New central heating advice full new system

[macackau]

With out carrying out a heat loss survey I would be fitting a system boiler rated somewhere between 15-18KW and a 250 litre unvented cylinder such as a megaflo. Make sure the people you use are gas safe registered and G3 qualified to install the cylinder. With 2 bathrooms and the chance to install from scratch I wouldn't bother with a combi.

 

[Lee1981]

Hi macackau thanks for the advice going to look into all options, going out it the wife this week to look at bathrooms as when heating engineer comes I can tell him what I am fitting. It looks like in one bathroom there will be a bath with over head shower. And in the second bathroom there will just be a walk in shower, so the highest demand will be running 2 showers at same time. As I said before I have no experience on heating systems. With a system boiler would I get instant dhw hot water at the taps when I need it or do I have to heat it up prior. Just I no my wife will be wanting intant hot water.
Thanks for the reply

 

[macackau]

You'll be hearing and storing but if it's a well fitted mains pressure unvented cylinder it'll be pretty quick to deliver hot water. Could install a secondary circulation loop to make it near instant.

 

[Lee1981]

Ok thanks macakau great advise will discuss this option with the heating engineer when he comes out
Thanks again

 

[joni os]

Wise words from Lee regarding danger of still. Brandy, 40 proof on Xmas pudding, no comparison to 80 proof distillate on wok burner. Vapours highly volatile, like methane. Angels dancing on kitchen ceiling not recommended.

 

[Sparkgap]

Depending on age of the property, rule of thumb suggests about 4BTU/cu.ft or about 40W/cu.m in each room. That would probably mean your rads will be a little bit oversized if you don't want to go for full heat loss calcs but at least you can always turn them down!
Sizing systems on 20C flow/return temp drop you'd get about 5kW on 15mm pipe, 15kW on 22mm and 31kW on 28mm.