airlock All aspects of plumbing questions and answers, help, tips and information

[royal]

I have two related problems firstly the water supply ino the house is via a 1/2" alkathene pipe, I understand this needs to be upgraded to a larger pipe but as the pipe is under a 40yard run of tarmac and concrete it will not be replaced in the near future, the second problem is because of the reduced flow rate /low pressure I get an airlock problem,..when the hot tap is turned on full to the bath the header tank empties quickley and air is sucked into the system (the system is direct the water being heated with a back boiler in a rayburn) and the air lock manages to get into either the flow or return pipes and stops the flow of the water in and out of the cylinder, this is usually avoided by not turning the bath hot tap on full bore, but having kids in the house they occasionally forget to do this and turn the hot tap on full and may even be running the cold tap at the same time, so the problem occurs, the only way I have found to remove the air is to turn off the rayburn (oil) and drain down the system then refill and relight, now for your part is there anyway way I can restrict the flow of water through the bath hot water tap to stop this happening again? I did think that if I was to close down the gate valve between the header tank and the cylinder slightly that would slow down the flow of water into the cylinder and so reduce the flow of water out of the hot tap, would it be OK to do this? if anyone has any suggestions I would be gratefull

[Dave From Leeds]

Seems to me that your idea of restricting the flow from the cold water storage tank to the cylinder might help. In any case, it's an easy thing to try (and to reverse if unsuccessful). Only problem might be if the gate valve is seized open.

Good luck.

Dave.