Boiler size query

[ceolmar]

Hi Guys

I have done several on-line boiler sizing checks and they generally indicate that I need a 10KW boiler to supply the 'right' amount of DHW and CH.

However, having scouted around for a boiler I cannot find one small enough! For example the Baxi HE range gives a heat input figure of 33Kw. Can I assume that I'm looking at the wrong number on the tech sheet? If so, what should I be looking for?

Just out of interest, does 10Kw sound right for a 3 bed semi?

many thanks

 

[Bahco]

Hi Guys

Just out of interest, does 10Kw sound right for a 3 bed semi?

If you have only 2 radiators then yes

Suggest you look at 24 or 28 Kw boilers.

 

[namsag]

Average 3 bed semi needs about 40,000 btu to 50,000 depending how fast you want the house warmed up and to a decent heat . New shoe box 3 beds with good insulation and smaller size can get away with 30,000btu... 3413 btu`s equals 1 kw.. So unless your after a combi a 15kw boiler would be ok

 

[kevplumb]

i allow 10 kw for h/w load

 

[namsag]

10kw is a far too much, a 27" immersion heater will heat a tank of water in 30 mins and they only give out 3kw. With modern fast recovery cylinders with high efficency coils allowance for HW is practically none existant during normal central heating operation

 

[kevplumb]

 

[doitall]

10kw is a far too much, a 27" immersion heater will heat a tank of water in 30 mins and they only give out 3kw. With modern fast recovery cylinders with high efficency coils allowance for HW is practically none existant during normal central heating operation

Rubbish

we allow 15 kw albeit slightly larger systems.

 

[kevplumb]

us old gits must stick together DIA

btw thanks again

 

[PEDANTICVINDICTIVEMAN]

8000 btu for HW whatever that is in Kw errrrr fiddel faddle grunt gasp 2.34 Kw

 

[kevplumb]

p*ss of ped
not even close

 

[htgeng]

p*ss of ped
not even close

A 'good' cylinder has a coil of at least 15kw capacity. You'd need that if you were constantly drawing off hot water! Not strictly relevant, but think about how piffly a 25kw combi boiler is at producing hot water...

 

[PEDANTICVINDICTIVEMAN]

I dont use good cylinders, only the crap the merchants sell.

 

[htgeng]

I dont use good cylinders, only the rubbish the merchants sell.

Done any megaflows?

 

[PEDANTICVINDICTIVEMAN]

And your saying that a cylinder needs 51180 btu's to heat up then, will have to be a meaty boiler to cope with the heating as well.

 

[PEDANTICVINDICTIVEMAN]

Not interested in doing "another" bloody course so dont bother with them plus more to go wrong, never had to service grannys hot water tank, any way there are mains pressure hot water cylinders which you dont need another certificate for.