We have a gas boiler mounted on the wall in the utility room. It's an external wall and the flue is routed out of the top of the boiler and then directly through the wall it's mounted on.
Thing is, we live in a really exposed spot, and if the wind is strong enough and the rain is heavy enough and it's all coming from the right (/wrong) direction, like it is today, then rain gets blown down the flue and drips out of the bottom of the boiler.
After a previous episode I fitted a cowl like this (not my flue, but pretty much the same):
...but today is proving that it's not effective, cos the wind and rain are howling and water is dripping out of the boiler.
So, ideas?
Some sort of zigzag bend, similar to this, but much shorter and routed downwards?
We were advised to put this in 10 years ago because the main outlet was quite close to neighbour's property, so it redirects the exhaust gases into our garden, not his. I was concerned that the gases would burn a hole through the pipework, but was unfounded - it's been no problem in that time.
Yeah, that's kinda what I'm thinking. Thing is though, the flue is like a 'pipe within a pipe', the centre pipe that the gases come out of being the 'sticky-out' bit and the outer pipe, which I presume is for insulation, terminates flush with the wall. I'm pretty sure that the rain is coming into the outer bit, and extension pieces like yours seem to attach to the inner/sticky-out bit only.
It is a balanced flue. Inner pipe is flue gases out, outer pipe is air for combustion. Do not do anything to that.
No easy solution apart from re-routing or vertical balanced flue.
Ah, okay. Could the existing flue be converted into a vertical flue (so it comes through the wall where it currently is and then goes vertical)?
Is it a condenser boiler? Usually theyre designed so that any rain that gets blown in drains out through the condensate pipe. It may be the problem isn't the flue - in that in isn't incorrect that the rain is getting in that way - but a leak in the system that should be letting that water drain away properly.
Could you put another, similar cowl on the side? It looks from the pic as if its not cutout to be perpendicular to the wall, so there'd be a narrow v-shaped gap between them, but still better than one on its own
Water in the combustion chamber is normal for a condensing boiler. Is the condensate pipe blocked?
The rain is going through the outer pipe, that is not connected to the combustion chamber but is open into the case. It is then drawn through the combustion chamber, but if water is dripping from the bottom then it suggests it is going into the outer pipe. It is a flue do not adapt it unless you are suitably qualified
The rain is going through the outer pipe, that is not connected to the combustion chamber but is open into the case. It is then drawn through the combustion chamber, but if water is dripping from the bottom then it suggests it is going into the outer pipe.
That's exactly what's happening
It is a flue do not adapt it unless you are suitably qualified
Oh, absolutely. To rephrase my previous question - Could someone who's suitably qualified convert the existing flue into a vertical flue (so it comes through the wall where it currently is and then goes vertical)?
Bear knows their stuff 👍 download the boiler installation manual to see if it gives you any clues on what you "might" be able to do with the balanced flue & thereafter employ a suitably qualified engineer to do what is necessary, there are vertical balanced flues which have rain cowls but they may not be certified for your boiler.
download the boiler installation manual
No need, I have it in the stuff the previous owners left us, I'll have a read.
You can get 90deg flue elbows, so maybe you need something like that:
90 Degree Flue Elbow | Morco Products
with something like this stuck on the top
Ideal 203132 V3 Flue Roof Kit | Travis Perkins
Obviously on the advice of someone who knows what they are doing. IANAE 😁
Thread revival time. I've checked the installation manual and the boiler can have a vertical flue, so that may be an option.
However, I've had an idea...
I have the original cowl (the on I took off to replace with the 'rain stopping' one from the picture above). It's one of these boggo ones:
So, my idea is to get some stainless steel mesh sheets and wrap them over the top half of that cowl to form a sort of 'cap' and place some on the flat end, which is the end that faces the weather, as the rain can essentially be horizontal. The mesh has c.1mm 'gaps', so I'm thinking this is enough to stop (at least most of) the rain blowing through it, but is not too small as to impede the boiler exhaust gases (plus it'll be a distance away from the end of the flu anyway).
Is this a good idea, or a stupid idea?
Is this a good idea, or a stupid idea?
I'm afraid that any kind of home-brew modification that might affect the inlet/outlet pressures and flows of the boiler is a bad idea. Get a Gas Safe boiler engineer to specify and install whatever is designed to work with your boiler.
I still remember a piece of advice I was given by an old engineer about 35 years ago when I started my first engineering role. You've only got to know enough to know you know **** all. It's basically engineering rule one, and definitely applies to this scenario.
The problem isn't water getting in. The flue is installed exactly as it is supposed to be - even to the extent that the flue slopes towards the boiler so that water will run in the direction its intended to If you're getting water dripping from the boiler doing anything to the flue is the wrong approach. Putting a vertical flue on... hate to break it to you but rain also falls from above. If it would have been beneficial or necessary then it would have been installed with one to begin with.
Ask someone qualified to look at the boiler because 'water is dripping from the boiler' and they'll fix that problem for you. Don't bother them with your own theories unless you want to encourage them to also charge you for some additional unnecessary work.
We were advised to put this in 10 years ago because the main outlet was quite close to neighbour's property, so it redirects the exhaust gases into our garden, not his.
Once a month do you open the gate and let all the gases out? 🙂
The problem isn't water getting in.
It absolutely, definitely, is. I have taken the front of the boiler and seen it with my own eyes, dripping from the flue at the top of the casing. It then runs/drips down the various bits and bobs inside the casing, pools on the bottom of the casing, then drips out of whatever hole it finds there.
Putting a vertical flue on... hate to break it to you but rain also falls from above.
Yup, and the vertical flues have baffles to stop it getting in
The rain is going through the outer pipe, that is not connected to the combustion chamber but is open into the case. It is then drawn through the combustion chamber, but if water is dripping from the bottom then it suggests it is going into the outer pipe.
As I said above, this is what is happening
I'm afraid that any kind of home-brew modification that might affect the inlet/outlet pressures and flows of the boiler is a bad idea. Get a Gas Safe boiler engineer to specify and install whatever is designed to work with your boiler.
Yeah, fair enough, I knew that would be the answer
Putting a vertical flue on... hate to break it to you but rain also falls from above.
We have a vertical flue on our boiler. Boiler is in the airing cupboard upstairs & the flue pokes out of the roof.
It has a cap on it, similar to the one I posted in my reply above (like a toadstool shaped thing) & we have no issues with water pouring out of our boiler.
Vertical flues don’t have issues with rain as they pull air from below for that very reason.
whether you can fit one to yours is a matter for a suitably qualified engineer and a site visit