"Ed Sirett" wrote in message
news
On Sun, 25 Jan 2004 20:15:07 +0000, Andy Hall wrote:
On Sun, 25 Jan 2004 18:40:38 -0000, "David Hearn"
wrote:
Andy Hall wrote:
On Sun, 25 Jan 2004 13:23:39 -0000, "David Hearn"
wrote:
Our hulk of a boiler (Baxi WM 531 RS) is nearing death. The heat
exchanger is leaking and we're finding we're getting a funny smell
now. Couple of months ago we had a different funny smell when I
split the thermostat's capillary tube but after replacement that is
still intact and the boiler is working, unlike before.
I believe the smell to be caused by the evaporation of the water in
the boiler and coming out the hole for the thermostat probe. Not
actually sure of the cause of the weird smell (X100 inhibitor,
Fernox Boiler Silencer or just some sludge) but its related to the
boiler being on, and the flames are burning nice and blue (though
flares up orange sometimes - I suspect when liquid drips into the
flame). When the boiler is turned off for an hour or so, there is
water sitting in the hole for the thermostat probe and rust is
getting worse around it.
Now, firstly, is this smell/gas likely to be dangerous? Obviously
you don't want to be drinking the inhibitor, but what about the
smell from it? We're making sure we ventilate the area well
(because its not a nice smell!).
This needs to be pensioned off pretty quickly........
Plans are underway for a few weeks time.
If its not dangerous, then I have a little more flexibility with
when I replace the boiler (few weeks, maybe month or so rather than
days). Longer is better as I can then fit around my Dad's
availability etc.
My plan is to go for a cheap/cheerful Ideal Classic SE RS boiler.
Current boiler is a 62,000 BTU (18.4kW) input with 44,500 BTU (13kW)
output. I assume that if replacing like for like then I just go for
one with a similar output (therefore the Ideal Classic 15kW version)
rather than looking at the input rating.
As long as you are happy with the heating performance, then match the
outputs as you suggest.
Sedbuk's 'whole house' checker estimates about 10.7kW, so maybe I could
go
for the 12kW version, though the 15kW one is closest to what I've got,
and
that works well enough.
I wouldn't go lower than you have already.
My reasoning for this boiler is that I should be able to use the
same hole in the wall with the current balanced flue for the new one
(or with minimal work). Rather than having to brick it up and put
in a fanned flue (among other things).
It's really no big deal at all to put in a fanned flue. Most of them
are a set of concentric tubes and the size is smaller than for
unfanned units. I did the complete job from having removed the old
boiler to having the hole bricked up and the new flue located in a
couple of hours and I rarely lay bricks......
In our case the wall is rendered (with a Tyrolean finish?) and is quite
old.
I would prefer to have as little rendering to do, matching paint is
another
problem - and no plans on re-painting the house!
In any case, there is no guarantee that the dimensions of a new unit
will put the flue in the same place as an older model, so at least
check that.
Yup - I'm aware of that, though I'm hoping that one balanced flue is
pretty
similar in shape to another. Due to the size of our current boiler
(wide -
width of flue and then another 6 inches) and the shape of new boilers
(narrow - about width of balaced flue) I expect there'll be quite a bit
of
work inside to make good etc. Trouble I have is that there's a hole in
the
ceiling for the plumbing and a hole in the wall for the wiring - both
within
the casing area of our current boiler, but outside of the casing area of
the
new one - so a bit of work will be needed to make it look tidy - though
we
do have some spare 50cm kitchen cupboards which may well allow us to
hide it
away subject to manufacturer guidelines.
Also, I want one which I can install myself (with help from my Dad
who did his boiler a year or so ago) and doesn't require any
specialist gear to set up (ie. flue gas analyser). AFAIK, a simple
boiler like that should just require adjustment to make the pilot
flame a certain size and also to get the required pressure on the
test point.
I know the benefits of condensing boilers - and unless you can
install one without any serious test-gear, I wouldn't consider it.
On many of them you can. It isn't so much an issue of whether the
boiler is condensing or not but rather the age and origin of the
design. Some of the more sophisticated controls require the use
of a flue gas analyser to set up max and min gas rates.
However other boilers are set on burner pressure or on gas rate
measured by reading the meter and timing. You would need a manometer
anyway to do part of the soundness test and they are about £15.
Don't suppose that you know of which boilers don't *require* flue gas
analysers?
In terms of installation, the only additional thing for a condensing
model is to provision the condensate drain and that is trivial.
Considering that you would save 20-25% of energy costs and some quite
inexpensive condensing models can be found, to me it seems a
no-brainer to use one, even accounting for all your other expenditures
and reduced income.
But I'll already be saving fuel costs by using a new boiler compared to
a
15/20 year old one - I wouldn't get 20-25% extra by going with
condensing
over standard.
The Ideal Classic SE RS has a SEDBUK efficiency of 79.9% which is low
compared to 91% for the better condensing boilers. Some condensing ones
go
as low as 85-86%. SEDBUK claim that large old heavy weight boilers
(which I
would say the Baxi WM 531 RS we currently have is) is only 55%
efficient.
Even if it was a lightweight one it would be only 65%. Currently we pay
about £30 a month for gas I think, £360 a year (which is between
SEDBUK's
heavy and light weight estimates for a semi).
Assuming currently 65%, then if we went to 100% efficiency, we'd spend
£234
a year (£126 pa saving). 90% efficiency would cost £260 (£100 pa
saving),
85% cost £275 (£85 pa saving) and 80% efficiency £292 (£68 pa saving).
So, going with a condensing boiler I would save between £85 and £100 per
yead and with the Ideal Classic I save just £68. The savings over the
Ideal
Classic would be about £17 to £32 a year.
Ideal Classic SE 15kW £582 inc VAT.
Ideal Icos HE 15kW £675 inc VAT.
Are you sure that the vanilla SE is still available? I can only find
price references for the fan flue version and I believe you have to
add a flue kit for that.
Additional cost of condensing, £93. Best case it would take 3 years to
pay
for itself, worst case 5 years. Might be worth a look depending on
cost,
and how long we expect to live here.
Something I did fail to mention is that the system is currently vented -
and
I don't want to convert it to a sealed system (work, plus chance of
leaks -
at least 1 part weeps currently).
I was going to raise that point.
So - can anyone suggest (and recommend!) a condensing boiler that meets
the
following requirements:
Suitable for vented/unsealed system (and not a system boiler).
Definitely does not require a flue gas analyser for
installation/comissioning - just pressure checks.
Does not cost more than £700 including VAT/delivery (any more is too
expensive/too long to recoup additional cost).
Reasonably easy installation.
Not quite at your budget, but it might be comparable once all the bits
are accounted for, would be the Keston Celsius 25. Discounted
Heating have this for £797 inc.
I considered this one for my installation the year before last so
researched it thoroughly. Ed Sirett and Andrew Gabriel have this
one and as far as I know are pleased. Tont Bryer fitted two in his
church.
It is a system model, in the sense that the pump is integral, but that
is a good thing because the pump is switched between settings
according to heat output which matches flow, temperature drop and
output more effectively. Using this is trivial, because you simply
take the old pump out of circuit.
The flue design is good and uses high temperature 50mm plastic waste
pipe which can be obtained from plumbers merchants very cheaply. You
can run long lengths of flue if it helps or just straight out. The
boiler comes with the flue terminal bits so no extra cost there.
This is a pretty compact boiler and does not require a flue gas
analyser for setting - there is a check by timing the meter.
It will run with sealed or vented circuits.
Power output modulates from 7 - 25kW so matches your needs
comfortably. One other benefit out of this is that it may heat the
hot water a little more quickly. If you replace the cylinder at some
point with a new one, you can use a fast recovery type and it will
heat very quickly and have the power available to do so.
I have to be able to
do myself as a number of large, unbudgeted costs have come along
(like replacing 2 rotten bay windows which are causing the bay to
drop - approx £4k) just as a baby is due and we go to one income.
I'm not going to put our family in any danger by doing it myself -
but also we cannot afford to pay someone £1.5k (minimum total cost
for someone to supply/install it I've had suggested) when we can
just about afford £600 for the boiler.
So - what do people think about the Ideal Classic SE RS series
boiler? Reasonably reliable? Easy/straightforward to install?
It'll just be a simple replacement of a pumped (S plan I think)
system running off an old balanced flue boiler to another balanced
flue boiler. Controls are up to date - programmable room
thermostat, 2 channel programmer, boiler stat, 2 zone valves, TRVs,
pump etc.
One final question - what is the "standard flue pack" that is
separate to the boiler? Is this the balanced flue to go with it or
is that something different? I realise there is a Fanned Flue
version - but we're not after that - just the plain Balanced Flue.
I'd be tempted to fit a fanned flue boiler of a non-condensing type,
the old balanced flue boilers are generally much less efficient than a
fanned model.
Most new boilers you can get the instructions for online so you can check
out
where the flue and mounting points would come.
Don't go below 15kW since you need to have some HW capacity and you might
replace the cylinder with something faster during the life of the new
boiler.
Most boilers are sold with a 'standard flue kit' which will usually let
you mount the boiler on or adjacent to an outside wall.
I believe that you can still get balanced flue boilers but other than for
the cheapest and quickest like for like replacement I can't think why
anyone would want one.
A boiler like the Potterton Profile 50eL would also be good if the price
was not too high.
If you could fix the leaks then I'd strongly recommend you go for a sealed
system in which case
A Vaillant Thermocompact 615e or a Glow Worm Compact 60 would be on the
shortlist.
If you go for a condensing model then the Keston Celsius 25 would be a
good choice.
I recently fitted a new combi on my own, a Vaillant Turbomax, and this
did
not require a flue gas analyser, so I presume neither would the
Thermocompact
boiler. The job was lengthy ( especially so since I resited the boiler from
an
upstairs bedroom to an outside toilet ), but within the scope of a competent
DIYer with a bit of common sense and technical aptitude, so a straight
replacement
of a boiler in the same position should be within your capabilities. The
Vaillant
Turbomax comes with all gas settings factory preset, so unless you're keen
to "tune" your gas boiler to your particular system requirements, no
adjustments
are needed ( I presume all Vaillants are like this )
I found the only "special" tool needed was a u-tube manometer, but
you can
make one yoursely with clear plastic tube, a ruler and a bit of wood if
you're hard-up.
The only vaguely hairy work is the gas side of things, but Ed Sirrett has
written an
excellent FAQ on leak-testing etc. Do the ground-work first and down-load
the
boiler and flue installation pdf files for your chosen boiler before you buy
so
you know what you need to do. Vaillant certainly has these available on its
website,
some other manufacturers do too. If you do the gas side of things your
guarantee may not be valid, so buy a decent make, and also bear in mind that
a
boiler fault that causes damage may not be covered on your insurance ( so
make
sure you do it right! )
Andy.