Boiler flue and bathroom ventilation sharing same chimney?

[curious99]

Hello,
Sorry if I am asking a stupid question.
Can one install a boiler pipe/flue and a ventilation for an internal bathroom - both in the same chimney in a Victorian property? (I recon it could be at least 10m to the chimney top, possibly much more.) I am willing to consider expensive options.
Many thanks

 

[simond]

That's an interesting question.

If there are two separate flues within the chimney stack, then possibly.

You could use a exhaust only flue system for the boiler, such as the one sold by Viessmann for use by their boilers. They also do a system for combustion air for the boiler, but this could be compromised by vitiated (ie: not clean) air from another terminal, so is verboten.

Then you could in principle connect the other flueway as a ventilation exhaust duct.

If these elements were mounted on a horizontal wall they would need to be a set distance apart, but for chimney stacks the requirements are less onerous, because it is accepted that they are designed for multiple exhausts.

However, if we were going to be the installer, we'd want to check with the boiler manufacturer and possibly building control because the room vent is not a normal use of a chimney outlet and therefore isn't accepted practice.

 

[curious99]

Simon,
thank you so much for answering so quickly.

If there are two separate flues within the chimney stack, then possibly.

It is a subdivided Victorian property, so I would be reluctant to interfere with neighbours' flues. I prefer first to look into the option of using just one chimney.

Can I fit a narrower boiler flue all the way vertically inside the chimney, and have the bathroom vent to open into the remaining space of the chimney? Given the age of the property (1870s) I imagine is it type 2 chimney, but I am not sure. I jus thope there could be enough space for two tubes. Or am I terribly wrong?

(I've read that Keston do narrow flexible flues, but if someone could recommend a more reliable maker which could allow for long flexible flues, that would be a very nice.)

However, if we were going to be the installer, we'd want to check with the boiler manufacturer and possibly building control because the room vent is not a normal use of a chimney outlet and therefore isn't accepted practice.

The bathroom is already ventilated into the chimney, and is "historic". Would that be still a problem? If not, could we now use the same chimney to fit a boiler flue?

And of course an advise for a suitable boiler make would be very helpful (given that we have to go all they way up).

Thanks a lot in advance