Enough space for a flue?

[Easyontheedgey]

I have a Powermax 155 (unpopular as it is) which is approaching the end of its life. It's in a flat, about 8m from an external wall.

Ideally I would like to replace it with a gas boiler (rather than electric system) with something that provides a good flow of water like the Powermax, and situated in the same location as existing boiler.

The issue is that the recommended angle for a flue for a condensing boiler requires more space than the current ceiling void of about 6 inches. I'm told the flue should slope about 2 inches or so for every metre. I don't want to build boxing or drop the ceiling to achieve this.

If I put a new boiler on the external wall where the existing flue exits the flat, this will require a pump to take the water discharge away to a waste pipe, as there is not one in the same room. Since it's a bedroom, the noise of a pump (and use of space) would not be ideal, although I think the pipes could easily be routed back (via the ceiling void) to the location of the existing boiler to connect to existing pipework.

I was wondering whether a condensing boiler could be fitted in the existing location but with a flatter angle of flue. I was told by one plumber that this could be done and the only implication would be that the boiler would be less efficient as less condensate would flow back to the boiler. This seems to make sense as any angle should enable water to flow back albeit at a slower rate (therefore the protection against rust must be sound).

I'd be grateful for your thoughts on using a flatter flue including whether specific boilers might be best for the job. Or will I need to go electric?

Thanks

PS pls send me a message if you are based in central/SE London and interested in quoting.

 

[Dan Robinson]

I was told by one plumber that this could be done and the only implication would be that the boiler would be less efficient as less condensate would flow back to the boiler. This seems to make sense as any angle should enable water to flow back albeit at a slower rate (therefore the protection against rust must be sound).

Your first plumber is a prat.

You need the fall as stated in the MI's.

The pumps are not that noisy. I would just put the boiler in the bedroom and put it in a box with a bit of sound proofing.

 

[mickyg]

I was told by one plumber that this could be done and the only implication would be that the boiler would be less efficient as less condensate would flow back to the boiler. This seems to make sense

No it doesn't make any sense and if he honestly said that for gawds sake dont employ him!

 

[swbjackson]

Some manufacturers offer a twin flue option which, being smaller pipes, may give the required fall back. Current legislation requires that access panels are sited to allow for a visual inspection of all flue joints so a system using longer flue pipes will be preferable.