Do you know what this is?
Well, as you know we are right-on, eco-warrior types (aka, cheapskates) and we have a variable electricity tariff so it’s cheaper (and greener) for us to run our appliances in the middle of the night. Our washing machine and dishwasher aren’t terribly hi-tech, but they do have a delay function that allows us to choose a start time in the middle of the night the matches the cheapest (or greenest) electricity rate.
However, the washing machine would make a banging noise as it was running which was particularly annoying at night. As you know, I’m very handy and skilled at DIY (😉), so I had a look at the machine. It didn’t seem to be rocking and knocking into the housing. The drum seemed to be spinning smoothly. It was odd that the banging could be heard right through the house, so I looked at the pipework and that was fine; as with most washing machines it’s connected to the cold-water supply using a flexible hose, so no vibration there.
I turned to the Internet to search for a solution and, as with so many of these kinds of jobs, the trick is to find the name of the problem. Once you have the name, solutions, products, and videos reveal themselves. In this case, the banging we were hearing was something called ‘water hammer.’ This is when a valve closes too quickly and causes pressure to travel back along the pipes and rattle any loose ones. Armed with this knowledge, I was able to find some videos of people with the same problem and see how they solved it.
So, this picture is of a water hammer arrestor, and it goes between the appliance (in our case our washing machine) and the cold-water feed. It fitted nicely, in-line with the flexible hose and, frankly, works great! The arrestor absorbs the backpressure and silences the banging!