Hi all, just recently the central heating in our house stopped working.
It would appear that the pump is acting up, as the boiler (Glowworm
Ultimate 50BF) still heats the hot water, and the room temperature
thermostat still 'clicks' when it is turned. The pump, however was red
hot to the touch. One of my neighbours is a young chap who works for
British Gas, so he came in to have a look. By this time, I had turned
the boiler off and the thermostat down, and the pump had cooled down too.
When he came in, he gave the pump a clout with a rubber mallet, and
turned up the flow rate to max (I couldn't see this, as it was on the
reverse side of the pump). Lo and behold, the heating started working
again. However, the other night there was a horrible smell of burning
electrical components, so I turned everything off.
The pump is a Commander 'S' SMC, and the neighbour reckons it's about 25
years old. The problem is, apparently the size of the bore. He brought
around a new pump to replace the old one, but the bore on the old one is
about 1", whereas the new one is probably metric 12mm or similar.
Question is - is it possible to get either a new pump with the old size
bore, or could I get reducers to change to the new pump's bore? Needless
to say, the pump is in an awkward position, and would mean the removal
of kitchen cupboards to replace it.The old pump has a valve on either
side, by the way.
Any help, thoughts etc. greatly appreciated!
Regards
John

On Tue, 22 Mar 2005 12:23:12 +0000, John Orrett wrote:

Hi all, just recently the central heating in our house stopped working.
It would appear that the pump is acting up, as the boiler (Glowworm
Ultimate 50BF) still heats the hot water, and the room temperature
thermostat still 'clicks' when it is turned. The pump, however was red
hot to the touch. One of my neighbours is a young chap who works for
British Gas, so he came in to have a look. By this time, I had turned
the boiler off and the thermostat down, and the pump had cooled down too.
When he came in, he gave the pump a clout with a rubber mallet, and
turned up the flow rate to max (I couldn't see this, as it was on the
reverse side of the pump). Lo and behold, the heating started working
again. However, the other night there was a horrible smell of burning
electrical components, so I turned everything off.
The pump is a Commander 'S' SMC, and the neighbour reckons it's about 25
years old. The problem is, apparently the size of the bore. He brought
around a new pump to replace the old one, but the bore on the old one is
about 1", whereas the new one is probably metric 12mm or similar.
Question is - is it possible to get either a new pump with the old size
bore, or could I get reducers to change to the new pump's bore? Needless
to say, the pump is in an awkward position, and would mean the removal
of kitchen cupboards to replace it.The old pump has a valve on either
side, by the way.
Any help, thoughts etc. greatly appreciated!
Regards
John

Based on the boiler model, you would have a typical sized house.
So you need a 'normal' pump so a '5metre' unit will do but '6m' won't be
wrong. Usually pumps are 130mm between flanges on the couplings, some
larger and/or older pumps may not conform to that.
Forget all about the 'bore' the pump has to join to 22mm pipe work (very
likely assumption). If the existing couplings won't hack it then the
system will have to be drained and new couplings used.






--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html

Ed Sirett wrote:
On Tue, 22 Mar 2005 12:23:12 +0000, John Orrett wrote:


Hi all, just recently the central heating in our house stopped working.
It would appear that the pump is acting up, as the boiler (Glowworm
Ultimate 50BF) still heats the hot water, and the room temperature
thermostat still 'clicks' when it is turned. The pump, however was red
hot to the touch. One of my neighbours is a young chap who works for
British Gas, so he came in to have a look. By this time, I had turned
the boiler off and the thermostat down, and the pump had cooled down too.
When he came in, he gave the pump a clout with a rubber mallet, and
turned up the flow rate to max (I couldn't see this, as it was on the
reverse side of the pump). Lo and behold, the heating started working
again. However, the other night there was a horrible smell of burning
electrical components, so I turned everything off.
The pump is a Commander 'S' SMC, and the neighbour reckons it's about 25
years old. The problem is, apparently the size of the bore. He brought
around a new pump to replace the old one, but the bore on the old one is
about 1", whereas the new one is probably metric 12mm or similar.
Question is - is it possible to get either a new pump with the old size
bore, or could I get reducers to change to the new pump's bore? Needless
to say, the pump is in an awkward position, and would mean the removal
of kitchen cupboards to replace it.The old pump has a valve on either
side, by the way.
Any help, thoughts etc. greatly appreciated!
Regards
John


Based on the boiler model, you would have a typical sized house.
So you need a 'normal' pump so a '5metre' unit will do but '6m' won't be
wrong. Usually pumps are 130mm between flanges on the couplings, some
larger and/or older pumps may not conform to that.
Forget all about the 'bore' the pump has to join to 22mm pipe work (very
likely assumption). If the existing couplings won't hack it then the
system will have to be drained and new couplings used.

Thanks for the reply Ed; yes, we are in a 3 bed semi! So it theoreticaly
should be a case of drain the system, take old pump out, fit reducers at
either end, and then install new pump (presumably having to cut off a
bit of pipe either side to allow the reducers?). I assume that reducers
from 22mm to 12 mm (ish) are available?
Regards
John

In an earlier contribution to this discussion,
John Orrett wrote:


Thanks for the reply Ed; yes, we are in a 3 bed semi! So it
theoreticaly should be a case of drain the system, take old pump out,
fit reducers at either end, and then install new pump (presumably
having to cut off a bit of pipe either side to allow the reducers?).
I assume that reducers from 22mm to 12 mm (ish) are available?
Regards
John

I don't understand your problem! I don't know what sort of pump you saw with
12mm connections - but it was unlikely to be a central heating pump!

AFAIK, virtually all CH pumps have flange connections with a 1.5" BSP
thread. [See
http://www.screwfix.com/app/sfd/sea/...&cd=1&x=8&y=13
as an example].

You then have a valve similar to
http://www.screwfix.com/app/sfd/sea/...cd=1&x=10&y=10
on either side of the pump - which screws onto the threaded flange and
connects to the 22mm pipework.

You can normally close the valves to retain the water in the system, unscrew
the valves from the pump and insert a replacement pump - all without
draining down. The only provisos are (a) that the valves work and (b) that
the replacement pump is the same physical size in respect of distance
between flanges.
--
Cheers,
Set Square
______
Please reply to newsgroup. Reply address is invalid.

Set Square wrote:
In an earlier contribution to this discussion,
John Orrett wrote:


Thanks for the reply Ed; yes, we are in a 3 bed semi! So it
theoreticaly should be a case of drain the system, take old pump out,
fit reducers at either end, and then install new pump (presumably
having to cut off a bit of pipe either side to allow the reducers?).
I assume that reducers from 22mm to 12 mm (ish) are available?
Regards
John


I don't understand your problem! I don't know what sort of pump you saw with
12mm connections - but it was unlikely to be a central heating pump!

AFAIK, virtually all CH pumps have flange connections with a 1.5" BSP
thread. [See
http://www.screwfix.com/app/sfd/sea/...&cd=1&x=8&y=13
as an example].

You then have a valve similar to
http://www.screwfix.com/app/sfd/sea/...cd=1&x=10&y=10
on either side of the pump - which screws onto the threaded flange and
connects to the 22mm pipework.

You can normally close the valves to retain the water in the system, unscrew
the valves from the pump and insert a replacement pump - all without
draining down. The only provisos are (a) that the valves work and (b) that
the replacement pump is the same physical size in respect of distance
between flanges.

Hi Set Square - I see where you are coming from!Thanks for the links,
that made things much clearer. I didn't realise that the pump valve gate
was a separate unit. I thought it was an integral part of the pump. So
presumably it should just be a case of close both valves, turn off the
electrics ,unscrew the pump from the pump valve gates and remove the
wiring, and then reinstall? I'll put a bit of WD40 on the valves in the
meantime. I'll check the distance between flanges also!
Thanks again,
John

John Orrett wrote:
Set Square wrote:

Hi Set Square - I see where you are coming from!Thanks for the links,

that made things much clearer. I didn't realise that the pump valve
gate
was a separate unit. I thought it was an integral part of the pump.
So
presumably it should just be a case of close both valves, turn off
the
electrics ,unscrew the pump from the pump valve gates and remove the
wiring, and then reinstall? I'll put a bit of WD40 on the valves in
the
meantime. I'll check the distance between flanges also!
Thanks again,
John

Just in my experience those gate valves never fully close off the
supply so have lots of towels around and act quickly!

On Wed, 23 Mar 2005 10:43:25 +0000, John Orrett wrote:

Set Square wrote:
In an earlier contribution to this discussion,
John Orrett wrote:


Thanks for the reply Ed; yes, we are in a 3 bed semi! So it
theoreticaly should be a case of drain the system, take old pump out,
fit reducers at either end, and then install new pump (presumably
having to cut off a bit of pipe either side to allow the reducers?).
I assume that reducers from 22mm to 12 mm (ish) are available?
Regards
John


I don't understand your problem! I don't know what sort of pump you saw with
12mm connections - but it was unlikely to be a central heating pump!

AFAIK, virtually all CH pumps have flange connections with a 1.5" BSP
thread. [See
http://www.screwfix.com/app/sfd/sea/...&cd=1&x=8&y=13
as an example].

You then have a valve similar to
http://www.screwfix.com/app/sfd/sea/...cd=1&x=10&y=10
on either side of the pump - which screws onto the threaded flange and
connects to the 22mm pipework.

You can normally close the valves to retain the water in the system, unscrew
the valves from the pump and insert a replacement pump - all without
draining down. The only provisos are (a) that the valves work and (b) that
the replacement pump is the same physical size in respect of distance
between flanges.

Hi Set Square - I see where you are coming from!Thanks for the links,
that made things much clearer. I didn't realise that the pump valve gate
was a separate unit. I thought it was an integral part of the pump. So
presumably it should just be a case of close both valves, turn off the
electrics ,unscrew the pump from the pump valve gates and remove the
wiring, and then reinstall? I'll put a bit of WD40 on the valves in the
meantime. I'll check the distance between flanges also!
Thanks again,

That's the theory. I practice with kit that's been around for 25 years you
_will_ end up draining the system and fitting new couplings and pump.

The rubber washers between the pump and coupling flanges will have been
turned to charcoal over the time, but new ones come with the new pump.

HTH


--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html