I looked at a property today which I'm thinking of buying, and was
very curious about its central heating system, since it has a back
boiler. I know nothing about these things and would welcome the
group's views/advice. I think it probably works; owner wasn't there
and surpisingly (?!) the agent didn't have a clue.
I thought back-boilers derived from my granny's days, when you had an
open fire going all day, and tapped off heat from that to provide HW
and central heating. However, this house is 1970's built; has a
monstrosity of a gas fire in the living room fireplace behind which,
we're told, is this gas boiler. One of those ubiquitous 2-channel
clockwork Danross timers sits by the mantlepiece, so sounds plausible!
Upstairs there's a normal airing cupboard featuring a regular copper
So what's the deal with these gadgets? Will it need replacing? Does
it only work when the living room gas fire is on or something? (surely
not!) If not why bury it behind the fireplace?
They are basically just an open-flued gas boiler that happens to be fitted
into the back of a gas fire. They operate independently of each other, so
you don't have to have the gas fire on to use the central heating (and
There's no reason why it will necessarily have to be replaced if it works
ok, but its probably advisable to have it serviced - like any open flued gas
appliance a blocked flu will mean fumes coming out into the room. They also
need a good supply of air so you may have an airbrick in the room which must
be free from obstructions.
Being an elderly boiler it may not be very fuel efficient, but will probably
have mechanical simplicity on its side so there's not much to go wrong with
I remember some friends of ours had a Baxi back boiler which were all the
rage in their new house in the 70s.
The boiler had a good reputation and worked well but I was slightly bothered
by the fact that you could sit in their lounge with the gas fire off yet
still hear gas being burned by the boiler behind the gas fire. When I hear
gas being burned but can see no flame then I imagine I am about to be
overcome by some ghastly fumes. I also did not reckon it would be easy to
service as it was all tucked away.
It will be a normal fireplace - (I'm pretty sure, but wouldn't swear to it
in blood), which is why the firefront is so protuberant.
Baxi now do a slim profile boiler that will accommodate a fire that looks
built in, or a normal firefront only.
Baxi only started making separate boilers and firefronts in the (guessing)
mid seventies, check the model with them; the later ones allow a new front
or boiler to be installed without affecting the other
Mum and dad have a Baxi back boiler system in their 1966(ish) built
house. Of course it may have been a retrofit since I know for a fact
that central heating was an "optional extra" in these houses, but we
moved in in early 1973 and it was definitely there then, though the
upstairs radiators were only added three or four years ago. In the 1980s
it had a new fire front and a new burner in the boiler IIRC, but little
The programmer has never worked, and now that I'm moving back down (will
be about 1 mile from them) that's something I may play with, though a
lot of others on the estate seem to have ditched the things and
installed fanned-flue boilers in kitchens, bathrooms, lofts and so on.
The house we're taking on also has a back boiler and our surveyor
reckons it is gravity circulated... hmmm... the radiators are new, but
the similarly new tank is in a cupboard in the main bedroom (almost
directly above the boiler) and with insulation is too big to let the
door shut! Methinks that when finances allow something will have to be
done about that.
Martin Angove: http://www.tridwr.demon.co.uk /
Don't fight technology, live with it: http://www.livtech.co.uk /
"John Chapman" wrote
| I also did not reckon it would be easy to service as it was all
| tucked away.
The outer front is only held on to the wall with a couple of screws and
lifts off, then the fire lifts off, and then you're left with a lump of cast
iron with a flamey thing underneath, which constitutes the boiler. Well,
How old is the house? If it was also built in the 70's it may well
have been built without a proper fire place just a hole and flue for
the back boiler.
Having said that the boiler takes up so much space that there isn't
going to be any grate left anyway even if one was orginally there.
I take it you are thinking of removing this gas fire/back boiler and
putting a real fireplace in the space? You probably stand more chance
of getting a grate back in if there was one orginally but I wouldn't
rule it out if not. The flue would need checking for suitabilty as
Dave. pam is missing e-mail
You'rre right, but the modern back boilers can save space, I don't know
where in my hovel I'd put another type - maybe in the loft.
They are nowadays fully pumped, and I've found them very reliable (for more
than 30 years)
Servicing is usually just cleaning, and they are not all that bad, the
firefont and back burner can usually be extricated, and they are simple.
IMO the worst feature is hearing them, especially if they're short cycling,
but I've reduced the power on mine and it's now nearly inaudible
Whilst disagreeing with the actual figure of 40% (more like 30% as the
best saving in IME). Gas used is the recipriocal of efficiency. A really
poor boiler might have an efficiency of only 50% and the best condensing
might be 85%. So the old boiler would need 200 units of gas to do what
the new one can do with 118.
200-118/ 200 approx 41% reduction in gas consumption.
Ed Sirett - Property maintainer and registered gas fitter.
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