Not sure which boiler to get...

[hamant]

Hi all,

I'm looking to replace my existing boiler for a new combi thereby eliminating the need for the water tank in the loft and cylinder in the airing cupboard. The thing is, I've no idea which one to get, how many KW's it should be and how much water flow i need.

I used this: http://www.sedbuk.com/whole_house.htm to calculate the KW's and it said i needed 24kw. I'm not sure how accurate this is and wanted some opinions.

This is my current set up:

Washing machine in the kitchen
7 Rads
NO power shower

Does 24KW sound about right? What about the water flow?

I also wanted to know about the regulations...does a Corgi registered plumber have to install the boiler? And is there a certificate I should get from them?

Thanks in advance...

Ham.

 

[chrishutt]

Just on sizing of boiler, with combis this is almost always determined by what hot water flow rate you'll settle for. Heating loads are rarely anywhere near the hot water load (unless your house is exceptionally big and drafty).

Hot water flow rate is proportional to heat input, so your choice is usually 24 kW (10 litres/min) or 28 / 30 kw, sometimes up to 35 kW. A proper Corgi reg. engineer will explain this properly (if he can't, be suspicious) and will brief you on regs. documentation, etc.

 

[ChrisR]

I also wanted to know about the regulations...does a Corgi registered plumber have to install the boiler? And is there a certificate I should get from them?

Yes a corgi has to do it. He will get the installation recorded with building control. Without that your house's "service history" won't be right, which may matter in a few years time, on selling.

Oh , and I wouldn't go smaller than 28kW for the HW performance.