Q: I just had a new washer machine installed I it running well except when the drum fills with water the shutoff mechanism is so hard that is caused the pipes in the basement to shake -- the noise is so loud the dogs bark and think someone is in the basement. It is like the water shuts off so hard that it causes a reaction in the pipes.
Do you know if this is something that will go away or should I call Sears to check the problem and possibly bring me another machine - Maytag model.
A: I don't think the problem is in the machine. Your description sounds like "water hammer".
"Water hammer (or, more generally, fluid hammer) is a pressure surge or wave caused by the kinetic energy of a fluid in motion when it is forced to stop or change direction suddenly. It depends on the fluid compressibility where there are sudden changes in pressure. For example, if a valve is closed suddenly at an end of a pipeline system a water hammer wave propagates in the pipe. Moving water in a pipe has kinetic energy proportional to the mass of the water in a given volume times the square of the velocity of the water."
Most modern homes have devices called water hammer arresters ( they're called various things such as air chamber, air cushion, water capacitor, etc.) . They are air filled chambers connected to the plumbing that let the pressure wave dissipate harmlessly into a cushion of air. If your banging has been happening forever you may not have one.
Sometimes these arresters become waterlogged. Try this. Turn off the water to the house at the entry. Find the lowest faucet in your house--often this is an outdoor garden hose faucet--open this faucet and then open a few of the indoor faucets at high locations such as upstairs or at a wet bar and let the low faucet drain for 5 minutes or until it stops dripping, whichever takes longer. Close all the faucets and turn the main back on. Note: When you first start using water again there will be air in the lines and it may spit and sputter with some vigor.
If the piping makes a 90 degree turn to enter the washing machine, you may be able to solve the problem by adding a "T" in place of the 90 degree elbow and putting a 18" capped piece of pipe on the top of the "T". This will act as your arrester - it is filled with air and provides a cushion.
Labels: water hammer
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