How do you remove an airlock from water pipes?
The short answer
The usual trick is to connect a hose between a mains-pressure tap (normally the kitchen cold) and the airlocked tap, then run the mains tap so the pressure pushes the trapped air back out. Spluttering taps, no flow from one outlet while others are fine, and banging or gurgling after work on the system are the classic signs.
An airlock is a pocket of trapped air sitting at a high point in the pipework, blocking the flow behind it. It usually appears after the system has been drained down and refilled — after a repair, a new radiator, or the mains being off — because refilling doesn't always push all the air out.
The hose trick works because your cold mains is at much higher pressure than a gravity-fed hot tap on a traditional cylinder system. Clamp a hose between the two, open both, and the mains pressure drives the air pocket back out of the way. Run it for a minute or two, then close the airlocked tap first, then the mains one.
It doesn't always work, particularly on a stubborn lock or on a system with several high points, and it isn't the answer if what you actually have is a failing pump, a blocked filter or a partially closed valve. If the tap still splutters, or the problem keeps coming back, something is letting air in and that wants finding rather than repeatedly bleeding.
Got a plumbing job in Macclesfield?
Tell us what you need and it goes straight to our local plumber — one call back, usually the same day. Free quote, no obligation.