Plant room and moving boilers...

[madge1]

hi

we're having a side extension built, with an extended kitchen and dining area.

Due to the sloping nature of the site, there will be a void under the dining area of about 3.4m * 3m with a head height of about 1.65m. I'd like to use this space, and thought about moving the boiler from the kitchen to there; the boiler will need to be moved (in fact replaced) anyway, as it's on the wall coming down.

Is the idea of a plant room feasible? No building regs over head height in the plant room? Obviously there'll be extra expense with insulation of the room, and there'll be cost involved in the extra pipe work from the existing spot to the plant room (it'll move about 4m, possibly 7m).

What about the exhaust flue of the boiler though - we've an external wall it'll obviously go through, but the fact it's below floor height; will that be an issue? It'll have windows above it - presumably not an issue, as most boilers have upstairs windows above them. Any other building regs to think about; obviously there'll be an external door to the room.

Any idea of the rough cost of doing this? The extra pipe work and labour etc. It will in fact be closer to the gas main, so that's a saving, but the architect says the flue must be above all windows, and that alone'll cost 500 odd quid.

In case in makes much difference, our location is near Reading. Sorry it's all so vague; I'd thought I was onto a winner, but according to the architect I've not thought about the full ramifications (although obviously he phrased it slightly nicer...)

Thanks

 

[petertheplumber12]

It is impossible to give a firm answer since the sited position of boiler is not known, but there are definite instructions on where a boilers flue can and cannot be. This is a general guide without the picture:-
300 is in mm
A Directly below an openable window, air vent or any other
ventilation opening. 300
B Below gutter, drain/soil pipe. 150
C Below eaves. 200
D Below a balcony/car port roof. 200
E From vertical drain pipes and soil pipes. 75
F From internal or external corners. 300
G Above adjacent ground or balcony level. 300
H From a surface facing a terminal. 600
I Facing a terminals. 1200
J From opening (door/window) in carport into dwelling. 1200
K Vertically from a terminal on the same wall. 1500
L Horizontally from a terminal on the same wall. 300
M Above an opening, air brick, opening window etc. 300
N Horizontally to an opening, air brick, opening window etc. 300
Vertical Flues - minimum distance to edge of terminal mm
P Above the roof level (to base of terminal). 300
Q From adjacent wall to flue. 300
R From adjacent opening window. 1000
S From another terminal. 600
For a non condensing but for a condensing it is similar to this:-
A Below an opening (window, air-brick, etc.) 300 mm
B Above an opening (window, air-brick, etc.) 300 mm
C To the side of an opening (window, air-brick, etc.) 300 mm
D Below gutter, drain-pipe, etc. 25 mm
E Below eaves 25mm
F Below balcony, car-port roof, etc. 25 mm
G To the side of a soil/drain-pipe, etc. 25 mm
H From internal/external corner or boundary 300 mm
I Above ground, roof, or balcony level 300 mm
J From a surface or boundary facing the terminal 1200 mm
K From a terminal facing a terminal 1200 mm
L From an opening in the car-port into the building 1200 mm
M Vertically from a terminal on the same wall 1500 mm
N Horizontally from a terminal on the same wall 300 mm
P From a structure to the side of the vertical terminal 500 mm
Q From the top of the vertical terminal to the roof flashing As determined by the fixed collar
of the vertical terminal

 

[madge1]

Thanks Pete

Here's some of the plans; as you can see the void is large, and there shouldn't be an opening window near by

Untitled

• madge1
• 7 May 2013
• 1

there would be an opening to the void under the large window, and hopefully the boiler exhaust could come out of the cutback to the kitchen area (the wall that's 1.82m wide).

There's no window above this (on that wall) and the window in the kitchen area will be 1.4m away, and about 90cm up. Should be far enough away shouldn't it?

ta

 

[petertheplumber12]

With most boilers you can extend the flue within manufacturers guidelines and that could allow you to put the flue terminal where it would be acceptable, just make sure the boiler is new enough to still get flue spares.

 

[madge1]

oh I appreciate everything's possible with cash; just wondered if you knew of any building regs etc that would restrict it for a reasonable amount of money; 20ft long flues for instance

 

[Dan Robinson]

I I can't see it being a problem from the picture. You might even get an unvented cylinder in there.

 

[petertheplumber12]

As long as the opening window is more than 300mm away from the flue terminal either to the side or above it will be acceptable, but terminal should be brought above ground level anyway by at least 300mm and then it would need a terminal guard (basket),

 

[madge1]

Cheers Pete; great answer, and just what I was after.

And Dan, thanks for the response. Have thought about that to be honest, but with a nice new lovely combi it should be provide enough waterflow (the pressure is pretty good, despite being at the top of the hill).

ta both

 

[Dan Robinson]

Pressure is not the same as flow.

What output combi is specified? And do you understand the performance chart?

 

[madge1]

we've not specified one as yet, but I'd like something with about 17 litres per minute. Probably over specced for 1 bath/2 shower, but better safe than sorry (although I know it'll struggle to do both together)

 

[Dan Robinson]

No conventional combi will do that.

You'll need a storage combi like a Vaillant 937 or Glow worm Ultrapower.

Personally i'd do a small unvented cylinder, and if the boiler is under the kitchen, use a combi to give hot water to the sink/utility.

 

[madge1]

oh i'm sorry; I thought a Worcester Greenstar 38Cdi would do 16.4 litres per minute.

At least, that's what their website says

 

[Dan Robinson]

It will, but only at 35º temp rise. So in winter you're filling your bath at say 40º.

Its minimum heating output is 9kw too which is far more than you will need for most of the year.


Take a look at the Atag A325ecx.

 

[madge1]

thanks, I'll have a look

 

[Dan Robinson]

The main issue with combination boilers is they get sized for hot water with little regard for heating and thus spend most of their operating life cycling on and off.

The advantage of a separate cylinder is you can size the boiler to the house and get better efficiency and reliability.