Hi folks,

I am thinking of changing my ancient back boiler heating system
(gravity based, pumped). The reason is to get instant hot water, reduce
bills and stop the hassle of pilot lights going out or wasting gas etc.


The options that i have include
1) Converting to a fully pumped system. I asked one guy about likely
costs and he quoted me 'thousands'. Also, a fully pumped system won't
get me instant hot water although the new boiler would probably save
money on gas bills.

2) Just bin the old back boiler and invest in a combi (or condensing
combi). However, since my property is 'large-ish' (3 bedroomed terrace,
with additional 2 bedrooms in loft, 1 bathroom) - i'm worried if a
combi can cope with it. I certainly dont want cold rooms in the loft!
Price wise, i reckon i can get the boiler for around £600 and get it
installed for another £600-ish. This compares favourably with option
1) above.

Do i go for a high output 30HE condensing boiler, since this seems to
be more powerful than other 24HE boilers, or will a standard
non-condensing combi do the job?

Advice appreciated.
Ta.

On Fri, 03 Feb 2006 06:48:39 -0800, Nis wrote:

Hi folks,

I am thinking of changing my ancient back boiler heating system
(gravity based, pumped). The reason is to get instant hot water, reduce
bills and stop the hassle of pilot lights going out or wasting gas etc.


The options that i have include
1) Converting to a fully pumped system. I asked one guy about likely
costs and he quoted me 'thousands'. Also, a fully pumped system won't
get me instant hot water although the new boiler would probably save
money on gas bills.

2) Just bin the old back boiler and invest in a combi (or condensing
combi). However, since my property is 'large-ish' (3 bedroomed terrace,
with additional 2 bedrooms in loft, 1 bathroom) - i'm worried if a
combi can cope with it. I certainly dont want cold rooms in the loft!
Price wise, i reckon i can get the boiler for around £600 and get it
installed for another £600-ish. This compares favourably with option
1) above.

Do i go for a high output 30HE condensing boiler, since this seems to
be more powerful than other 24HE boilers, or will a standard
non-condensing combi do the job?

I think the Boiler Choice FAQ may help you, see Below.
Almost certainly the worst thing you can do is to replace the existing
back boiler with an updated model. Such units are expensive and not very
efficient. You probably could get a condensing boiler exception for this
location but you should still think it worth upgrading.

The £600 might be a price for exchanging a combi boiler with another one
of a similar type in a similar location. Converting from the exitsing back
boiler will likely cost a bit more.

--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html
Choosing a Boiler FAQ http://www.makewrite.demon.co.uk/BoilerChoice.html

On 3 Feb 2006 06:48:39 -0800, "Nis" wrote:

Hi folks,

I am thinking of changing my ancient back boiler heating system
(gravity based, pumped). The reason is to get instant hot water, reduce
bills and stop the hassle of pilot lights going out or wasting gas etc.


The options that i have include
1) Converting to a fully pumped system. I asked one guy about likely
costs and he quoted me 'thousands'. Also, a fully pumped system won't
get me instant hot water although the new boiler would probably save
money on gas bills.

2) Just bin the old back boiler and invest in a combi (or condensing
combi). However, since my property is 'large-ish' (3 bedroomed terrace,
with additional 2 bedrooms in loft, 1 bathroom) - i'm worried if a
combi can cope with it. I certainly dont want cold rooms in the loft!
Price wise, i reckon i can get the boiler for around £600 and get it
installed for another £600-ish. This compares favourably with option
1) above.

Do i go for a high output 30HE condensing boiler, since this seems to
be more powerful than other 24HE boilers, or will a standard
non-condensing combi do the job?

Without knowing the heat loss from your house I can't be 100% sure,
but normally a suitable combi would have no problem heating a house
your size. The power output of the boiler is more a limiting factor
for hot water not heating.

A sealed heating system would mean you could lose your loft heating
header tank and with a combi boiler you could lose the cylinder, which
could save some space.

If you need quick filling baths however a combi boiler may disapoint.

To meet building regs most new boilers need to be condensing but you
may be exempt.

Mark

In an earlier contribution to this discussion,
Nis wrote:


Do i go for a high output 30HE condensing boiler, since this seems to
be more powerful than other 24HE boilers, or will a standard
non-condensing combi do the job?

Combi boilers are usually sized according to what rate of 'instant' hot
water production you want to achieve. If you go for one powerful enough to
fill a bath - when timed with a stopwatch rather than a callendar - it won't
have any trouble with the space heating.

Note that you may need to upgrade your gas supply pipes. Also note that a
combi is only viable if you have good mains water pressure and flow. Measure
the rate of cold flow at your kitchen tap with a bucket and stopwatch. If
it's less than 20 litres/minute, you're going to be struggling.
--
Cheers,
Roger
______
Please reply to newsgroup.
Reply address IS valid, but is disposable in the event of excessive
spam.

Nis wrote:

I am thinking of changing my ancient back boiler heating system
(gravity based, pumped). The reason is to get instant hot water, reduce
bills and stop the hassle of pilot lights going out or wasting gas etc.

Yup, I agree with what Ed, Roger, and Mark have said. I would add also
don't underestimate the improvement you can have with a well designed
storage system. A good fast recovery cylinder and well designed controls
on the boiler should see you being able to draw off another bath within
ten minutes or so recovery time.

If you do decide to go the combi route, also bear in mind that it can
also be used to heat stored water. So you can have the advantages of
both if you require - massive flow rates to the baths from the storage
system, and mains pressure instant hot water to showers etc.

If you want acceptable "instant" hot water performance from a combi I
would suggest 35kW as the minimum power output to go for.


--
Cheers,

John.

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On 3 Feb 2006 06:48:39 -0800 someone who may be "Nis"
wrote this:-

I am thinking of changing my ancient back boiler heating system
(gravity based, pumped).

[snip]

The options that i have include
1) Converting to a fully pumped system. I asked one guy about likely
costs and he quoted me 'thousands'. Also, a fully pumped system won't
get me instant hot water although the new boiler would probably save
money on gas bills.

A new boiler and fully pumped system will not get you "instant" hot
water. However, if you have a properly insulated hot water cylinder
then hot water will always be available, unless the cylinder is
emptied of it. With a high recovery cylinder getting enough hot
water for a sink will only take say 10 minutes anyway.

2) Just bin the old back boiler and invest in a combi (or condensing
combi). However, since my property is 'large-ish' (3 bedroomed terrace,
with additional 2 bedrooms in loft, 1 bathroom) - i'm worried if a
combi can cope with it. I certainly dont want cold rooms in the loft!

A properly selected combination boiler will have no problem heating
all the rooms. The question is over hot water. How many people are
normally in the house? Do any of the bedrooms have basins/showers in
them? Do you plan more bathrooms or washing facilities in the
bedrooms? In a large household with lots of hot water use
combination boilers are often not the best option.

ps the best way of saving gas is to insulate the walls and loft, if
that has not been already done.


--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54