How to clear hot water air lock?

[Glen63]

I recently installed new hot and cold feeds to a new downstairs cloakroom. After refilling the system the hot taps were all dribbling, spluttering and showing signs of an air lock. I attached cold mains to a hot tap and left it running for 15 minutes, while opening up each hot tap. They all started flowing nicely and I had water flowing from the vent pipe into the hot water tank in the loft. Once I disconnected the cold mains feed though, the hot taps all dried up again. What should I try next please? For background, I have a pressurised central heating system and a Telford Copper Cylinders hot water cylinder on the same floor as the upstairs taps.

 

[John.g]

Its possibly a air lock in the cold supply from the CWST to the cylinder, ensure that the isolating valve from the CWST to the HW cylinder is open then do the same as you did above but hold your finger/hand over the vent, this might force reverse flow through the cold feed back to the CWST and clear it?.

 

[Glen63]

Its possibly a air lock in the cold supply from the CWST to the cylinder, ensure that the isolating valve from the CWST to the HW cylinder is open then do the same as you did above but hold your finger/hand over the vent, this might force reverse flow through the cold feed back to the CWST and clear it?.

You’re a genius, thank you! Held my thumb over the vent pipe while it was running into the CWST for 30 seconds and it’s cleared the air lock. All hot taps working properly now. Now I know I can clear an air lock I can be confident in working on the pipes once more. Can’t thank you enough John.