Twin flue pipes

[hard-work]

In a twin flue pipe setup with a boiler in a well ventilated basement (area of basement air vents larger than air intake pipe), only the exhaust pipe needs to be taken to outside with the air for combustion drawn in via the well ventilated basement. Common in small commercial setups. Do many domestic makers state the air has to come from the outside only, via a pipe?

Most of their blurb all has diagrams of air intake to the boiler using pipes to outside, with no mention of taking air from a well ventilated basement, garage, etc.

This setup using a Navien is taking the air from the well ventilated room:

 

[Razor900]

The answer is in the A's, B's and C's........

 

[Razor900]

And everything you need to know is in the instructions

 

[hard-work]

Is it? mmmm No. Even with Intergas.

 

[Jackrae]

Video is from USA and their installation standards don't apply in UK.
Simple question - what's a "well ventilated basement" ?

 

[hard-work]

What are the standards in the UK? I have seen this setup in light commercial in the UK.
Well ventilated? The area of the 50mm air intake pipe is far less than the area of the outside air vents.

I just want the views of those who have had experience of this, rather than random comments.

 

[muggles]

The Americans have interesting attitudes to all sorts of standards, bless 'em. In the UK domestic market, the air intake must come from the same pressure zone as the exhaust, which realistically means that they both need to terminate in the same location. There have been one or two exceptions to this, but not many. One example would be Vokera, who produced a chimney liner kit for a while that drew air from the room

 

[Razor900]

What are the standards in the UK?
I just want the views of those who have had experience of this, rather than random comments.

I've given you the answer. If you ask nicely someone might explain it to you....

 

[bernardgreen]

Assume the boiler is fitted on the east wall and the exhaust flue is pointing east. The ventilation to the room is on the west side of the building.

Wind coming from the east would cause the air pressure on the exhaust to be higher than the pressure in the room. In strong winds this pressure difference could overcome the fan and force gas and/or fumes to come out of the air intake and into the room.

What ever happened to the expression " balanced flue "

 

[hard-work]

It’s clear that all your threads show a lack of experience.
You seem to ask a question with the insinuation that you know what you are talking about, how far from the truth that really is.

You think too much of yourself. New on the forum. Another Dan Robinson here. So you never answered the question. Which is....

Do many domestic makers state the air has to come from the outside, via a pipe, only?

 

[hard-work]

Assume the boiler is fitted on the east wall and the exhaust flue is pointing east. The ventilation to the room is on the west side of the building.

Wind coming from the east would cause the air pressure on the exhaust to be higher than the pressure in the room. In strong winds this pressure difference could overcome the fan and force gas and/or fumes to come out of the air intake and into the room.

What ever happened to the expression " balanced flue "

Bernard, it would be one weak flue fan for that to happen.

 

[hard-work]

I've given you the answer. If you ask nicely someone might explain it to you....

You have answered nothing. Intergas do not for sure.

 

[hard-work]

The Vitodens allows the exhaust to outside with air drawn in from the room the boiler is in. So only one pipe used.

Page 32 shows air from inside the room.

viessmanndirect.co.uk/files/a434c2a8-5a1c-4a28-9d08-a35400f7cfbe/flue%20technical%20guide%20up%20to%20150%20kW.pdf

 

[bernardgreen]

Bernard, it would be one weak flue fan for that to happen.

It does not need to be a strong fan if the boiler is designed to work with a balanced flue system. A balanced flue system means that both the exhaust and the intake face the same external air pressure.

 

[hard-work]

Bernard, I have seen air intake and exhaust pipes on opposite walls, although not in a domestic setup. I have seen many odd commercial setups - fans in flue pipes using atmospheric boilers and the likes. It is domestic setups I am interested in.