Installing pipework to avoid airlocks

[Matt0029]

How it best to install pipework to best avoid airlocks with gravity hot water. Install level or slightly down hill in direction of flow? Thanks

 

[fowlerboi]

As long as you have a decent head on pipework you're working on and that there isn't a massive high spot you'll always clear the air. Typically pipes go in notched into the joists at the same depth regardless of what the spirit level says.

The only time I've ever struggled with air locking hot water was during a loft conversions where we moved the cistern onto the deck and had temporary pipes running along the floor keeping the house going. A long run roughly horizontal to the drops in the airing cupboard but it trapped air all along that run. We chucked the cistern up on a 2inch platform and it was sufficient to clear it. Good fun removing 100L+ of water from a cistern which is air locked though.