Discharge from Boiler Cupboard Ventilation Grate

[nickldntw]

I wonder if anyone can help me with what may be condensation problem in the boiler cupboard.

My mum lives in a 1950's built ground floor flat and has a Worcester-Bosch Combi boiler situated in a cupboard in the kitchen. The boiler is regularly serviced and seems to work properly, it is fixed to an outside wall and has an external flu which works properly.

Unfortunately over the past year there seems to be an increasing condensation problem in the boiler cupboard. Quite a lot of mildew and damp has appeared. There is an external vent to prevent this sort of thing, but it doesn't seem to be particularly effective right now.

In fact there seems to be some kind of brown discharge coming out of the vent and staining the outside wall. The external vent is situated in a little alcove by a balcony, so it looks like it's in a corner. There is also some sort of pipe running to the flat above adjacent to the vent. This pipe also seems to be prone to condensation. I've attached a photo of the external wall.

What could be causing this? Nothing has changed in the flat, is it possible it's a slow leak from the upstairs flat that goes into the wall? Or could it be condensation from the section of ceiling above the vent? Or from the nearby pipe?

Any help would be greatly appreciated.

 

[Daveydub]

First, has she got a Co detector?
Quite possibly a leak from above but gas boiler surrounded by condensation is a bit disturbing.
On the flue outlet above boiler has the little plastic cap been replaced after the last service or is it open?

 

[nickldntw]

Yes, she has a carbon monoxide alarm and the boiler has just been serviced. Apparently it is working well and there's no problem with the flu. I will have a look tomorrow at the flu to see if there is a cap on it.

I'm worried about the condensation too, it should be dry around a boiler!

 

[Daveydub]

Yes, she has a carbon monoxide alarm

Tested & in date?

 

[nickldntw]

Yes, it's quite new, the first one she had fitted expired, after 5 years I think, so it was replaced.

If the boiler is faulty/unsafe would a gas safe engineer servicing the boiler be able to tell?

 

[Daveydub]

It sounds less likely that it is your boiler as it has been checked during the period that this has been happening so that is good. Have you had a look outside, water running down wall from guttering, downpipe, overflow etc. then try to get a look in cupboard in flat above.

 

[nickldntw]

Looks like the boiler flu is open, it has a metal grate over it to keep engineers out!

It seems the leak is coming from above.

Any idea what it could be?

 

[Daveydub]

I can't make out that first photo. Doesn't look right but then I am not sure what it is

 

[nickldntw]

It isn't a very good photo, as it does not provide a view of the whole flu. I've uploaded another photo that shows the whole thing.

 

[Daveydub]

That looks as it should.
No signs of water running down outside then?
Is the air vent still open to the outside?
It is possible that a small leak on the boiler, running down hot pipe is evaporating & then condensing on the cold spots so you could dry up everything, leave door open & heating off and look for any wet that appears.
I think that I would still want to have a look in the cupboard above though