Worcester Bosch 24si II - venting a cupboard

15 Jan 2007
Reaction score
United Kingdom
I have just fitted my kitchen and want to put my existing boiler into a cupboard. The model is Worcester Bosch 24Si II (manual http://www.worcester-bosch.co.uk/index.php?fuseaction=literature.detail&con_id=5050&from_id=5029).

Having read the manual, once the boiler is in the cupboard it will not have the recommended clearance for a non vented enclosure, but the manual says that if this is the case 2 vents must be provided, one high and one low and need to be 264 cm/2.

Required clearance
Top 15cm
Sides 8cm
Bottom 20cm
Front 24cm

Actual clearance
Top 30cm (as top of cupboard has been cut away for flue)
Sides 1cm
Bottom 10cm
Front 1cm

What I'm planning is to cut a hole on the underside of the cupboard for the lower vent, and where the top is already open to allow the flue out of the cupboard, make sure this is at least the required size.

Would this be OK? I'm a little concerned about the 1cm clearance on the sides, even with the vents. If this is still a problem, could I drill several holes in the side too to increase air flow?

Also the manual refers to BS6798 and BS5440 Part 2. Would this be OK for these standards?

Many thanks for your help.
Sponsored Links
it will be classed as not to current standards.

ventilation is not your only concern. the enclosure may hamper servicing or repair of the boiler. if you do go ahead dont whine like a girl if someone refuses to work on it for poor clearances.
The cupboard is removable when the boiler needs servicing so that shouldn't be a problem.

Is that the only reason it would be classed as not to current standards or due to vents/clearance?

Most importantly, would it be safe?
as a general rule the compartment has to be either completely open top and bottom with the correct clearances or if its completely enclosed have the correct size vents installed and have the correct clearances.

from what you are telling me you will be ncs for both vents and clearances. in the real world neither is likely to make an impact on safety but the mi's and regs say its ncs so thats what its classed as.
Sponsored Links
OK I get what your saying, although with the cupboard practically open at the top and with the vent on the underside being at least 264 cm/2 surely that makes it OK regarding the vents.

Clearance is another matter. Unfortunately there is no reference to the clearance required in a vented cupboard, so that's my main concern.

If it is ncs as you say, would this affect my insurance etc?

I think I'll take a few picture when I'm back as hopefully this will make things easier.
its a bit of a grey area this and most folk cant get their head round it.TBH im not entirely sure its not just BG being gits.

if the compartment is completely open top and bottom, i.e. absolutely no material on the upper and lower surfaces then its not really a compartment, more of an enclosure. it doesnt need vents as its not a compartment. you still need to observe clearances.

if it has a top or bottom then it is a compartment and needs the correct ventilation and clearances.

if its a mixture of both like yours then its a compartment and yours wont have a top vent, crazy i know but i dont make the rules. if i visited your house you would have a nice shiny ncs letter. if joe plumber visited you might not.

like i say this is the way i do it and im sure the will be someone along to disagree with me very soon. you never know you may get to watch a 5 page argument unfold. :LOL:

im not aware of any problems with your insurance regarding this, im not your insurance company though.
OK here are a few snaps of the boiler and cupboard.


This is the top. you can see the area already cut out which would be an area greater than that required (307cm/2), but I am going to enlarge this by cutting away the extra outlined with the black line.


And this is the underside. I will be cutting the section in black out, which again will provide above the required area.


So what do you think? Does this look safe? Is there anything else you can suggest?

its ncs. nothing about that is right.

apart form being a pain in the ars e to remove there is nothing inherently unsafe about the compartment though.
Cool, to be honest, removing the cupboard may be a pain when it needs servicing, but I can do that without too much hassle.

As long as it's safe, I'd rather have to remove it every now and then, than have an ugly boiler standing out in my new kitchen.
I know this post is from a while ago but ive just joined & read it.

My boiler is in an actual bedroom cupboard (onto an outside wall). There are no windows or vents in the cupboard. It is a large cupboard & has been serviced by British Gas so i assume this is safe enough?


DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local

Sponsored Links