Change to System Boiler but keep existing H/W Cylinder?

[Glyn1959]

Hi, I would appreciate some advice please. I need to upgrade my gas boiler to serve additional radiators.
I currently have a conventional system (tanks in loft) and was considering a system boiler.
Could I change to a system boiler while still using my existing cylinder or will I need a new cylinder along side the new boiler?
I have a plumber coming out to advise but I always like to have some knowledge/advice beforehand.
Thanks

 

[JohnD]

Could I change to a system boiler while still using my existing cylinder

Yes.

If you have very good incoming flow from your water supply pipe (say, 20 litres per minute) then you would get even better results from an unvented cylinder, but this would cost more.

 

[stem]

I currently have a conventional system (tanks in loft) and was considering a system boiler.

I suspect from that comment, that your 'driver' for changing to a system boiler is to get rid of the tanks in the loft. If you did install a system boiler the smaller of the two tanks (~4 gallons) would go but if you were to retain the existing hot water cylinder then the larger one (~20 to 40 gallons) would have to stay as this will be provide the cold water that fills and pressurises the cylinder.

An unvented cylinder as per JohnD suggestion above doesn't need one though, as the expansion of the water when heated is catered for by an expansion vessel.

 

[ianmcd]

I think you might be confusing a system boiler with a heat only boiler which is what you have at present, you can just change to another heat only boiler to accommodate the extra radiators if you want and keep all the existing tanks .

 

[JohnD]

how do you know your old boiler won't do the job?

 

[Glyn1959]

JohnD: We have added one radiator since the boiler was installed and the plumber then, along with 2 different BG plumbers who have performed the annual boiler service have all said the current boiler is running at it's max and could not cope with additional rads;
Stem: You are correct. Removing the worry of the tanks in the attic over winter was a consideration. Thanks for explaining! I thought that with any system boiler there would be no requirement for any tanks in the attic.
Ianmcd: I might end up simply upgrading the boiler (but thought I would consider killing 2 birds with 1 stone)
Thanks all

 

[scoobydo123]

Highly doubtful adding rads will "max your boiler out" and these comments about "already at max" could well be rubbish. Does your current boiler (please supply make and model) currently heat your home to a comfortable level (this assumes everything after the boiler is set correctly including radiator balance). Sounds very much like these people so far are out to get a new install that might not be required.

 

[Nige F]

2 different BG plumbers who have performed the annual boiler service have all said the current boiler is running at it's max and could not cope with additional rads;
l

Well they would.

 

[ianmcd]

What boiler do you currently have and how many radiators ?