How many BTU would old cast boiler have given to room.

Fenlander · 20 Feb 2010

Going to have a new boiler fitted soon by a RGI as part of a utility room & cloakroom revamp.

After he's finished a wall will be moved and a toilet compartment created which will include the new boiler.

First to work out the new rad I'll put in the utility room at a later date I wondered what the removal of the 25yr old cast type Thorn Olympic 38/50 will do in reducing heat input to the room... in BTU?

Second when the toilet compartment is created with the new boiler in it should I assume no heat gain to room from the modern A-rated boiler?

Last does anyone do tiny rads as it seems the toilet may only need 600BTU?

Thanks.

Whitespirit66 · 20 Feb 2010

Use a rad sizing calculator to work out a rad size for utility room.

http://www.radcalcs.com/

A single 600X600mm single rad will give you approx 600 BTU for the toilet. Yes, you will gain a bit of heat from the boiler. Fit the small rad with a thermostatic valve, so that you can control heat if its too much for such a small room

Agile · 20 Feb 2010

Modern boilers lose very little heat, perhaps about 100w.

An old boiler like the one you had was likely to be giving out about 2-3 kW !

Tony

Boilerman2 · 20 Feb 2010

Forget about the old boiler and it's heat gain into the room, just do the maths and calculate the heat requirement for theroom, Mears do a good calculator for this, Condensing boilers generally operate at lower flow temperatures than their predessesors, typically 70*c, so you will havre to do the maths!!

gas4you · 20 Feb 2010

About 2.5% of boiler output if conventional flue. Don't know your boiler though

Fenlander · 21 Feb 2010

Yep I'd done the calcs for the room but as we've modernised this house we've changed many of the rads for different reasons (style, position, size) and been able to consider our experience of living here for 16yrs knowing how each room feels as well as what the calcs say. Its a solid brick wall place in an exposed country situation so many standard online calcs don't get the right result.

So I was just trying to work out the heat loss from taking the old boiler away.

I think the comment about a 600x600 rad being OK for our need of approx 600BTU is a mistake in units. A 600x600 is not far off 600W but it's well over 2000BTU so far more than we need for the small toilet.

I can't find any tiny rads.... bit of 22mm up the wall perhaps!?

lifesagasman · 21 Feb 2010

a 400 x 700 towel rad doesn't kick out much heat

heatingeng · 21 Feb 2010

gas4you said:
About 2.5% of boiler output if conventional flue. Don't know your boiler though

nobody could answer this question ,anybody who has doesnt know the answer so there just making it up.

measure what the room requires as what somebody else said thats the only way .

Thanks

Fenlander · 21 Feb 2010

Ahh yes... just looked and a basic small one in chrome is only 600-700 BTU so that will do and match the neat new toilet.

Thanks for the idea.

lifesagasman · 21 Feb 2010

anytime

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How many BTU would old cast boiler have given to room.

lifesagasman

lifesagasman

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