I have a 20 years old Glow-worm Spacesaver wall boiler which works fine,
providing pumped CH and gravity DHW.
B/Gas 3 star engineers keep telling me the they can "no longer guarantee to
be able to source spares"...ie a sales ploy to sell a new boiler.
Our local council are supplying discounted high efficiency boilers as a
greening initiative, but I reckon the bill will be £2k with fitting and
maybe mods to the exisiting system.
Any of you experts got any impartial advice ?
My gut instinct is to try and source spares for my existing boiler to keep
it going as long as possible.
What do you think.?
Keep it going. Start putting money into a replacement fund for when it
finally breaks down terminally. Don't bother with boiler insurance. If you
hadn't paid for it and just put the cash into a bank account, you'd probably
already have saved enough for a new boiler...
I would update the system at a time of *my* choosing, and certainly *not*
employ BG to do it.
It's pretty certainly a sales ploy to try to sell you a new boiler -
although there *may* be a risk of not being able to get spares at some
point, which would leave your stranded. Meanwhile BG still seem willing to
take your money for a maintenance contract - which would be fraud if they
*knew* they couldn't get spares. [There are lots of on-line sources of
boiler spares. It wouldn't do any harm to line up possible sources of PCBs
(if applicable), fans (if applicable), thermostats, gas valves etc.]
Updating your system will cost quite a lot of money. Not only will you need
a new boiler but you will also need to modify the pipework and add a lot of
controls - zone valves, tank stat, TRVs, etc. to comply with the latest
regs. BUT, having done it, you will save a *lot* of fuel. Modern boilers are
much more efficient than 20-year-old models and, coupled with better
controls, you'll achieve the same or better comfort levels with a lot less
So it *is* worth doing - but you can choose your own time to do it.
As an aside, I've just had a conversation with my boiler service guy
(very local -- I know him well, as he lives three doors away), who was
saying that from (April?), new installations will have to use
condensing boilers, and conventional boilers like mine (which is 7 or 8
years old) will no longer be installed.
He understands the efficiency reasoning behind this -- although, as he
noted, placing a condensing boiler on an old system can reduce the
efficiency to the point where it's not actually condensing -- but
mentioned that he's quite busy at the moment installing conventional
boilers for people who want to beat the deadline for the new regs.
AIUI, boilers will have to be capable of at least a certain efficiency
level - which condensing boilers can meet more easily. I'm not sure that
it's necessarily *impossible* to meet with a non-condensing boiler?
*Can* but not necessarily *does*. Systems designed to run at a high radiator
temperature won't allow the boiler the condense when running at that
temperature. But this will only happen in very cold weather. In milder
conditions, the rads can run cooler - but be on more of the time - which
*will* allow the boiler to condense.
That would be interesting to know -- but from my friend's statement it
sounded as if the manufacturers werent' going down that road. (He
mentioned that the only non-condensing boiler which was currently
available without jumping through hoops was a floor-standing rather
than wall-mounted model.)
Yes, right: he was quite clear that it was system-dependent. He was
just making the point that increased efficiency depends on more than
simply hooking up a condensing boiler to all existing systems.
Having said that, a new boiler - condensing or not - is going to be a damn
sight more efficient than a 20-year-old model anyway!
Personally, I wouldn't want it *too* efficient. Stray heat from my boiler is
the *only* heat I curently have in my utility room!
Not so. A 50-55% efficient cast-iron clunker replaced by a high efficiency
condenser with TRVs, and ate-of the art controls, quick recovery cylinder
etc, will give approx 40% (older boilers are nor suited to quick recovery
cylinders as they cause the boiler to condense). Remember the old boilers
efficiency would have tailed off over the years. I have come across this
sort of efficiency hype.
There you are. easy.
A quick look at the SEDBUK database shows over 3000 boilers listed, of
which approx 1% have efficiencies listed at 55%. 99% are 65% or better.
That would suggest achieving your 40% figure is going to be a rare event.
Replace an old boiler with decreased effciency over time, add a new quick
recovery coil cyilinder, modern controls, etc, replaced by a top line boiler
will give 40%. It is the boiler and amendments to the system that all add
And if the old boiler has an efficiency of 75% and already has a decent
control system dIMMs only answer is "snip drivel" because he doesn't
understand the figures. To him 40% is just a magic incantation.
Of course when you think about it, it does not "add up". Your quick
recovery coil cylinder will heat up faster and hence take more power
from the bolier, but the total energy consumption to heat x litres of
water stays the same as with the old cylinder. So the only gain in
efficency there is the boilers, and you can't count that again.
There is a very *marginal* effect - and I doubt whether you could measure
it. If you heat the water faster, the boiler and the intermediate pipework
are hot for less time, so there are *slightly* less losses in this area.
This argument is probably more valid when used in a pumped vs gravity HW
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