http://www.worcester-bosch.co.uk/homeowner/boilers/gas-boilers/greenstar-12ri
Hi all i am going to have a new boiler fitted later in the year we have a back boiler at the moment 31years old.
We would like to have a boiler on the wall .
Question's are
How close can i have the boiler to a outside back door
second Q how do i work out how big the boiler needs to be for the size of our house KW size
Thanks jacko

pretty sure the flue needs to be at least 300mm from a door for a fan assisted flue.

for the boiler size you need to do some calculations starting with the radiator sizes for the rooms then add them together.

http://www.radcalcer.co.uk/

Hope that helps

Cheers

Mark



[Edited on 21/1/14 by mookaloid]

Ours is right next to the back door.

Regarding boiler size to do it properly you have to do a heat loss calculation for each room, this takes account of the window types and construction of all fabrics I.e how much insulation you have.

The heat loss is calculated using the above info and your chosen design parameters you want say 21degrees internally when its minus 8 outside. For every degree lower than -8 you loose 1 degree inside.


Or you can do a rule of thumb to guess it like most plumbers do at 100w per square meter.

A lot depends on if you are keeping your hot water tank or getting a combi boiler. If combi it's really down to how fast you want your bath to fill, as this takes much more energy than the heating.

We want to keep the tank i don't like combi boilers they seem to go wrong a lot
The boiler will be about 1.5m away from the door so it look like it will be ok there

[Edited on 21/1/14 by jacko]

Hi,
The Worcester Bosch website includes the manuals for the boilers to download.
From memory this should inlcude the installation instructions with lots of diagrams showing the different flue arrangements you can have.
To get the required distance you may require an angled chimney, depending on where the flue exits. Not the prettiest solution but quite good at getting rid of the fumes.

Thank you all for the info and help i think i have it all in hand now

I have found out where i want the boiler it is in a good place for it
Thanks
Jacko