ideal boiler C24 water overflows from external pipe

Hello

I have got C24 ideal mini central heating boiler, this is fairly new one 2 - 3 years old. From few days it has started overflowing water through external pipe. This happens only when heating is on. when heating gets on a lump of water comes out through this pipe and then it drips continuously until heating remains on.
Also i have noted that bar pressure remains at 2.5 when heating isn't off and goes up to 3.5 when heating is on.

I tried bleeding the radiators and pressure came down to 1 bar but again in few hours its gone back to 2.5.

Could anybody suggest me what should I do.
Any help on this is much appreciated.

Thanks

Leaking filling loop!

Probably a failed expansion vessel as well.

If you want to try to fix it yourself try reading the FAQ section of this site.

Tony

Thanks Tony

Filling loop pipe is not attached,

is it possible to guide me how to fix this myself.
you talked about FAQ - is there specific topic on this, could you give me a exact link to that please.

Regards,

If filling loop not attached then the plate heat exchanger is presumed to be leaking internally. Thats very rare on your model but can happen to 1 in 10,000 boilers! There were more likely on boilers made 2002/2003.

That becomes a rather more involved job as it will have to be replaced.

In addition the expansion vessel is faulty/discharged but you could deal with that yourself.

Tony