I recently changed a kitchen tap for another, installing a single-hole mixer. I had isolated the water at a stopcock under the kitchen sink unit. After a few days, a loud banging started when the cold water tap was used. It stopped for a couple of weeks but has now returned. I've been asked to get it fixed.
The user had thought that it was caused by an air-lock. I told them that you'd only get an air-lock on a tank-fed system and that it was most probably water hammer. However, they rang the manufacturer's technical help dept & they immediately said it was an air-lock.
I'm a bit baffled by this. I can't imagine an airlock in the 18" of pipe I put in; it rises continuously & there's no high-points. I'm now inclined to think the tap is defective and the air-lock story is an excuse. I have to identify the real cause and get it fixed. Has anyone else ever heard of this air-lock business with mains water?