I've been pondering running some central heating/cooling pipes in the loft. The general idea is an 'up and over' using flexible plastic pipe with no joins to avoid the risk of leaks. Pipe goes up from one room, runs horizontal in the loft, then bends down to another room. Pre-insulated pipe so no worries about losses or condensation - mostly 16mm but possibly some
32mm. Flexible plastic can get into spaces without access that would be very awkward to run copper. It's a pressurised system.
How do you deal with air in the pipes in this scenario? Normally you'd have a bleed valve at the top of the system where the air collects - either manual or automatic. But that would make a joint in the pipe. Is there a way to force the air out of the system somehow?
I'm thinking that any system will need to be drained down from time to time and when refilled you need to get the air out. For these pipe sizes, will natural circulation pressure be enough to push it out? Would it work to have a port where eg suction could be applied? Or is this a complete no-no?
Also, is there a way to safely run thick pipes through joists without compromising structure? eg the 32mm pipes are 76mm od after insulation. Is it sufficient to have some kind of steel to go around the penetration? I'm seeing things like:
Thanks Theo