Plumber wants 60% deposit upfront

nofoollikeold

Rather than having the highest Kw boiler you can get, its better to work out the Kw needed to heat the house - the heating load. This is the power required to balance the proprty's loss of heat to outside, plus an allowance (usually 10 to 15%) to get the rooms up to temperature from cold. Then pick a boiler which can modulate its heat output down to that load, but which still provides adequate power to heat the hot water.

The ability to heat hot water at high flow rates is a function of the boiler's maximum power. However, if the heating output from the boiler is much higher than necessary to make up the building's heat losses, the boiler will cycle on and off on central heating, which wastes gas. So a compromise is needed.

For example, if the heating requirement is 15Kw, find, say, a 30Kw boiler which can modulate (or be adjusted down to) 15Kw for heating.

Surrey_heating_services

Hi all
Combis are sized to the flow rate you have on the mains cold water not on how many rads you have!!
If you have a powerful mains supply ie 18litres per min then a 42 is right personally I'd go with the 38 as the 42 is only slightly better but is a few hundred £ more

It really makes me mad when ppl post the 2 penny's worth when they don't know what they are talking about!!

Regards
Richard
Btw I'm a Worcester Bosch accredited installer

Marktheshark

With BG allow 30% for hidden extras, they find problems with everything, wiring, water supply and blame the last dodgy trader, they upsell, add on and mark it up.

The Kwikfit of the heating world.

chappers

southcoastrgi wrote: »

If he's spec'd an Ariston I wouldn't give him the job let alone any money

Was just about to say the same.