Water leak from boiler after torrential rain

grumpy_codger

This hole has something to do with the internal condensate trap. Overflow? Needs cleaning? - How to clean, remove / refit condensate trap Ideal Logic boiler step by step - YouTube

WIAWSNB

Hi GQ.

Not to be complacent, but the really water-sensitive component is the PCB which can be damaged by a water leak, but that is contained within the fold down front where it's hopefully protected and away from this water. All the other leccy connectors - to fan, spark, pump, diverter, etc are usually in safe locations where only sprayed water would get to them. That probably explains how relaxed the GSs were about you continuing to use the boiler if it's still working. Any water landing on a 'mains' voltage connection would be expected to trip your RCD. But, your call. The alternative is to pay the ~£100 for GS confirmation.

I'm not going to suggest removing the front cover for a looksee as I don't know your level of competence. So, either fire up the boiler, or call out a GS.

I had a similar leak issue on a GlowWorm during building work when a gutter end was left off, and the resulting cascade landed right on the flue end. As others have pointed out, the flue slopes gently back to the boiler, so any water landing in either the inlet (outer ring) or exhaust (inner tube) would end up inside the boiler. Water going down the central exhaust pipe would/should end up in the condensate drain, tho' it's possible the trap could be overwhelmed and leak. The air inlet, however - outer sleeve - ends up supplying the fan, and I don't 'think' is completely airtight, possibly intentionally so it draws from the 'sealed' chamber surrounding the 'engine' so creating a slightly depressurised zone. With mine, water did leak out - I'm guessing from the outer air supply side - and dribbled out the bottom of the boiler.

If rain flowing down the wall got in under the rubber collar - between it and the wall - and trickled in on the underside of the flue - unlikely - I'd expect that to end up on the outside of the boiler, running down the casing, so I don't think it's that.

This issue should only happen under exceptional conditions. I wonder if, perhaps, your gutter overflowed towards its end, and wind blew this overflow over the flue end? Seems quite a stretch, but you never know.

Hmm, looking again at your flue end pic - tho' it's not clear - could it be that the flue isn't extending out as far as ideal? It almost looks as tho' the rubber collar is as far out as the outer sleeve of the flue? If so, then rain coming down the wall and over that collar may be drawn right in - literally sucked by the boiler. But, not clear.

When's your next service due? Perhaps you could bring it forward - two birdies?

twopenny

That flue is too short for an exposed big wall.

The wires resting on it will allow water to funnel behind onto the seal and any heat of the flue won't do them any good.

I'd look into getting a better, more up to date flue first. And get a boiler service to see if they find anything defective. It's the time of year for it and potentially cheaper than having a firm fault finding.

Two simple jobs together and you should find a local gas safe engineer will come.

grumpy_codger

https://forums.moneysavingexpert.com/discussion/comment/82123056#Comment_82123056

The wires resting on it will allow water to funnel behind onto the seal and any heat of the flue won't do them any good.

There's hardly any heat on the outside surface of the flue.

I'd look into getting a better, more up to date flue first.

The boiler is just 4 y.o., installed supposedly by a qualified person.

My money is on rain water getting into the inner (exhaust) pipe and then into a partly blocked condensate trap that needs cleaning to prevent overflowing. In this case a longer chimney won't change anything.

Boohoo

I thought the picture with the yellow box on it is a pressure relief valve.

I don't think this is allowed but would an inspection camera/endoscope be able to go inside the outer exhaust flue and see is any water has got into it though the outside of the flue of is it leaking from the round seal.

All this is assuming it is allowed and that the boiler is switched off .

WIAWSNB

The 'yellow box' item does look like the safety discharge pipe, and presumably it is bent back on itself to fire at the wall. The brick looks strange, as tho' removed at some point, but who knows.

GQ, any chance of a clear pic of the flue end that can be zoomed in to?

General_query

Hello all, thanks for the continued posts. We have a Gas Safe engineer (local big company) coming to have a look at 1pm today.

I have moved the wires off the top - just in case - but scarily noticed that although the flue is flush to the wall on the left hand side, it isn't on the right hand side at the top. Not sure if you can tell on the below photos but it isn't flush to the wall, so guess that's not helping with water coming in. I know it depends on the workman but do you think someone pressing it back flush against the wall and putting some kind of sealant on it and pressing it until it "grips" would help? Or do you think they want to come back and charge another £75+ VAT hourly labour then parts (sealant etc) on another trip? What if it needs a whole new flue fitting? 😯

Oh, and yes, that loose brick is what the installers did at the time (we weren't present) but it looks like they removed the pointing / mortar then removed the whole brick, stuck that pipe out the wall and then put it back without refilling the pointing, and looks like they had to chip away at the brick below. Separate issue to the leaking but still shows level of competence when installing it.

Will report back later, cheers.

WIAWSNB

Ok, not as I thought, alas.

The outer air-inlet part does protrude a reasonable amount beyond the sealing collar, so I presume it conforms, and certainly doesn't suggest that water could run down the wall, over the collar, and go straight in to that inlet.

As for the collar not sealing tight against the wall, I think that there is an inner sleeve to it too which goes part-way in to the wall, but - regardless - any water getting behind there would - if anything - run down the outside/underside of the flue, and end up outside the boiler casing, and not inside.

The GS should hopefully be able to trace where the water originated from - it tends to leave a trail inside.

Boohoo

The cable that had been on top of the flue sleeve could of over the months weighed down on it and slightly dislodged the seal.

Just an idea .

General_query

Okay, gas engineer has just come and diagnosis was totally blocked condensate drain, full of gunk and water. I showed him the flue outside with the gap in the "cover" at the top and he went up his ladder and showed me that it's actually a flexible plastic circular cover (I though it was a hard plastic non bendy type!) that just sits over the pipe, but it's not even sealed in place. He said even if water did get in it any gap it wouldn't enter the boiler from running down the wall into the gap. He said if it happens again you can buy flue rainwater covers to fasten above but they must be 75mm above the flue due to regulations. He said they can fit one but wouldn't bother as I can do it myself a lot cheaper, very honest of him. Example below:

https://www.amazon.co.uk/Bolier-Flue-Rain-Cover-Cowl/dp/B0BFBQ4TWW/ref%3Dasc_df_B0BFBQ4TWW?mcid=1437c60e6209308d87a47a4636e997f0&tag=googshopuk-21&linkCode=df0&hvadid=697257633820&hvpos=&hvnetw=g&hvrand=3484101238234366226&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9046662&hvtargid=pla-1817020341814&psc=1&hvocijid=3484101238234366226-B0BFBQ4TWW-&hvexpln=0&gad_source=1

He took the cover off, showed me the blocked condensate trap bottle, then shook and emptied all the gunk out of. Annoyed as I didn't see if he filled it with clean water before he put it back (as some YouTube videos show). Inside and bottom of boiler casing was also dry. Did some flue gas tests and levels were clear, then put cover back on. Total cost £90 inc. VAT.

Asked about a future service and he said he wouldn't bother as he had just done the checks they would do anyway in a service, again very honest of him. I will book one in next September though for own peace of mind.

So touchwood, all is good and sorted.

Thanks for your support / advice!