In an earlier contribution to this discussion,
Christian McArdle wrote:

[So what happens if you have gravity primary circulation in the HW
circuit (with no zone valve and tank stat to convert them to C-Plan
systems) - as a great number of systems still do?]

All such systems and even fully pumped systems without cyldiner
thermostats are indeed dangerous.

Christian.


Agreed, but there are lot of them about - as evidenced by many of the
questions in this NG!

When I had one in my previous house, I at least had a Cytrol valve (a bit
like a TRV) in the gravity return, to stop the flow when the HW was hot
enough. [Only problem was that the flow would occasionally decide to go the
other way round - whereupon the Cyltrol found itself on the *input* side of
the cylinder - and I got no hot water!]
--
Cheers,
Set Square
______
Please reply to newsgroup. Reply address is invalid.