Shut off valve for washing machine

I have been doing this for years with the old gate valves, I would assume if anything that the ball valves you have would be more durable.

nate

That is its purpose. You'd better start doing it always NOW and save doing it sometimes for when you have the steel hoses. (You should do it always then too, but my point is you have your plans backwards)

I've been doing this for about 3 years, without incurring any problems. And yes I use ball valves.

Of course it will wear out over time. Everything mechanical eventually does. OTOH, if you don't use the shutoff, it may stick in the on position and not be able to turn off when needed. DAMHIKT

??

"Don't ask me how I know that."

A new one for me. Thank you.

Going back (way back) to my mother's time, the one-lever shutoff valves have lasted about 20 years. Besides the obvious hose-burst that may occur by leaving the valves on, there's an additional reason for shutting them off when not in use: The water pressure, over time, deforms the mixing valve in the machine, eventually causing the solenoids to stick open or closed, resulting in either no water delivery or no temperature selection.

When you shut the valve off what do you think happens to the water pressure that's trapped between the S/O valve and the machine solenoids (aka, hydraulic lock)? Unless there is a way for this pressure to bleed down it will remain high and will remain the same (or near) as the supply pressure. Disaster prevention is the best reason for keeping the shutoff valve closed except when the machine is in use. MLD

I thought I missed something...but I agree with your thoughts.

OTOH I've never had a hose disaster in 25+ years...just lucky I guess, but then again, I replace the supply hoses fairly regularly (5 years or so) and have never shut the supply off other than for maintenance.

I'm confused by the physics here. Water isn't compressible, so what is the source of this trapped pressure?

The main water line. There is pressure either from the well or city line, in the piping at all times. If you close valves located midway in the pipes, the pressure remains constant. In the case of a washing machine hose, if the hose were to break with the valve closed, the only leak is what water happened to be in the line.

Think of one of those long balloons, cut the end off and pinch it (washing machine valve), now blow into the balloon from the other end until you have a pressure equivalent to your water pressure. Pinch off that end (shut off valve). What happens to the air in the balloon? Its still at pressure isn't it? If you want to relieve the pressure, then you have to open the unpressurized end. The only way to do that is to either unscrew the fitting at the machine and deal with the drip, or cycle the machine through a fill cycle - the only water it will get is what's in the hose.

Closing the supply valves to the washing machine, when the machine is not in use, is cheap insurance against a flood caused by a failed hose. However the steel wrapped hoses can still fail since the line pressure is held 100% by the rubber.When I replaced my rubber hoses with steel wrapped ones I was told that they offered no increased burst protection. Joe G

None? Is the idea that they'll do better in a knife fight?

Poor example. The balloon expands when blown up and contracts when able thus maintaining the pressure.

Harry K