Flue in Conservatory

[gunnag]

I'm considering having a new conservatory installed at the back of my house measuring 5m wide and 3m deep. A Guardian insulated & tiled roof system will be used and the roof will be approx 2.2m high at the sides and 3.5m high in the centre.

Currently the area which would be the new living space in the conservatory has a horisontal flue exiting from the boiler in the kitchen. The flue is located on the side of my house and exits approx 30cm from next doors house and at 1.8m height.

The boiler is a Potterton Prima F40 and is 20 years old and will be replaced as part of this project by a new condensing boiler.

I have a few questions about the routing of the new flue which I hope someone can help answer:-

1) If the new boiler is installed in the same location, can the new flue exit the wall using the existing flue hole and then be routed 90 degrees upwards and through the Tiled conservatory roof? I was told by one gas installer that flues cannot be redirected vertically and the only option was to move the boiler somewhere else.

2) The current flue exits the kitchen wall approx 30cm below the ceiling. Is it permissable to have the flue go up vertically through the ceiling and then exit from the void between the ceiling and floor above? The room above the boiler is a small bedroom, if needed could the flue enter the bedroom and then exit the wall, I realise the flue would need to be boxed in and inspection hatches made available.

3) If any of the above solutions are allowed, how far above a pitched roof must a horisontal flue terminal be? I'm aware that vertical terminals exiting a room must be 30 cm above the roof but what about horisontal flues exiting above a roof from the house?

All info welcome!

 

[Gasguru]

It's a Yes to all your questions but....

You need to check the manufacturers clearances regarding the flue terminal to windows, adjacent walls, rooflights etc. Clearances vary between manufacturers.

Vertical flues are always more expensive both in parts and labour.

All boxed in flues must have inspection access points.

 

[Agile]

In theory the flue can exit the boiler horizontally, go through the conservatory and then at an elbow upwards to a proper vertical flue terminal.

But all these questions can be answered by your gas reg installer.

You dont say what your conservatory will be made of but if brick then the boiler could be fitted there with a vertical flue going up through the tiled roof if 600 mm away from any vertical walls and 300 mm from the boundary.

Tony

 

[spareshunter]

Agile has the best and most sound advice and he said:

But all these questions can be answered by your gas reg installer.

 

[gunnag]

Thanks for the replies, the conservatory will have two brick walls (one is the back of my house, the other is nextdoors house which is offset). The conservatory will therefore only have 2 glass sides.

Mounting the boiler in the conservatory is a definete possibility and it would only mean moving the boiler a few feet from the kitchen into the conservatory.

I was hoping to keep the boiler in the same position simply to keep costs down.

In the subject of cost, I'm considering the pros and cons of converting to a combi boiler. My current system uses a heat only boiler, hot water tank and rads together with a three way valve. Does anyone know whether converting to a combi would save money? My house is a small 3 bed with good insulation, the heating is off during the day as both of us are working, my gas bill is only about £500 annually. I have flushed the rads several times and have installed a magnaclean filter. Since my gas bill is relativly low, Im not sure what benifit a combi boiler would provide given the extra cost of installation, but I'm willing to be swayed if sufficient evidence is available.

All info welcome

 

[Agile]

I charge about £400 extra to convert to a combi.

I also advise NOT to convert to a combi unless only one or possibly two live there.

Tony

 

[gunnag]

Thanks Agile, actually it is only two of us, so sounds like simply replacing with a new condensing heat only boiler is a good option.

I was thinking about replacing the old boiler with a Worcester Greenstar Ri 12 which has the same heat output (12Kw) as my current Potterton Prima F40.

The other advantage with keeping the same setup is that at some point in the future I may want to install solar hot water. Reading the Worcester Ri brochure I note that the boiler supports solar hot water if the appropriate cylinder is in place.

 

[muggles]

There are much better boilers on the market than that, Worcester are a triumph of marketing over design.

Solar hot water is only any good for people who get a warm fuzzy feeling inside when they think they're doing something towards saving the planet. It ain't going to pay for itself, let alone save you money.

 

[Agile]

The boiler has no involvement with solar heated hot water.

Any boiler can be used.

It is the cylinder which can be changed for one which can easily be used for solar but there are many possibilities.

A normal solar installation with about 4m² of panels will provide hot water for 2-3 people for about six months of the year.

How much that is worth depends on many factors but perhaps £250-£350 pa if gas heated. More if electric heated.

Tony

 

[DP]

OP, you can upgrade controls to give you independent control of central heating and water. Just by replacing the room thermostat with a programmable room thermostat, you will be able to heat the water before heating comes on etc

I have seen what happens to radiators in conservatories when weather gets Baltic, boiler in conservatory not a good idea for me anyway

Have you thought of going vertical in the house and exit the flue higher up? That is what I did when we had the conservatory built

 

[gunnag]

Thanks all, decided to relocate the boiler by moving it directly upwards into the small bedroom above and mounted on the outer wall. The flue can then exit directly from the wall in the standard manner.

The boiler will then be hidden from view by building a cupboard around it.

 

[simond]

The Worcester range use a kind of vertical flue which directs the flue gases sideways on exit, rather than vertically.

This has an impact on clearances to adjacent walls with windows, and will massively increase the required distance from the 600mm Agile has assumed.

If you terminate your new flue horizontally, above the new roof, there must be a minimum of 300mm clearance to allow for buildup of snow, leaves etc.

Worcester have published a tech bulletin allowing horizontal flues to discharge ithrough a penetration in a pitched roof.

You really need to get a boiler installer specialist in for advice, ideally someone who fits your chosen brand every day, they can advise you. Someone with a Gas Safe ticket who does kitchens and bathrooms too may not have the product knowledge or experience for the more challenging installs.