettle is not on and heating water then it would not be drawing any current. No harm, though, in removing everything that is plugged into that circuit.

I think, personally, I would be looking to get the MCB swapped.

Do you have a room stat ? Is the MCB tripping once the room stat clicks off ?

andytw

 

[gareth1982]

We have a very old fashioned manual control on the wall that's not temp sensitive as far as I'm aware; it's just a wheel (numbered 0-30 degrees) that clicks on when you turn it past 15ish (and fires the boiler and on comes the heating), and stays on forever unless you turn it off (below 15ish). It was once left on for 3 days when we went away for the weekend! Whether this is set at 15 or 30, the boiler trips the socket MCB within 4-5 mins.

Cheers

Gareth

 

[miggy]

Pump wiring harness where it attaches to pump have a habit of burning out. Have had exactly the same fault numerous times. sometimes they blow straight away or can last a few minutes.

 

[miggy]

Pump does not operate on hot water function, hence hot water ok. Look at the harness. sometimes you can smell it.

 

[St0rmer66]

We have a very old fashioned manual control on the wall that's not temp sensitive as far as I'm aware; it's just a wheel (numbered 0-30 degrees) that clicks on when you turn it past 15ish (and fires the boiler and on comes the heating), and stays on forever unless you turn it off (below 15ish). It was once left on for 3 days when we went away for the weekend! Whether this is set at 15 or 30, the boiler trips the socket MCB within 4-5 mins.

Cheers

Gareth

It SHOULD be temperature sensitive. Either the area the stat is located in is constantly cold or it is faulty .