In an earlier contribution to this discussion,
Christian McArdle wrote:
In any case, there is no indication that the F&E tank pipework passes
through this location, or that the system is gravity fed, in which
case, other methods that use the space available may be required.
Finally, the system proposed requires the boiler to have secondary
overheat protection. If this is available, you may as well have
combined vent/feed as well, to eliminate pumping over problems, or
better still, convert to sealed pressurised operation.
I decided to post a couple of pictures to make clear what I'm on about!
The first one
http://www.mills37.plus.com/cylinder.JPG shows the existing
layout. The flow pipe from the boiler comes up through the floor, with the
flow going up through the pump to the 3-port valve - then left into the top
coil connection and right and down to the radiators. The coil return comes
out of the bottom of the cylinder, through a gate valve for balancing, and
then disappears through the floor under the pump electrics. Somewhere under
the floor, the HW and CH returns merge into a single boiler return pipe.
The system is currently vented, although I may convert it to sealed at some
time. The boiler (Baxi Solo MK I) *is* suitable for sealed operation. The
F&E tank is in the attic directly above the airing cupboard. There is a
single 22mm pipe tee'd into the flow pipe just under the floor and running
across to the LHS of the airing cupboard, where it splits into 2 pipes which
go up the wall to the attic - not visible in the picture - 22mm vent and
15mm fill.
The second picture
http://www.mills37.plus.com/cylinder2.JPG is marked up in
red to show the propsed changes, as follows:
* get rid of the 3-port valve and the 2 horizontal pipes either side of it
* extend the pump outlet pipe up higher (probably raising the pump at the
same time to get a full bore valve under it
* run 2 horizontal pipes from the top of the extended flow pipe - one going
down through a 2-port valve to the top coil connection, and the other going
down through another 2-port valve to connect into the CH flow pipe
* fit a vent at the highest point (the top right red bit)
* fit an automatic by-pass valve between the flow pipe above the pump and
the HW return - replacing the existing gate valve with a tee (I can fit a
gate valve on the inlet instead, if needed)
Moving things up like this gives me a lot more room to manoeuvre - including
space for a few full-bore isolation valves to enable component changes
without draining
Are there any glaring gotchas in my proposal?
Thanks for your interest.
--
Cheers,
Set Square
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