How To Clear An Airlock In Hot Water System
An airlock in your hot water system occurs when a pocket of air gets trapped in the pipes, blocking the flow of water. This usually happens after maintenance, a leak, or if the system has been drained and refilled. Here is a comprehensive guide on how to clear an airlock, ranging from the easiest DIY methods to the professional solution. ⚠️ Safety First
Turn off the boiler/heater: Before starting, turn off your boiler or immersion heater to prevent the system from running dry and overheating the pump. Be careful with hot water: Even if the flow is blocked, residual water in the pipes may be scalding hot.
Method 1: The Hosepipe Technique (Most Effective DIY) This is the standard method for clearing airlocks in a gravity-fed system (where you have a cold water tank in the loft). It uses the pressure from the cold tap to force the airlock out of the hot water pipe. What you need: A standard garden hose or a washing machine supply hose (a "double-female" connector hose). Steps:
Identify the taps: Find a cold water tap (mains fed or tank fed) and the hot water tap that is suffering from the airlock. They are often located next to each other in the kitchen or bathroom. Connect the hose: how to clear an airlock in hot water system
Attach one end of the hose securely to the cold tap . Attach the other end to the hot tap . Tip: If the hose doesn't screw on, you may need to hold it tightly against the tap spout, though this is messier and less effective.
Turn on the taps:
Turn on the hot tap first. Turn on the cold tap fully. An airlock in your hot water system occurs
Wait and listen: The cold water pressure will push backwards into the hot water pipe, compressing the air bubble and forcing it back into the hot water cylinder.
Leave them running for 30 to 60 seconds. You may hear spluttering or gurgling sounds as the air moves.
Turn off and test:
Turn off the cold tap. Turn off the hot tap. Disconnect the hose. Turn on the hot tap slowly. The water should now flow freely.
Method 2: The "Bucket Flush" (If you have no hose) If you do not have a hosepipe handy, you can try to manually force water back up the pipe using a bucket and a cloth. This is messier and requires a bit of effort. Steps:
