Boiler positioning and flue questions

[lukens]

Hi, in our new fat the boiler is currently in the 3rd bedroom, and we'd like to change this.

There are two main options that I see for positioning the boiler.

The first is in a large store room at the end of the hallway, this room however has no external wall, so we would have to run the flue through to one. There are two options I see for this, the first is to run it horizontally along the ceiling of the 3rd bedroom, and then box it in. The second is slightly harder to describe. Basically, there is a peculiar cavity in the wall in the store room that I think runs up to the roof. It can kind of be pictured as a really small chimney. It doesn't seem to extend below our flat (on the second floor) and it looks as though it runs up past the attic flat above. Do you think it would be feasible/permissible to run the flue up through this cavity?

The final option would be to locate the boiler in the kitchen. The most ideal position here would be in a built in cupboard between the chimney breast and an internal wall - would I then be able to run the flue up the chimney breast? Alternatively, I could locate it on the wall the other side of the chimney, and run the flue out through the wall; however, the alcove is not as deep this side, and so the boiler would stand out further than the chimney breast.

What do you think my best option would be?

 

[tonybhoy]

Leave it where it is.

 

[gasacs]

with out a site visit or detailed plans plus boiler manufacturers instructions being available it is not feasable to advise safely so would agree with the above... Leave it where it is

 

[lukens]

I'm not sure leaving it where it is is really an option, as the boiler needs to be replaced anyway, and the current flue is positioned too close to a vertical drain pipe for the manufacturer instructions for any of the boilers I've looked at (Worcester-Bosch or Valiant condensing boilers). It's also unlikely I'd be able to use an external plume management system to get around this, as it is a listed building (and even if I could get consent, it wouldn't be a desirable solution).

So, it would, at least, need to have some internal flue to reposition the point where it exited the building, so my feeling was it may as well be moved to the store room and have the flue run along the length of the ceiling of the 3rd bedroom, as it would be to have the flue run up from the boiler.

The cavity or chimney options were simply because having it exit via the roof would be preferable to having it exit via the front wall, and the second kitchen option would be to avoid any complex flue system.


The other issue with leaving it where it is is that it further limits the available space in what is already a small room.

 

[tonybhoy]

75MM is all you have to be away from a drainpipe if the boiler is fan-flued in any event you can simply extend the flue terminal beyond the drain pipe so that the flue is out approx 6inch or so from the face of the building.

You can fit the boiler internally with a two pipe flue arrangement however the cost of additional flue components makes most jobs like like these prohibitive.

You really are best to have someone or three have a proper look at the proposals and advise accordingly.

 

[wiggikins]

Why not just divert the vertical drain pipe? Is this the soil stack or a rainwater pipe,is it cast iron or plastic?

 

[lukens]

It's a cast iron pipe; there's also nowhere to divert it to, other than the neighbour's wall (and even then, it would again be a listed building issue).


I've been convinced though, I think I'm mistaken about the positioning anyway, and it should be OK where it currently is (it was actually where I'd initially thought of repositioning it to that was the problem). It's a tight squeeze between a window and the drain pipe, but it's probably just within the requirements. Also, leaving the flue where it is means I don't have to worry about getting consent to reposition the flue, and can therefore get on with having the new boiler installed without waiting for consent to come through first.

Obviously, it's still not ideal having it in a bedroom, so maybe at a later date (when I have more time and money again) I can look again at moving it.

Thanks for helping me see sense!

 

[tonybhoy]

You need to be careful wrt to the window and the flue.

Is the window an openable one?

Usually 300mm from an openable window and re the WB 42CDi (for example) distance from a waste pipe is 150MM however you can get round this by doing as I suggested below however some manufacturers are pretty picky about doing this so you need to ask them.

 

[lukens]

It is an openable window, but I believe the required distance from an openable window is 300mm, and it will already be about that far from it once it is past the window surround (my understanding it that it needs to be 300mm from the actual opening in the building, rather than the surround).

The surround is kind of like the one in this picture on the floor with the balcony:

http://www.yandg.co.uk/1berkleystreet.JPG/1berkleystreet-full.jpg

 

[tonybhoy]

Have a look here,

http://www.worcester-bosch.co.uk/in...oilers-and-systems/greenstar-42cdi/literature


and download the 2nd document down and then go to page 16 of that document and read.Also read the note number 1 at the bottom of the page.

These are instructions for a WB 42 CDi however these are generic flue postitions for all boilers.

I've always measured the flue from the actual opening in the window BTW not the window frame or the surround like the one in your picture.

 

[lukens]

I already have that very document, which is where I was getting my measurements from.

My confusion that there wasn't sufficient space in it's current location was because where I initially wanted to move the flue to when running it from the store room was higher than it's current position, in that place there is another drain pipe that comes out and joins the main pipe, so spacing would have been tighter. It would also have been using 125mm flue rather than 100mm flue, as it would be covering a greater distance. When I checked again it looks like it should all be fine (though only just) in it's current position.

This is just rough measurements based on a photo though (and known measurements of elements in the photo), so I will have to try leaning out the window with a tape measure at some point to check more accurately.

 

[tonybhoy]

Just measure 300mm from the inside of the room from the window opening.But bare in mind that the boiler will be at least 450mm wide so the flue is always going to be in a safe position given the size of your window frame.

BTW,that size is to the side of the boiler flue nearest to the window opening so to the center of the flue it will be 350mm approx from the window opening.

Just had another look at your pic.Those windows are sash windows so you might be able to get the flue closer to the window (middle) than the 300MM if you need to because sash windows don't really open fully if you catch my drift.There is always a part of the window that is closed.

Sash windows do open fully however but only to clean them,it's not as though your going to have them in that position when the boiler is on (for any legnth of time) so it really is a judgement call re the flue position but I would always refer to the manufacturer in that particular situation.

 

[wiggikins]

Instead of all this typing just consult a registered gas installer in your area= sorted.

 

[lukens]

People opposed to typing really shouldn't use internet forums.

Seriously though - with that kind of attitude, what's even the point of such a forum, surely all questions asked on here could be answered by consulting a local trades person.


Obviously I'll need to consult a registered gas installer eventually, but I always like to get a head start on such things. I find it a lot quicker and simpler (and much less stressful) to do some research on the internet first, so that when it comes round to asking someone, I know what it is I'll be asking them.

 

[tonybhoy]

People opposed to typing really shouldn't use internet forums.

Seriously though - with that kind of attitude, what's even the point of such a forum, surely all questions asked on here could be answered by consulting a local trades person.


Obviously I'll need to consult a registered gas installer eventually, but I always like to get a head start on such things. I find it a lot quicker and simpler (and much less stressful) to do some research on the internet first, so that when it comes round to asking someone, I know what it is I'll be asking them.

With the greatest of respect thoughif you were asking me these sorts of technical questions face to face I would tell you to do one