"Andy Hall" wrote in message
...
On Wed, 30 Jul 2003 00:17:19 +0100, "IMM" wrote:

If you decide to go the 3 port way - be strongly advised that the
diveter valve variant (either but not both CH and HW) - has been
found
wanting by many.

This new to me. A 3 port diverter is as
simple as a two port. They use the
same heads.

I had diverter valves of this type in my system from when the house
was built until I ripped it out with the rest of the abortionate
plumbing that they had done in the airing cupboard.

There were four replacements over a 15 year period which I don't think
is impressive. Typically, either the mechanism would stick in the
base or a leak would develop.

Sounds like a poor make and compounded by a poorly installed system.
They
can be fitted on the cooler return pipe which enhances longevity.

IIRC, the original was made by Switchmaster? (had a blue motor head),
there were then I think a Danfoss and two Honeywells, with the latter
two lasting about 4 years each. I wouldn't call Danfoss and
Honeywell poor makes as such.

On a far simpler valve you have a failure rate far higher than the more
troublesome mid-position 3 port valve. Sounds like the system was faulty
somewhere.

The fitting position was on the return in one of the recommended
positions so no clue there either.

I even went to the trouble of exercising the heating at least weekly
during the summer months so that the valve wouldn't stick. The
failures weren't at any particular time of year.

Correct and sufficient inhibitor can lubricate valve mechanisms. A two pump
casting Grundfoss Tee setup can be used instead of any 3-port valve,
mid-position or diverter.




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