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