"Aidan" wrote in message
oups.com...

IMM wrote:


to close the valve so water from the flow mixes with the
cold slug to keep the temp above 60C.

Close the valve?

If it is a valve, it's generally a 3-port
diverting valve, which doesn't close, it diverts.

Of course it is'nt, it is a 3-way "mixing" valve. It is clear you only have
half a clue how it works.

Also, could be a shunt pump. Both are
intended to stop back-end corrosion,
not thermal shock.

But the 3-way "mixing" valve keeps the temp above 60C into the boilers
return.

Both stop working when Tr60 degC,
which might not prevent thermal shock.
Back end protection is nothing to do with thermal shock.

You can do "both" with a good controller, quick action sensor on the boilers
return, and a 3-way "mixing" valve. It used to design them.



_________________________________________
Usenet Zone Free Binaries Usenet Server
More than 120,000 groups
Unlimited download
http://www.usenetzone.com to open account