Is My Boiler Too Small ?

Aletank

I have a new build 3 bed detached house, year 2000, with a conventional boiler system, hot water cylinder in the airing cupboard etc
My boiler is a Halstead Best 50, 14.65 kw Output, I have 9 radiators in the house.
The bigger radiators downstairs never seem to get properly hot down the bottom & in the middle. I've tried balancing them, flushing the system with a hose etc, I've always had the radiator treatment in the system.
I was looking on the Bosch Worcester website at the new boilers, the smallest one they have is a Worcester Greenstar 24Ri, with a 24 kw output.
I would of expected the house builders to of put the cheapest available boiler in.
Any thought greatly appreciated

Myser

Aletank wrote: »

The bigger radiators downstairs never seem to get properly hot down the bottom & in the middle.

This may be indicative of sludge in the system. How old are the radiators? Have you tried a chemical cleaner in the system to loosen sludge?

Aletank

The radiators are 13 years old same as the house & boiler, I think they are linked with mainly plastic 10mm pipe. I've always used Sentinal Inhibitor in the system & I've flushed the system with a hose, not much dirty water came out.
To be honest since I moved in 10 years ago (house was 3 years old) they've always been the same.

plumb1_2

House builders will always put the min boiler they can.
You have about 2.25kw for your hot water cylinder, the other 12+ is for the heating. Bet you have about 9/10 rads on that.

Aletank

plumb1 wrote: »

House builders will always put the min boiler they can.
You have about 2.25kw for your hot water cylinder, the other 12+ is for the heating. Bet you have about 9/10 rads on that.

Yeah 9 Rads, would you say the boiler could be too small then ?
Thanks

Ben84

Well, number of radiators doesn't matter. It's about the size of the house and how quickly it looses heat. You have to do the calculations to know, but to me at least, 14kW sounds like a reasonable number for a three bedroom house. It's similar output to mine, which is heating a three bedroom detached house (much older and single glazed) perfectly well.

plumb1_2

Aletank wrote: »

Yeah 9 Rads, would you say the boiler could be too small then ?
Thanks

Search online for heat calcs, measure your room size's, then add them up. Plus allow for hot water . That will give you the correct boiler size.
You can also check to see if your rads are the correct size.

southcoastrgi

It's taken you 10 years to ask this question :eek:

keystone

Aletank wrote: »

I was looking on the Bosch Worcester website at the new boilers, the smallest one they have is a Worcester Greenstar 24Ri, with a 24 kw output.

No the smallest regular boiler they do is the 12Ri and the next one up from that is the 15Ri. Don't confuse with the Greenstar 24i Junior which is the smallest combi they do. Combi boilers are sized for the DHW requirement not the heating.

I would of expected the house builders to of put the cheapest available boiler in.

That would be why you have a Halstead then.

Cheers

Aletank

southcoastrgi wrote: »

It's taken you 10 years to ask this question :eek:

haha, I've always been messing with them each winter, trying to balance, draining down the system etc

Aletank

keystone wrote: »

No the smallest regular boiler they do is the 12Ri and the next one up from that is the 15Ri. Don't confuse with the Greenstar 24i Junior which is the smallest combi they do. Combi boilers are sized for the DHW requirement not the heating.
Cheers

Greenstar 24Ri http://www.worcester-bosch.co.uk/homeowner/boilers/gas-boilers/greenstar-24ri

The Greenstar Ri Regular boilers are the smallest of our condensing boilers
The Greenstar Ri Regular boilers are used with a heating system that includes stored hot water in a cylinder