Boiler replacement

MouldyOldDough

We have a 15 year old Worcester Greenstar Junior 28i  combi boiler that has been pretty reliable (in recent years we have had a few pressure problems - resolved by an external pressure vessel) - however, now, it appears to be destroying internal seals (our heating engineer has has had to clear out pieces of plastic/rubber from the heating element !)

I am guessing that it will not be up to the extra radiators that a coming, extension will need ?

Do we replace it or fix the existing ?

What Brand of boiler is recommended for long life and reliability - another Worcester ?

FreeBear

MouldyOldDough said: I am guessing that it will not be up to the extra radiators that a coming, extension will need ?

Do we replace it or fix the existing ?

What Brand of boiler is recommended for long life and reliability - another Worcester ?

You need to add up the rated output of the existing radiators and add in the new ones for the extension. The Greenstar 28i is rated at 24-25KW (13.4KW for the low NOx version) for central heating (28KW for hot water). As long as your total heat demand for the radiators is lower, the existing boiler will be plenty big enough. In all probability, you could get away with a smaller boiler if you have less than 10 radiators... But combi boilers are sized depending on the cold water flow rate - Too smaller a boiler, and all you get is luke warm water out of the taps.

I have a cold water flow rate of ~10l per minute, and have a Viessmann Vitodens 050 30KW Combi due to be fitted next month. It should modulate from ~3KW up to 25KW for heating. Have about 13KW of radiators installed which keeps the house reasonably warm.