This is a portion of my central heating system that I'm currently re-plumbing. Boiler on the left, radiators on the right. It's a 2 zone S-plan system. The boiler is downstairs, flow and return go up, into the ceiling, through the joists (roughly level) for about 2-3 meters, bend up and over another pipe (grey) and then come back down, in a cupboard, under/in the concrete slab, to the downstairs radiators. There is another pipe running parallel (not shown) that feeds the upstairs radiators. Both zones share the return pipe as shown below.
The levels in the below diagram are roughly representative, with the bridge rising up about 2 inches to get over the another pipe.
I currently don't have any air bleed valves in this part of the system and I'm unsure of if I need them/where to put them. I can't fit any to the left of the diagram, near the bend, as there is no room, due to floor joists, though there is space along the straight run of pipe. I am able to re-route the bridging pipes if I have to, so that they go under the other pipe (they'll go under the ceiling, but it'll be in an airing cupboard, so I'm not overly concerned with how that will look):
I'm not sure this really helps though, as this just moves the high spot to the longer part earlier in the run. So I'm still left with an unvented high spot.
I'm looking for a bit of advice on where I should/could put some automatic air valves really? It is possible for me to leave an access hatch in the top of the airing cupboard (right side of diagram), so that if I leave the pipework as per the top diagram, I could install an air valves on top of the each of the bridging pipes; that's the best I can come up with though and I feel like there should be a more elegant solution; I'm hoping someone with more experience might be able to point me in the right direction here!
On a separate note, my upstairs zone will have a pipe running basically parallel (without bridges) to these pipes, but I'm assuming that the radiators that will T off of these pipes will count as the high spots and I'll be able to get the air out of the system there instead. Would be good to have a sanity check on that too if possible?
Also, I'm not sure if it matters, but this is a gravity fed system.
Thanks
The levels in the below diagram are roughly representative, with the bridge rising up about 2 inches to get over the another pipe.
I currently don't have any air bleed valves in this part of the system and I'm unsure of if I need them/where to put them. I can't fit any to the left of the diagram, near the bend, as there is no room, due to floor joists, though there is space along the straight run of pipe. I am able to re-route the bridging pipes if I have to, so that they go under the other pipe (they'll go under the ceiling, but it'll be in an airing cupboard, so I'm not overly concerned with how that will look):
I'm not sure this really helps though, as this just moves the high spot to the longer part earlier in the run. So I'm still left with an unvented high spot.
I'm looking for a bit of advice on where I should/could put some automatic air valves really? It is possible for me to leave an access hatch in the top of the airing cupboard (right side of diagram), so that if I leave the pipework as per the top diagram, I could install an air valves on top of the each of the bridging pipes; that's the best I can come up with though and I feel like there should be a more elegant solution; I'm hoping someone with more experience might be able to point me in the right direction here!
On a separate note, my upstairs zone will have a pipe running basically parallel (without bridges) to these pipes, but I'm assuming that the radiators that will T off of these pipes will count as the high spots and I'll be able to get the air out of the system there instead. Would be good to have a sanity check on that too if possible?
Also, I'm not sure if it matters, but this is a gravity fed system.
Thanks
