Selecting boiler for CH system.

[armyash]

Hi guys, if doing an install, how do you select boiler size?

 

[AWheating]

the one that fits in the cupboard



it depends on what type of boiler your fitting?


in laymans terms:

a combi is sized on hot water requirements

a system/heat only is sized on total system demand

whats it for?

google whole house method for one way of doing it.

 

[armyash]

the one that fits in the cupboard



it depends on what type of boiler your fitting?


in laymans terms:

a combi is sized on hot water requirements

a system/heat only is sized on total system demand

whats it for?

Thanks for the reply, I'm not actually doing an install yet generally speaking I meant. Been doing installs but that is all decided and I just put it in haha. I was wondering how it's all decided.

 

[AWheating]

HHIC » Domestic Heating Design Guide

Design Guides available at CorgiDirect

there are some good books around if you want to do some reading i can recommend the top one.

 

[armyash]

Thanks!

 

[Dotty]

Happier with this in the private forum.

Really don't want the fish trying to tell us our jobs.........

 

[armyash]

Happier with this in the private forum.

Really don't want the fish trying to tell us our jobs.........

Sorry thanks for moving. twice in less than a week :blush2:

 

[arran197]

when deciding on a combi, you need to check the cold mains flow rate. If you buy a boiler rated to work over the flow rate of the mains, there's not really much point as it won't be needed anyway.

 

[Derek Hardman]

Whole house boiler sizing method for System or heat only
Flow rate and hot water demand for the family if installing combination.

 

[armyash]

To be honest, it's going to be a while until I do this for myself was just looking for a heads up but will get my head in one of the books available so that when the time comes I know what I'm doing.

 

[Simon F]

City Plumbing Supplies - Find your nearest CPS branches

this link has been posted many times so you might already have it,
very useful, easy to follow to get a quick heat loss figure.
do the figures for each room then you know what KW boiler you need.
if its for a system/open vent add another 3kw for the hot water cylinder.