"Stephen" wrote

Hello,

A couple of years ago I converted our gravity-fed HW into a fully
pumped CH system.I put all the pumps and valves in the airing cupboard
after a tee in the vent pipe, such that there is always a clear run
from the boiler to the top of the header tank.

I have been "encouraged" by SWMBO to relocate the pump and valves into
the kitchen, to free up room in the airing cupboard and to reduce
whirring noises in the night. This leaves me with a dilemma over what
to do with the vent pipe.

The pipes that go upstairs would be one pipe for CH and one for HW but
both of these would be "behind" a motorised valve. Is the easiest
thing to add a new pipe that runs direct from the boiler flow to the
header tank? Because it is designed to carry boiling water in an
emergency, does it have to be copper all the way?

I'm not sure whether I could use my existing pipe work but with a
valve such that it would short-circuit the pump and motorised valves
and allow water to flow in an emergency (the vent is tee-ed off the HW
cylinder pipes). Is this allowed? I'm thinking that the rules probably
say it must be a completely open pipe with no valves all the way to
the top of the header tank, just in case the valve fails?

Thanks,
Stephen.

Make sure you look very carefully at the relative positions of the pump,
vent and water make up connections.
Certainly the vent and water make up need to be close to avoid either pump
over or suck down. These both lead to fresh air being introduced to the
system and all the headaches associated.
Google "pump over" on this group and you should find chapter and verse from
one of its most prolific contributors (the late Andy Hall) who was certainly
an authority in such matters.

The other issue that may not have occurred to SWMBO is that relocation of
the pump will probably lead to a cooler airing cupboard.
Our system was much like the one you are considering and the airing cupboard
was useless for clothes drying! Having moved the pump and valves in there
its a useful part of the laundry circuit now.


HTH

Phil