Hi,

I currently have a two bedroom house that has a central heating system and
seperate immersion heater for the hot water. The central heating system is
rubbish, it eats gas and the radiators barely get hot, and some of them
hardly warm up at all. Recently the pump has started making a noise too,
sounds like a cavitaing noise, or it could simply be on its last legs. The
pump is under the fitted kitchen, which is not good....

The CH system runs through the immersion heater, and is supposed to heat the
water in there up - I guess that if it was working properly it might do, but
at the moment it just warms the water enough to have a wash in.

I don't know whether to get rid of the lot and have a combi boiler fitted or
replace the existing boiler and pump in the hope that it would heat the hot
water in the immersion tank enough. I am tempted to maybe go for the latter,
but the downside to this being that when the CH is switched off in the
summer I won't have any hot water.

The other thing is, I have recently been asking around for prices on a combi
fitted and have been appalled to the point of disgusted at the prices that
the plumbers charge, I know that they make a lot of money, but the prices
have been ridiculous. If anyone could PLEASE recommend me a reasonable
plumber/heating engineer in the West Yorkshire area I would be eternally
grateful.

Any plumbers in this area reading this please feel free to contact me on
07867 775131

Jay

In article ,
"Wolf Blass" writes:
Hi,

I currently have a two bedroom house that has a central heating system and
seperate immersion heater for the hot water. The central heating system is
rubbish, it eats gas and the radiators barely get hot, and some of them
hardly warm up at all. Recently the pump has started making a noise too,
sounds like a cavitaing noise, or it could simply be on its last legs. The
pump is under the fitted kitchen, which is not good....

The CH system runs through the immersion heater, and is supposed to heat the
water in there up - I guess that if it was working properly it might do, but
at the moment it just warms the water enough to have a wash in.

I don't know whether to get rid of the lot and have a combi boiler fitted or
replace the existing boiler and pump in the hope that it would heat the hot
water in the immersion tank enough. I am tempted to maybe go for the latter,
but the downside to this being that when the CH is switched off in the
summer I won't have any hot water.

Well, you could start by having someone investigate what's wrong
with your current system. It could be something quite trivial.
It would have been interesting if you said what model/age your
boiler is -- might have got some hints on replacement verses
repair. The problem may not be in the boiler anyway, in which
case just replacing it won't fix the problem either.

BTW, central heating boilers are quite capable of heating a hot
water cylinder without also heating the house (unless wrongly
plumbed or faulty).

--
Andrew Gabriel

Thanks for this info - the boiler is a Glow-Worm Space-saver Balanced Flue
Boiler. It looks
quite old and looked old when I moved in here 10 years ago. I havent been
able to afford to
do anything with it until now.

Inside it says:
Nominal Heat Input 54,000/67,000 BTU/h
Nominal Heat Output 40,000/50,000 BTU/h

You mention that CH boilers are capable of heating the h/w cylinder without
heating the house,
I am not sure whether this one will, how can I tell?



Well, you could start by having someone investigate what's wrong
with your current system. It could be something quite trivial.
It would have been interesting if you said what model/age your
boiler is -- might have got some hints on replacement verses
repair. The problem may not be in the boiler anyway, in which
case just replacing it won't fix the problem either.

BTW, central heating boilers are quite capable of heating a hot
water cylinder without also heating the house (unless wrongly
plumbed or faulty).

--
Andrew Gabriel

In article ,
"Wolf Blass" writes:
Thanks for this info - the boiler is a Glow-Worm Space-saver Balanced Flue
Boiler. It looks
quite old and looked old when I moved in here 10 years ago. I havent been
able to afford to
do anything with it until now.

Inside it says:
Nominal Heat Input 54,000/67,000 BTU/h
Nominal Heat Output 40,000/50,000 BTU/h

You mention that CH boilers are capable of heating the h/w cylinder without
heating the house,
I am not sure whether this one will, how can I tell?

Get a CORGI engineer to come along and check it -- I presume you
haven't had it serviced for 10 years, and that alone might be
what's wrong with it. Unless the engineer thinks it's beyond
economic repair, get the engineer to service it and explain the
controls (timeswitch, thermostats, heating/hot water control)
to you. It might be that it would benefit from having more
modern controls fitted.

--
Andrew Gabriel

On Mon, 28 Nov 2005 08:48:58 GMT, "Wolf Blass"
wrote:

Thanks for this info - the boiler is a Glow-Worm Space-saver Balanced Flue
Boiler. It looks
quite old and looked old when I moved in here 10 years ago. I havent been
able to afford to
do anything with it until now.

Inside it says:
Nominal Heat Input 54,000/67,000 BTU/h
Nominal Heat Output 40,000/50,000 BTU/h

You mention that CH boilers are capable of heating the h/w cylinder without
heating the house,
I am not sure whether this one will, how can I tell?



I used to have one of these in a previous house and yes it is. These
are around 20 years old and were never a quality product in the first
place.

Some types of boiler have four pipes, with two (usually larger) going
to the HW cylinder and two for the heating. The HW circuit works by
convection (commonly known as "gravity") - i.e. it naturally
circulates by water heated by the boiler rising and on being cooled by
the cold water in the cylinder, falling. This tends to heat the water
quite slowly.
The heating circuit runs from a second pair of pipes and has a pump to
circulate the water.

The second arrangement is known as fully pumped and has a single pair
of pipes from the boiler. I am pretty sure that this is what you
will have. There should be a diverter valve somewhere or other
(typically in the cupboard where the HW cylinder is), and the pump
will circulate the boiler water to either the cylinder, the radiators
or sometimes both in some designs

The valve should be something like this

http://www.screwfix.com/app/sfd/cat/...70077&id=30424

Note that in almost all cases, the water in the boiler circuit
(primary) is kept separate from the hot water that you use by there
being a coil in the hot water cylinder. There is a cylinder type
called a Primatic, where the CH is filled from the HW side, but these
are unusual. If you go into your loft, and you have a large and a
small tank, you don't have one of these.

Given that nothing has been done to this system for ten years, and
possibly the ten years before that, it is quite likely that it is full
of sludge as a result of corrosion of the radiators. It is also
possible that the diverter valve (assuming there is one) is stuck and
not operating. This can be the explanation of poor performance.
Typically when sludged, the radiators will remain cold at the bottom.

It may be possible to rescue the radiators by having the system
thoroughly cleaned. This can be done as a DIY job by draining and
flushing the system at each radiator, or by renting a power flushing
machine. Alternatively, if you haven't done plumbing work before,
getting a reputable heating engineer would be a better bet. Beware
here. There are outfits who specialise in this work and are rippers
off par excellence. £500+ for a clean is not unusual. British Gas
are cream of the cake with prices around £800 not being unknown.

The boiler might still be servicable. The cylinder could be OK, but
won't be high performance. If you are in a hard water area, it is
probably scaled up and not performing well.

Given the age of everything and lack of maintenance, it may well prove
more economic to take everything out and fit new things. You may need
new radiators anyway if there are signs of any leaks from pin holes
etc.

Then the choices are replacement with a similar system (new boiler and
cylinder) or going for a combi boiler.

If the size of the existing boiler suggests that you have a one bath
or one bath and a shower not used together household, then a mid range
combi of 15 litres/minute HW rate may be enough for your needs. There
are larger models available for if you use bath and shower
concurrently, but these are usually physically quite a bit larger, so
if you have a space constraint you may have to site somewhere else.
Also, before going for a combi, do check the cold mains supply rate.
Using a container of known size, time how long it takes to fill at the
kitchen cold tap. If the flow rate is less than about 20 litres/min,
a combi will be disappointing. Keep in mind also, that even a 15lpm
one will normally take longer to fill the bath than your present
system.

This gives a rough idea of the issues. You really need to invite some
heating engineers along to quote for fixing/replacing as appropriate.



--

..andy

On Mon, 28 Nov 2005 08:48:58 GMT, "Wolf Blass"
wrote:

Thanks for this info - the boiler is a Glow-Worm Space-saver Balanced Flue
Boiler. It looks
quite old and looked old when I moved in here 10 years ago. I havent been
able to afford to
do anything with it until now.

Inside it says:
Nominal Heat Input 54,000/67,000 BTU/h
Nominal Heat Output 40,000/50,000 BTU/h

You mention that CH boilers are capable of heating the h/w cylinder without
heating the house,
I am not sure whether this one will, how can I tell?


I am using exactly the same boiler in my 3-bed semi and it works fine
with separate water and CH as per normal installation.

Indeed they are an old model now and I have an eye on replacing it in
the foreseeable future but providing it is suitable maintained there
is absolutely no reason why it should not do all you require.

It could simply be the pump or a clogged up system I guess. I agree
the danger with some plumbers ( BG included ) is that they wil
condemn it on sight. Best rely on the personal recommendation fo a
friend or colleague.

Andy

In an earlier contribution to this discussion,
Wolf Blass wrote:

Hi,

I currently have a two bedroom house that has a central heating
system and seperate immersion heater for the hot water. The central
heating system is rubbish, it eats gas and the radiators barely get
hot, and some of them hardly warm up at all. Recently the pump has
started making a noise too, sounds like a cavitaing noise, or it
could simply be on its last legs. The pump is under the fitted
kitchen, which is not good....

The CH system runs through the immersion heater, and is supposed to
heat the water in there up - I guess that if it was working properly
it might do, but at the moment it just warms the water enough to have
a wash in.

I don't know whether to get rid of the lot and have a combi boiler
fitted or replace the existing boiler and pump in the hope that it
would heat the hot water in the immersion tank enough. I am tempted
to maybe go for the latter, but the downside to this being that when
the CH is switched off in the summer I won't have any hot water.

The other thing is, I have recently been asking around for prices on
a combi fitted and have been appalled to the point of disgusted at
the prices that the plumbers charge, I know that they make a lot of
money, but the prices have been ridiculous. If anyone could PLEASE
recommend me a reasonable plumber/heating engineer in the West
Yorkshire area I would be eternally grateful.

Any plumbers in this area reading this please feel free to contact me
on 07867 775131

Jay

Andrew Gabriel and Andy Hall have given comprehensive answers on which I
can't improve - but I will add a couple of additional comments.

First on terminolgy - because it helps to use correct descriptions when
discussing things with plumbers. An immersion heater is an electrical
heating element, fitted to a hot water cylinder, to heat the water inside
the cylinder. You may or may not have an immersion heater - but even if you
have, it's not really what we're discussing here. What you have *definitely*
got is an indirect hot cylinder, which has a coil of pipe inside - through
which hot water from the boiler passes in order to heat your domestic hot
water, without actually mixing with it.

When everything is working properly, the water from your boiler heats both
the domestic hot water and the radiators. It is perfectly feasible to heat
*just* the hot water in summer when the radiators are not needed. There
should be settings on your programmer to permit this.

Now for something you may be able to do in the short term to help the
immediate problem. In the attic you should have two tanks - a big one and a
little one. The little one is the so-called fill and expansion tank for the
primary circuit - that's the water which circulates from the boiler through
the radiators and through the heating coil in the hot water cylinder. It is
disctinctly possible that this small tank has run dry - starving the primary
circuit of water, and causing poor circulation/cavitation, etc. It is
supposed to be topped up automatically by a ball valve. But, because the
ball valve only has to operate occasionally, it is quite common for it to
stick shut - and to fail to open even when the water level drops.

So, find the small tank, and make sure that there's a few inches of water in
it - freeing up the ball valve, if necessary. Then bleed all the radiators
and anything else which is bleedable in your system. You may find that
things then improve considerably.

Even if this does make things better, you should still get the system
checked by an expert - and the boiler serviced - as soon as possible.
--
Cheers,
Set Square
______
Please reply to newsgroup. Reply address is invalid.

Wow, thanks for all the useful info guys, I am amazed at how quick and
comprehensively you answered.

I am going to attempt to drain the CH system so I can take a look at various
things such as whether their is sludge in the radiators. I know that there
are two valves at the bottom of the radiators that I can turn off in order
to remove the radiator, but it seems that when I try to undo the big nut
holding the radiator to the valve it twists the valve and loosens the
compression joint underneath it causing leaks, so it might be easier to
drain the whole lot and start from there.

So the question is - how do I drain it? I am presuming that there is some
kind of drain point somewhere, most likely at the lowest point of the
circuit. The pumb is underneath the kitchen floor and this would be the
lowest point, would it be a good place to look? Also - will there be some
kind of connection for a hose or something?

Thanks in advance,

Jay

In an earlier contribution to this discussion,
Wolf Blass wrote:

Wow, thanks for all the useful info guys, I am amazed at how quick and
comprehensively you answered.

I am going to attempt to drain the CH system so I can take a look at
various things such as whether their is sludge in the radiators. I
know that there are two valves at the bottom of the radiators that I
can turn off in order to remove the radiator, but it seems that when
I try to undo the big nut holding the radiator to the valve it twists
the valve and loosens the compression joint underneath it causing
leaks, so it might be easier to drain the whole lot and start from
there.

So the question is - how do I drain it? I am presuming that there is
some kind of drain point somewhere, most likely at the lowest point
of the circuit. The pumb is underneath the kitchen floor and this
would be the lowest point, would it be a good place to look? Also -
will there be some kind of connection for a hose or something?

Thanks in advance,

Jay

I would suggest that you ought to check the F&E tank - and make sure that
there is water in the system - *before* resorting to draining it. That may
be all you need to do in the short term.

With regard to draining radiators, if you remove the plastic knobs or caps
from the valves, you can usually grab the valve body with *light pressure*
from a Mole wrench used from above (so that the end of the spindle
disappears into the jaws) - in order to support it whilst undoing the union
nut, so as not to strain the pipework.

It sounds as if you have wooden suspended floors downstairs - in which case
a lot of the pipework will under the floor. If you're lucky you might find a
drain tap with a discharge pipe going out through an airbrick. That would
enable you to drain the whole system if you really want to - but I don't
think I'd be doing that at this time of year unless absolutely necessary.
--
Cheers,
Set Square
______
Please reply to newsgroup. Reply address is invalid.