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.