John wrote:
In article , Triffid
writes
harry wrote:
On Mar 11, 5:55 pm, "Triffid" wrote:
John Rumm wrote:
On 11/03/2011 14:56, harry wrote:
On Mar 11, 9:10 am, wrote:
OK, this changes from time to time I guess.
I may be getting a new combi boiler , about 30kW.
Up to a 1000 quids.
What is the most reliable boiler around at the moment for that
spec ? I.e. one that has the vaguest hope of lasting 10 years (I
know its ridiculous !)
Gas chap recommends Vaillant ...
Cheers,
Simon.

Don't bother with a combi. They are ****e of the devil. Put in a

You seem determined to steal dribble's crown harry.

conventional system ie with roof tanks and the HW storage tank
(well lagged). There's such a thing as too much technology. You
will still have to have a condensing boiler. It will cost you
more but there will be far less trouble and expense with repairs
and spare parts.

Huh?

What is the difference between a system boiler, and a combi?
Answer a small PHE, and a diversion valve and a flow switch.

What do you need to make a system boiler usable with a cylinder?
Zoning valves of some description. So the overall difference in
*system* complexity is approaching nil.

This also means you can install a solar hot water roof panel
which you can't with a combi. Also your bath will fill quickly.

The problem with all these numpty responses of "combi = good all
else evil" and their inverse, is they ignore the real world. There
are plenty of cases where one type of system is going to be vastly
preferable to the other, and to blindly insist on only the one
"allowable" solution demonstrates either ignorance or stupidity.

I agree. It's horses for courses. A condensing combi suits my
household because there is only one bathroom and just the two of
us. If we had an en-suite and wanted to shower at the same time, a
conventional storage system would probably be a better bet.

--
Kev- Hide quoted text -

- Show quoted text -

Combi boilers were made for one purpose only. To fit in new houses.
Cheaper than a conventional system and can be fitted with
semiskilled labour.

Absolutely stupid removing an existing DHW cylinder/header tank(s)
just to put in a combi.

Keep It Stupid Simple is always the way to go. Minimum technology
to achieve requirements.

Well, I hear what you say, but the significant advantage for us was
being able to get rid of the airing cupboard in the bathroom and
replace it with a walk-in shower. Because the new shower has clear
glass doors it has made the bathroom appear much larger as well.

Having instant hot water always on tap is also a bonus.

I agree with the need to keep things simple - and our plumbing
system is now a lot simpler than it was when it had two header tanks
in the loft and a hot water cylinder in the airing cupboard. (I got
£75 scrap for the copper tank and redundant pipework when the job
was done)

There is now no float valves to stick or go wrong in the loft, no
chance of any leaks or bursts in the loft, no motorised valves in
the system to stick or go wrong.

I couldn't believe the amount of gunge there was in the bottom of
the cold water tanks in the loft either!

Lucky you - although the Combi at the Scout Hut provides adequate heat
to the radiators, it fails to give anything other than tepid water out
of the taps event when it is turned up to max and the taps down to the
lowest flow that triggers the boiler.

I was very sceptical about whether I would be happy with a combi because
both my father and my mother-in-law had lived in houses with combis that
behaved exactly as you describe. In my father's bungalow it could take the
best part of an hour to fill his bath!

I think the problem is that replacement boilers are very much a 'distress
purchase' and, consequently, many people go for the cheapest option - a
boiler with the minimum power rating possible for the premises in question.
Also, the early combis were inherently poor anyway.

Combi technology (in particular in relation to the heat exchangers) has
advanced considerably.

If I visit the Worcester Bosch website and complete their 'find a boiler'
questionaire, they recommend the 24 kw Greenstar Junior boiler for my
3-bed/1 bathroom house. In fact I had a 30 kw Greenstar CDi installed. The
greater the power, the higher the flowrate at a given temperature of
course - and we find that the flow and temperature from the taps is more
than adequate. The domestic hot water thermostat on the boiler is set at the
'eco' level which is only about 1/3rd of the way up from minimum - and is
still fine. When the hot tap is running you cannot hold your hand in the
flow - it is too hot.

It's a pity, I think, that many people have been put off buying a combi
because of experiences with older, inadequately powerful, boilers.

--
Triff