What size of boiler?

Dee_1982

I have decided that a gas combi boiler is my best solution for heat and hot water. Now my question is what size of boiler do I go for?
I have the flat split into 3 zones, zone 1 living room/kitchen, zone 2 master bed room, and zone 3 hallway.
I will be running a 2 bedroom flat, 1 kitchen sink, 2 bathroom sinks, 2 mixer showers, 1 bath, 4 main radiators, 1 small radiator, and 2 towel warmers.
What size of combi boiler in kw would I need to run that system from as I have been getting mixed reviews.
And any advice on heating controls that I should go for also would be great.
Thanks for any help.

The larger the kw output the better the hot water output(and the larger the gas supply needs to be), the heating side can be range rated to meet your heating requirement.

You first need to establish if your home is suitable for a combi, this is determined by mains water pressure/flow and also will you be happy with the different working characteristics with a combi as opposed to stored water which is more suitable to multiple taps turned on at the same time.

DGOBS

Can't see many combi boilers coping with both showers at the same time.

Dee_1982

gary71 wrote: »

The larger the kw output the better the hot water output(and the larger the gas supply needs to be), the heating side can be range rated to meet your heating requirement.

You first need to establish if your home is suitable for a combi, this is determined by mains water pressure/flow and also will you be happy with the different working characteristics with a combi as opposed to stored water which is more suitable to multiple taps turned on at the same time.

What do you mean by the gas supply being larger? Do you mean it's going to less economical?
Any ideas on boiler sizing?
What would work best in a flat situation? I am at the installation stage so I can go with whatever heating source.

shane0007

The larger the output of the boiler, the larger the diameter of the pipe supplying the gas to the boiler needs to be.
Boiler size will need to be in excess of 30kw.
You need to test the quality and pressure of your incoming mains. What is the level of hardness and what bar is the mains pressure? How consistent is this pressure, does it fluctuate at differing times throughout the day? Will the showers be operated at the same time?

Dee_1982

Dee_1982 wrote: »

What would work best in a flat situation? I am at the installation stage so I can go with whatever heating source.

I wouldn't use a combi in your case due to the multiple taps/outlets you have, to test hot water you should be able to open all the hot taps and get hot water, you do that with a combi with to many taps open and you'll be getting out the torch and looking up the spout to see where you're waters gone:eek:.

I would go for stored water maybe a unvented cylinder if you have the room and the water pressure, it's easier to meet the requirements of multiple taps/outlets once the requirement is identified.