pipes

pipes thumping

hi. my water lines are making a thump when some sources are turned off quickly. they make the thump every time the washing machine change cycles. any thoughts on what it is and how to fix. tks much

Shutting off water quickly causes a hammer in the pipes. If any part of the piping is loose and able to move, you get banging of the pipe against the studs, etc,


If the problem is new, then suspect that increased water pressure may be the cause. Check you house pressure with a small, inexpensive gauge. Should be in the 40 to 80 PSI range. Typically 50 to 60. Anything over 80 must be dealt with.

bang

You are getting a water hammer......

Get two shock suppressors and tee them in on the hose connections at the washer. Or install a small expansion tank on the cold water side of the water heater.

Or you can try this.....shut the water supply to the house and open every faucet and flush the toilets and go away for half a day to let everything drain. This will let the air chambers that are probably in your house drain too.

Turn the water back on after shutting all of the faucets. Take all aerators off from the faucets, so they stay free of dirt and open one faucet at a time, to let the air out of each supply line.

This may restore the ability of your built in air chambers to absorb the shock of running water that suddenly stops moving when the washer stops filling or when someone closes a faucet abruptly......

banging

You are assuming they have air chambers in their system. I haven't seen an air chamber in this area since I moved here 33 years ago. And if they do have them it is unlikely they will "recharge" no matter how long the system is turned off for, since it is very unlikely all the water will drain out of the piping in the wall so that air can get into any air chambers, assuming they are not waterlogged to the point that they will not release the water, just as a water heater will not drain until you allow air into the top of it.

A good DIY project

You could add air chambers at each offending fixture, external to the finished wall if necessary. They wouldn't win any House Beautiful awards, but they would stop the noise, and possibly prevent damage to the pipes inside the walls. You could make them yourself or buy them ready-made -- they're just a vertical section of pipe (I use 3/4", about a foot long) capped at the top. They fill with air, and absorb the shock when the water column is suddenly stopped, especially when an automatic valve (e.g., toilet, washing machine) is closed. There's usually no noise when a manually=operated valve is closed, unless it's closed very rapidly.

bang

Sioux Chief makes washer shock absorber that fit between the wall valve and the hose. A banging noise has to be addressed at the point where it occurs, not at the water heater or someplace else in the system.

Banging

Your right it should be at the source of the noise, I think I suggested that first.

But an expansion tank would also absorb the shock any where in the house. Been there and done that.

I wouldn't make the suggestions if I hadn't done it before more than once.