wrote in message
ups.com...
As a result of this thread http://tinyurl.com/8um67 we eventually
replaced the pump with a Grundfos (and wired in a permanent live to
allow pump overrun) 25/55.

We bought it last spring and it was finally fitted around October.
Now, barely a year after being installed, it has failed. Grundfos give
18months warranty from date of manufacture and ours is now outside
that.

This doesnt seem a reasonable life for a pump to me - any advice?

I'm on my second pump in 30 years, with the second pump giving no sign of
impending failure. Having said that the system works on gravity for hot
water (no need for pump to run for this purpose) and we do not use the
central heating system extensively.

Do you have a "clean" system? I would think that the system contaminants
would have a considerable effect upon the life of the pump impellor
bearings. My system was installed with a corrosion inhibitor immediately
after flushing during initial commissioning i.e. it has never run with no
corrosion inhibitor. If no inhibitor is present it will only take a few days
for a considerable amount of corrosion products to be generated and these
will affect the subsequent life of the pump.

Against my advice, my brother installed a mild steel radiator on the circuit
of a non-closed system, it lasted about 6 weeks before it was holed, thus is
the rate of rusting in an un-protected system.

My daughter does have a fully pumped system, which has a pump of unknown
vintage installed, but it has lasted at least four years, with expectations
of further service to come.

In answer to your question, the life of your pump does seem rather short. It
may be that you are just unlucky, or that there is an explanation along the
lines I have suggested to explain it's lack of longevity. On the other hand
it may have been an electrical problem, which do occur unpredictably from
time to time.

Hope this gives you some food for thought

Regards

Pilgarlick