I have a recently-installed Bosch Greenstar FS30CDi boiler to run 12 radiators and 2 towel rails and we are having problems. Is this boiler big enough?

Mrs R Vasey, January 2010

Your boiler is a 30Kw output unit and therefore can be expected to be more than adequate for a 5 bed house.

If you want to check that your boiler is suitably sized I suggest you visit www.sedbuk.com and use the 'boiler sizing calculator' link on the first page.

It will ask you for the length and width of the property and whether it is detached/terraced etc and what sort of windows you have. Only fill in the blanks, the rest is all calculated for you. It will come up with a Kw rating for the boiler, which we can calculate manually, but this thing is accurate within about +/- 5%.

If your boiler is big enough, then as the previous answer suggests, the problems lie with the installation.

simon at www.hwch.co.uk, February 2010

as long as all of the radiators are not really big then it should handle it no problem. if you're not getting them heating evenly then the system will probably need balanced to spread the heat around evenly. either that or the pump may be at fault or possibly pipe sizing too small.

Ian, January 2010