Installing a combi boiler on a working chimney?

[karljones]

Can someone help...

I am having a new heating system installed in the next few months. I have had a number of tradesman quote for the job and am getting completely different views on the location of the actual boiler. It is going in the roof.

My roof is pyramid shaped so I have no solid wall. I have 2 open fireplaces almost back to back which join in the roof and become 1 chimney stack. In the roof the chimney is about 6 feet across at the ceiling level then after about 3 feet high it then comes in at 45 degrees on each side until its about 3 feet wide and then goes through the roof.

Can the combi be installed onto this working chimney. Both fires will have wood burners which will be used. One person has said yes, one has said it will need a heatproof board on the chimney first and the final suggestion is have the boiler mounted on a normal board spaced a couple of inches away from the chimney.

Who is right?

Thanks

 

[muggles]

My own view would be that you can install it onto the chimney breast provided the chimney is of a suitable construction and the fixings & fixing holes do not penetrate into the chimney itself (to prevent leakage of smoke). I don't see why a heatproof board would be needed as the chimney is inherently heatproof anyway, I would however like to see the boiler mounted on a flat surface so some sort of board would be good if the face of the chimney is a bit knobbly. Failing that you'd need to create a timber frame elsewhere in the loft from which the boiler could be hung. This would require a heatproof board.

You've probably already worked out that the flue can't discharge into or through the chimney, but I'll mention it anyway. The flue terminal will also need to be a certain distance horizontally from the outlet of the chimney on the roof.

If the boiler is going in the roof it must be installed with a continuous fixed floor between it and the loft hatch for access. There must also be a permanent loft ladder

 

[karljones]

Thanks muggles

The chimney itself is just normal brick construction and is as flat as a normal brick wall, so I would say there would be no problem with mounting. I don't remember it being particularly knobbly!!

Just 1 question regarding the flue.. I was aware it couldnt discharge into the chimney, but no one has mentioned about it being any minimum distance from the chimney outlet. Do you know how far?

Thanks again

 

[Agile]

Most boilers can be fitted directly to a brick wall. If its severely irregular them it can be cement rendered or plastered to give a flat surface Or a fireproof board can be fitted.

One problem can be that there is insufficient vertical space to move the vertical flue to be far far enough away from the external stack ( which may not be directly over the internal stack ).

The flue has to use 45 degree bends and the nearest part of the flue usually needs to be at least 600 mm from the stack outside.

None of this is any serious problem. What is a potential problem is that access to the top of the roof will be needed. Depending on who does it could involve scaffolding and the minimum would be a roof ladder and someone agile!

Tony

 

[karljones]

Thanks Tony

The chimney is close to the centre of the roof, so I have between 6 and 7 feet clearance. The chimney is straight through the roof. There should be plenty of height to get the flue 600mm from the chimney outlet.

One problem I can see is the outside roof access and agile installer. Just picture who you would need to be doing the job.... who I have in mind for the job is the complete opposite!!!!

Thanks again

 

[ALEC1]

scaffolding is a requirement to work at heights....you aren't expecting an installer to work off a ladder are you?

 

[karljones]

Hi Alec1

Not at all - it was more of a joke.. The installer I have in mind isnt exactly what I would have called agile!!!

Chimney need repointing anyway so it could be done at the same time. I hadn't thought about working on the roof side but now its been mentioned I will ensure scaffolding is there

Thanks

 

[JohnD]

It is going in the roof.

Why?

 

[karljones]

Not really got the room anywhere else.

Kitchen is not really that big and didn't want to loose a cupboard for the boiler. At the minute the hot water tank is in the airing cupboard in a narrow bathroom. When the tank is gone I am opening the cupboard out and using the extra space to fit a bath across the width (hard to explain, basically no airing cupboard)

Where else could it go? I have a garage but its about 10 feet from the house

 

[JohnD]

compared to the amount of room you will gain/lose (approximately one kitchen wall-unit) you seem to be going to a vast amount of trouble and expense, not to mention the awkwardness of clambering up to the thing when in service (or nor bothering).

Especially when you get a broken leg or become infirm and can't go up the ladder.

 

[ALEC1]

I suspect the boiler and flue will need changing slightly more frequently than the chimney repointing...

have you considered that?

 

[karljones]

Interesting point about becoming infirm or having a broken leg. I am only 37 and if either happens the boiler will be the last thing on my mind!!

Back to the boiler.... the gas and water enter the house at the same point in the kitchen. If I put the combi in the roof on the chimney it is almost directly above this point. I already have a loft ladder and attic is boarded. I really cant see any benefit it not putting it up there, unless I have missed something obvious

Thanks

 

[karljones]

Alec

How often does a flue need replacing. Do you know if its checked during services. I know very little about central heating, hence the questions on here?

Thanks

 

[ALEC1]

flues have to be replaced when boilers are changed....ok that coud be as long as fifteen years if you get the right boiler installed properly...


Most houses in germany have boiler rooms on the ground floor, thats because its a sensible location, I think boilers in the roof is a silly place to be honest...

 

[swbjackson]

scaffolding is a requirement to work at heights....you aren't expecting an installer to work off a ladder are you?

There are other systems for roof work. We used to use Tetra equipment which allows you to work safely for short durations on roofs.

Have a look at http://www.workingatheight-safety.co.uk/