Search the forum,

Discuss Gap in boiler tube help in the Central Heating Forum area at PlumbersForums.net

Messages
12
Hi, I just moved into a house about a month ago and today I noticed a small gap in the tube above the boiler flue. Is this something I need to call an engineer out asap? I guess so but wanted to post just in case people have explanation of this setup.

I poked a tiny tie wrap and it goes all the way into the pipe. It appears this bracket is covering a large gap between the two pipes, which to me doesn't seem correct?

I've had a CO alarm next to the boiler since I moved in, which has not reacted.

Any help much appreciated as this is very worrying.

(lots of the other jobs here seem botched too as it was rented previously and it seems no one cared, all the radiators leak and need replacing due to rust)
 

Attachments

  • gap.jpg
    gap.jpg
    220.8 KB · Views: 22
Last edited:
This is something that needs to be inspected and rectified by someone with Gas Safe Registration, there should be no gap there, with collar just covering where the two flue parts meet. I would advise the boiler is not used until it has been properly sorted, regardless of having a CO monitor.
 
This is something that needs to be inspected and rectified by someone with Gas Safe Registration, there should be no gap there, with collar just covering where the two flue parts meet. I would advise the boiler is not used until it has been properly sorted, regardless of having a CO monitor.
Thanks Nick. I have turned it into "standby" mode, which says it has frost protection and pump circulation features but with not provide hot water or heating" Or should I turn it off fully with I guess the fuse box?

Thanks!
 
I have found the "gas safe" document from 10 may 2022. I really don't want to hire the same person who installed it before I moved in. Is there any reproach the person who installed this or is the gas safe register just a gimmick?
 
I would isolate the boiler from the electric supply until it has been checked over. Either use a referral, ask friends, or go on the Gas Safe website to find a local engineer.
Probably worth asking them to check the whole installation over, usually poor work is not isolated to one part of the install.
If you take photos of what is found it could be passed to Gas Safe, but from experience they can't/won't do much.
 
I would isolate the boiler from the electric supply until it has been checked over. Either use a referral, ask friends, or go on the Gas Safe website to find a local engineer.
Probably worth asking them to check the whole installation over, usually poor work is not isolated to one part of the install.
If you take photos of what is found it could be passed to Gas Safe, but from experience they can't/won't do much.
Ok thanks Nick, yes I would request them check it all over. It's certainly a mess underneath where they put it into the wall too so they weren't too bothered overall. The outside attachment also looks a bit wonky but maybe thats ok.
 
Yes it’s classed as at risk (AR) if it’s just the air intake, but would get bumped up to immediately dangerous (ID) if there’s evidence of products of combustion (with CO). The CO alarm is too close to the boiler, should be a minimum of 1m to a maximum of 3m away from the appliance. You’ve done the right thing by turning it off as per @IND_Nick. There’s probably no recourse as the engineer would argue it was installed correctly at the time, unless, the other side isn’t screwed to the clamp bracket? Seems odd with what appears to be a random screw in the flue.
 
Yes it’s classed as at risk (AR) if it’s just the air intake, but would get bumped up to immediately dangerous (ID) if there’s evidence of products of combustion (with CO). The CO alarm is too close to the boiler, should be a minimum of 1m to a maximum of 3m away from the appliance. You’ve done the right thing by turning it off as per @IND_Nick. There’s probably no recourse as the engineer would argue it was installed correctly at the time, unless, the other side isn’t screwed to the clamp bracket? Seems odd with what appears to be a random screw in the flue.

Hi, I turned it fully off isolated it, it has this inner part though, so does the pipe need to align? Its an Alpha Evoke 28 Combi, so perhaps the outer part doesn't provide the seal.
 

Attachments

  • alpha-90-degree-flue-bend-6-2000.jpeg
    alpha-90-degree-flue-bend-6-2000.jpeg
    34.9 KB · Views: 14
  • Screenshot 2023-02-26 at 19.15.55.png
    Screenshot 2023-02-26 at 19.15.55.png
    466.2 KB · Views: 16
UPDATE* Having turned it all fully off, I slackened the bracket, which appears to be just cosmetic and doing nothing. Inside appears to be inner pipework. I don't know if all boilers are like this. I am going to call someone to come look at it tomorrow.

Incidentally the other side of the bracket has holes in it too, see photo for other side, it appears to be doing nothing much as the pipe on the wall and pipe on the boiler are rock solid. It's maybe a cosmetic thing, or if all boilers have inner tubing I guess it's just a bad installation, surely it should connect up.

Also see attached for another persons boiler, same type, it has the same bracket on with the two unused holes

Im sure no one is interested, but I found a boiler installation of this and apparently the holes are for self tapping screws, but according to the boiler maker not needed (?)
 

Attachments

  • IMG_0081.JPG
    IMG_0081.JPG
    139.8 KB · Views: 14
  • IMG_0082.JPG
    IMG_0082.JPG
    90 KB · Views: 13
  • Screenshot 2023-02-26 at 19.35.14.png
    Screenshot 2023-02-26 at 19.35.14.png
    2.6 MB · Views: 14
Last edited:
No, it’s definitely not cosmetic. The outer flue (the part you’re concerned with) is the air intake for the combustion process, and the inner plastic flue is what takes the products of combustion (POC) away. This is why I said it’s at risk, but should POC be evident, then immediately dangerous.
 
No, it’s definitely not cosmetic. The outer flue (the part you’re concerned with) is the air intake for the combustion process, and the inner plastic flue is what takes the products of combustion (POC) away. This is why I said it’s at risk, but should POC be evident, then immediately dangerous.

Thank you, sorry Im getting someone to come and fix it despite my amatuer takes on it. It's hard to believe someone who is registered gas safe thought having a gap like this was ok :( It's not like they would not have noticed the huge gap to then cover it with a bracket seems criminal.

Also I don't see how the engineer could state it was ever installed correctly as the flue is concreted in the wall and the two pipes are too short. It was only 6 months ago, he probably concreted it in the wall then realised it was too short and just decided to botch it. I don't know, but it's awful someone would do this knowingly.

(I have found online that the two blank screw holes are for self tapping screws, but not required by Alpha [boiler brand] It's only due to these screw holes I could see the hole into the pipe, if he had put the bracket slightly further back I'd never have noticed)
 
Last edited:
Are you sure the certificates, etc. are genuine and weren't faked up by the previous owner?

Anyway, as well as getting the gas installation checked, I suggest you get an electrician to do an electrical-installation condition report (EICR) as a matter of urgency. Dodgy landlords who cut corners don't usually limit themselves to just one area.
 
Are you sure the certificates, etc. are genuine and weren't faked up by the previous owner?

Anyway, as well as getting the gas installation checked, I suggest you get an electrician to do an electrical-installation condition report (EICR) as a matter of urgency. Dodgy landlords who cut corners don't usually limit themselves to just one area.
It's had an EICR a year before and it had some electric work done (minor smoke alarms and extractor fan) which I had an indemnity policy written up for as it was missing certificates. So they are at risk legally if any electrical issues. Overall the electrics are about the only thing that work ok, but yes I think probably is worth getting that checked too.

I get the impression the landlord owner did get things fixed, but on the cheap/didn't care too much as just renting it out. It's had a new kitchen fitted and that isn't great, but not as bad as it could have been. It's like every job has some kind of issue, even the on suite sink fitted upstairs i turned the tap on and all water came out of the cupboard below - they'd put a connection on skewed.

They obviously hid the fact all the radiators need replacing, my fault for not getting a survey this time (my first move failed and I had survey) But you'd think most people would replace the radiators when getting a new boiler if they had issues because..they installed all new carpets, yet all the radiators leak and they carpets are not the cheapest ones.

7 radiators to replace and they did replace one in the front room, BUT of course, they botched it. They've made a total mess of the wall either side plaster everywhere and they've used horrible looking hoses not pipes. To top it off it's coming off the wall because they didn't put it on properly, so that needs fixing too.

So far not enjoying home ownership.
 
Had it checked out and apparently it is safe to move the cover over the gap as its just air coming out of that part. Overall though not a great boiler, rather a cheap one.
 
Had it checked out and apparently it is safe to move the cover over the gap as its just air coming out of that part. Overall though not a great boiler, rather a cheap one.
Tbf and afaik, majority if not all boilers or intake/flue arrangements are of a similar setup, as in they have a clamp bracket over a joint, no seals as only air intake.
 
I wouldn’t even worry about it. Looks like the top is nearly touching and due to the angle of flue, the bottom has opened up a bit.

I’m not saying I’d install it like this but if we use a bit of common sense, it’s the air intake. It’s not an air tight seal to begin with, so a 5mm gap, makes very little difference.

It’s not under positive pressure, so any leak in the inner tube won’t get forced out of the air tube but rather sucked in to the boiler and reburnt.

If I found it, rather than break cement, dismantle/reinstall flue, I’d test and likely wrap it with silver tape, refit the clamp and screw the clamp.

I’d also be quite happy to stand up in court and explain my decision process.

Sometimes we as engineers need to use our common sense and on site judgement.

Now if I found something like this......it’s a different story....

159E5293-241D-48B4-8D94-D92EAD1F0149.jpeg
12379DB4-9933-4BAA-A819-1D692DF4854D.jpeg
91B6EE68-3F4C-40E8-B2DC-EAFF03214981.jpeg
 
Tbf and afaik, majority if not all boilers or intake/flue arrangements are of a similar setup, as in they have a clamp bracket over a joint, no seals as only air intake.

I wouldn’t even worry about it. Looks like the top is nearly touching and due to the angle of flue, the bottom has opened up a bit.

I’m not saying I’d install it like this but if we use a bit of common sense, it’s the air intake. It’s not an air tight seal to begin with, so a 5mm gap, makes very little difference.

It’s not under positive pressure, so any leak in the inner tube won’t get forced out of the air tube but rather sucked in to the boiler and reburnt.

If I found it, rather than break cement, dismantle/reinstall flue, I’d test and likely wrap it with silver tape, refit the clamp and screw the clamp.

I’d also be quite happy to stand up in court and explain my decision process.

Sometimes we as engineers need to use our common sense and on site judgement.

Now if I found something like this......it’s a different story....

View attachment 81776View attachment 81777View attachment 81778

That looks awful. I'm still not totally happy about it and overall I don't feel its safe, although a gas safe person installed it and a gas safe engineer moved the bracket for me, but he didn't apply any tape and he didn't put any of the self tapping screws in.

Im not sure if I should get someone else out to apply some tape and screw it in or if its not worth it. Even doing that it seems a terrible design to have two pipes the same diameter just meet and then put a cover over it. They could at least overlap, but if this is the design of the boiler and flue then it must be meant to be like this I guess and Ill just always be worried about it.

I also found a video on youtube installing it (slightly different boiler but looks like exact same flue) and he asked the official alpha rep about the holes in the cover and they said they were self tapping screw holes but it does not need the self tapping screws (so why have the holes then!?) Unfortunately in the video he does not show installing the flue part so I cannot see if he had a gap too.

I also turned it on the other day when the heating was on and the water came out at 80 degrees for a brief moment (stated on boiler, apparently not the real temp) and the boiler made a weird clank noise. So it really is not inspiring any confidence from me, even though its brand new (installed by previous owner to just sell house)

 
Last edited:
Sorry Im sure no one is interested, but the best photo I can find it appears this is the design flaw imo. I don't see how any engineer can fit it much better, two pipes with the same diameter to meet and that bracket covers the gap, which is inevitable to have a small gap.

(Although I cannot tell from the photo, maybe it does slide in and provide an overlap. One thing I don't have is the plastic covering finishing piece on the wall, that I guess is missing)

The further flaw is, having the "self tapping screw holes" (which according to Alpha tec don't need to be used) means if the bracket is installed slightly forward or back, these holes can let air out by mistake.
 

Attachments

  • hboi301-2-flue.jpeg
    hboi301-2-flue.jpeg
    67.7 KB · Views: 9
these holes can let air out by mistake.

That’s the thing, it is just an air pipe. It’s fresh air being drawn in.

Not all boilers are “room sealed” with concentric flues, as yours is.

They can be “open flued”, drawing their combustion air from the room, in through the case.

I’m theory, you could completely disconnect the white air pipe, keeping the internal combustion flue connected, and as long as the combustion flue is installed correctly and undamaged, there’s no risk.

It’s not a flaw, it’s a calculated, safety tested design decision.
 
That’s the thing, it is just an air pipe. It’s fresh air being drawn in.

Not all boilers are “room sealed” with concentric flues, as yours is.

They can be “open flued”, drawing their combustion air from the room, in through the case.

I’m theory, you could completely disconnect the white air pipe, keeping the internal combustion flue connected, and as long as the combustion flue is installed correctly and undamaged, there’s no risk.

It’s not a flaw, it’s a calculated, safety tested design decision.
To be fair, it's not just an air pipe. It's an integral part of a room sealed, balanced appliance that should be installed correctly. I appreciate what you are saying, and with experience you can make, correctly, decisions on safety. However, as a rule there should not be holes or gaps of any sort in this type of flue.
Open flue/naturally vented appliances are completely different and in my opinion should not be mixed up in this thread as completely different.
The original query was the gap/hole in the flue. If the collar had been installed correctly covering the joint equally, tightened etc, job done.
 
Thank you for your information guys. On the one hand it appears fine, a gas safe engineer originally installed it (previous owner) I've had another engineer say its ok and move the bracket (he also said it wasn't a fan of the boiler though) On the other hand it doesn't feel safe to me to have a gap in a pipe like this.

Here is a picture of the outside, you can see the white showing through and also that is the side where there is a gap on the interior, so I guess it's at a slight angle probably.

The boiler has good reviews online but I don't feel that safe with it, it seems to make a clank inside when the heating is on for a while and you turn on the hot water in the kitchen next to it, the temperate shoots up in temperature briefly and Ive twice now heard a clank noise inside.
 

Attachments

  • IMG_0129.JPG
    IMG_0129.JPG
    845.3 KB · Views: 4
  • IMG_0125.JPG
    IMG_0125.JPG
    947.4 KB · Views: 3
  • IMG_0126.JPG
    IMG_0126.JPG
    545 KB · Views: 3
  • IMG_0127.JPG
    IMG_0127.JPG
    888.8 KB · Views: 4
  • IMG_0128.JPG
    IMG_0128.JPG
    607.6 KB · Views: 4

Reply to Gap in boiler tube help in the Central Heating Forum area at PlumbersForums.net

Creating content since 2001. Untold Media.
Back
Top
AdBlock Detected

We get it, advertisements are annoying!

Sure, ad-blocking software does a great job at blocking ads, but it also blocks useful features of our website. For the best site experience please disable your AdBlocker.

I've Disabled AdBlock