Why do washing machines prevent opening the hatch just after the washing cycle ends?
Why do washing machines prevent opening the hatch just after the washing cycle ends?
Most washing machines have a timer that prevents you from opening the hatch just after the washing cycle ends. Instad you must wait for the timer to go off, usually a minute or two, before you can open the hatch.
Why? Would letting the user open the hatch immediately after washing ends pose any safety or other issues?
Well, imagine someone opening the door if the water hasn't fully drained out and the ensuing mess. If you're wondering if someone is stupid enough to do that, then the answer is unequivocally yes. There is a reason the door locks for that amount of time - so somebody doesn't brain fart, open the door, and flood the laundry room.
So why not make the washing cycle end when the water has fully drained? I get the impression the timer starts after the drain.
Maybe that's your machine being oddly programmed. Every machine I've seen unlocks right after it finishes it's cycle. It can also be stopped and unlocked anywhere halfway, but it takes some time to drain the water (usually a few seconds, not a full minute like you mentioned originally).
what device would you use to check the water has drained?
I have been saved by that washing machine lock on a number of occasions
It’s not a component aware system. The last phase is generally the spin cycle. The controller knows to trigger the spin cycle, it knows to stop the spin cycle after a period of time. What it doesn’t know is whether those things actually happened. Particularly, it doesn’t know that the drum has actually stopped spinning. So, it just wait a predetermined amount of time before unlocking the door.
In the case of my own device the door actuator uses a wax motor. Put simply, current is changed to heat which melts the wax, pushing a pin the locks the door. To open the door, current is removed, the wax cools, hardens and shrinks and the pin slides back. Now the door can open. So, even if I remove power during a cycle the door will eventually unlock as the wax cools.
Of all the answers here, this definitely seems like the right one and the only one that makes sense.
Many machines use a bimetal to lock the door, a stupidly simple design. Metal heats up, bends and triggers the lock. It takes a while to cool down which is why it'll take a while to unlock even if you unplug the machine.
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My bet would be it's waiting for temperature to drop.
Edit for the downvoting folk: Some of the profiles of my washing machine have temperatures of up to 90°C
I would bet that the water for the rinse cycle would be cold though.
It checks if the water is really truly out so opening the hatch is safe (as in no water coming out causing water damage). And for that it waits a time so the water has time to gather in the bottom.
But why not just beep after that? What’s the point of beeping before the door is unlocked?
Mine beeps and simultaneously unlocks the door. Beeping befor you can open it truely does sound stupid… Never had that with any washing machine here in Switzerland though.
My best guess is safety, if you had a heavy load in there the momentum could keep the drum spinning much longer than normal. I'm sure they could add a sensor to check, but that's just an extra cost. So rather than allowing you to open the machine while it's still spinning and possibly injure yourself reaching in, they keep it locked for a few more minutes.
It's safety for sure. Mine is pretty new and I can tell that it has a sensor for the drum rotating - it doesn't unlock until movement has stopped. You could really mangle a finger if you got it caught between the moving drum and the stationary housing. The bitch is that mine is energy efficient and it spins easily, so a heavy load will keep spinning a long time.
It's so that the machine elves have some time to hide!
On a serious note, I found this explanation here:
Washing machines must have some way in which you can lock the door closing mechanism when the machine is started up and then unlock them with a certain delay (normally two minutes) after the current has switched off via the program or on/off switch, in order to ensure that the door cannot be opened while some of the components are still rotating initially (in particular the motor and the drum of the spin-dryer).
Washing machines have a bi-metal strip inside the door lock which is heated by PTC Heater (resister) when live and neutral are activated on to the pcts it heats up and bends the bi-metal strip which then moves the arm to activate the common terminal and push a pin into the closed door to lock it in place. Once this has happened (usually a second or so see video) the power then can flow through to the common wire, and therefore on to the rest of the machine allowing it to start.
I always assumed it was to give the water time to drain out so when you open the door it doesn’t just spill out over the floor
Surely it could just wait with signaling the end of the program until the water has drained?
The instructions say that it's too make sure all the water has drained.
It's to keep people from sticking their arms in there before it coasts to a stop.
Mine doesn’t do this, but it does do a few slow spins right at the end so that everything settles to the bottom. Maybe yours is also doing this by waiting?
Possibly.
My washing machine is a top loader and has a pause button that will stop the water fill/spin cycle so you can open the door. The washer waits until the cycle pauses completely then unlocks the door
Am I missing something? I've opened the lid multiple times while the washer was going. All that happens is the water shuts off until you close the lid again. Never seen a washer that locks actually.
Are you sure you're talking about a washing machine and not a dish washer?
There's still water in the drum. Ew wet clothes.
I got a side loader and it generally is spinning at least a little slowly until right before the timer goes off. Generally I can push the pause button at any point during the wash and after a few seconds it will unlock. My top loaders i used to be able to open at any time during the wash.
I imagine they have a buffer period to let the load stop spinning but you probably can override for earlier if you really want.
My washing machine can be opened when running at any time so no idea what washing machines you have. Considering I want it to be going already when I add detergent.
Front-loaders usually restrict you from opening the door before they're drained, or else some idiot would flood their apartment.