"The Night Tripper" wrote in message
o.uk...
Hi Harry

[...]
You don't even mention what fuel you are burning.
Do you mean by back boiler a thing behind an open coal fire?
Or a gas boiler behind a gas fire?

I mean behind a gas fire. does that make it a 'gas boiler'? I wouldn't
have
thought so, but ...


Hardly seems worth the effort. The heat exchanger in your tank may
well be scaled up. I would start by a thorough clean and descale of
your DHW tank(cylinder).
This may well resolve your problem.

This is a fair point - we live in a hard-water area (south Coast) and
there
may be a fair bit of scale. As I say, it's partly a 'yen' ...

And make sure the tank is well insulated.

Yes, it's well insulated, thanks.


If it is behind a gas fire it will run on gas, and work even when the gas
fire is not lit.
This makes it a gas boiler.
Sounds like the Baxi back boiler we had in Berkshire.
Is it, perchance, a Baxi?
How old is the system?
When we had ours replaced (probably installed a long time ago - '60s?) the
plumber drained the CH but had to drain down everything eventually because
the heat exchanger was leaking and kept filling the heating up again from
the hot water header tank.
He needed another person to help remove the hot tank because it was so full
of scale and gunge.

My lady wife sold the tank for scrap to a couple of door knockers and you
could see the trail of scale where they had staggered from our front drive.
I don't know how you clean up such a cyclinder to sell for scrap - just
weigh it in and hope the yard doesn't notice it is paying copper prices for
limescale?

So - unless it is a very recent installation and has also been always
treated with central heating inhibitor products there could be problems on
the heating side.
In a hard water area, unless you use a water softener, there is likely to be
a build up of scale over time in the hot water cylinder.
As advised elsewhere it is a good idea to take out the hot water cylinder
and give it a thorough checking.
If it is gunged up and/or leaking at the heat exchanger you may solve most
or all of your problems by fitting a new more efficient (and possibly
larger) cyclinder.
You may be 'polishing a turd' if you just modify the pipework without
confirming that the hot water tank is functioning correctly.

HTH

Dave R
--
No plan survives contact with the enemy.
[Not even bunny]

Helmuth von Moltke the Elder

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