Like most of the components used in home washing machines the door locking mechanism is ultra cost optimised and refined for cheap and easy manufacture. Yet it performs three separate functions. Locking the door, enabling the machine when the door is fully locked and unlocking the door after a time delay to allow a spinning drum to come to a halt before it can be opened.
This particular lock is used in many European machines including Hotpoint and Indesit.
On the basis that these assemblies are mass produced I suppose it makes it viable to use them in other applications where you need the same interlock and time delay feature. The use of a PTC heater probably means that the mechanism can accommodate a wide voltage range.
Failure of these door locks is fairly common, especially if an attempt has been made to force a door open prematurely. They're fairly straightforward to change if you're technically inclined. Some may just require removal of the top of the machine, but some may require removal of the front too, sometimes including the sealing ring which is often held in place by a spring tensioned wire.
If attempting to replace a lock then make sure you get the exact replacement for your machine's brand and model number. Also make VERY sure the machine is unplugged before attempting a repair. Traditionally washing machines were a significant cause of electrical accidents because they are an essential item in the home and can cost quite a lot to have repaired, which encouraged DIY attempts. The older machines had a lot of exposed live metal components in them due to greater mechanical complexity than modern units and cost-optimised nature of the design. Add the fact that you are reaching into a cramped metal case with wet hands and repairs posed a major electrocution risk to the unwary. Especially when the power was repeatedly turned on and off during testing and then accidentally left on.
Modern machines are much more sparse inside, but still pose a significant shock hazard due to the fact that you're reaching in amongst grounded metalwork in a wet environment.
Modern machines are very modular, so if you are technically inclined and use common sense then you can often repair them yourself with components easily sourced online.
If you enjoy these videos you can help support the channel with a dollar for coffee, cookies and random gadgets for disassembly at:-
http://www.bigclive.com/coffee.htm
This also keeps the channel independent of YouTube's advertising algorithms allowing it to be a bit more dangerous and naughty.
This particular lock is used in many European machines including Hotpoint and Indesit.
On the basis that these assemblies are mass produced I suppose it makes it viable to use them in other applications where you need the same interlock and time delay feature. The use of a PTC heater probably means that the mechanism can accommodate a wide voltage range.
Failure of these door locks is fairly common, especially if an attempt has been made to force a door open prematurely. They're fairly straightforward to change if you're technically inclined. Some may just require removal of the top of the machine, but some may require removal of the front too, sometimes including the sealing ring which is often held in place by a spring tensioned wire.
If attempting to replace a lock then make sure you get the exact replacement for your machine's brand and model number. Also make VERY sure the machine is unplugged before attempting a repair. Traditionally washing machines were a significant cause of electrical accidents because they are an essential item in the home and can cost quite a lot to have repaired, which encouraged DIY attempts. The older machines had a lot of exposed live metal components in them due to greater mechanical complexity than modern units and cost-optimised nature of the design. Add the fact that you are reaching into a cramped metal case with wet hands and repairs posed a major electrocution risk to the unwary. Especially when the power was repeatedly turned on and off during testing and then accidentally left on.
Modern machines are much more sparse inside, but still pose a significant shock hazard due to the fact that you're reaching in amongst grounded metalwork in a wet environment.
Modern machines are very modular, so if you are technically inclined and use common sense then you can often repair them yourself with components easily sourced online.
If you enjoy these videos you can help support the channel with a dollar for coffee, cookies and random gadgets for disassembly at:-
http://www.bigclive.com/coffee.htm
This also keeps the channel independent of YouTube's advertising algorithms allowing it to be a bit more dangerous and naughty.
Took mine to bits after seeing this and it fell to bits when I was pushing it around don't know who puts these together but to get that little u shaped piece of copper back is a nightmare it is just balances between the 2 parts of that copper strip and the metal piece fell out as well. So while it is simple is very delicate to put together. Getting a new one anyway but I thought I might try to mend. Thanks for showing this as I could not work out how it works I still do not understand what happens when it heats and the bit that pushes the pin down makes contact with the strip below.
Whats name of them device's please
These devices are non-serviceable. They have many plastic clips keeping them together, and for a reason. To prize them apart sometimes you need four hands and four screwdrivers. They are designed that way, so that when it is clipped together it is not to be taken apart again. Playing about with one can be deadly as if something moves from its position inside you may get a dead short blowing the main board. Ouch!
The door interlock failure is probably the most common washing machine failure, so much so after a washing machine is out of guarantee, it may be worth ordering one and keeping it handy. They are a 15 minute job to replace in some models. Then no week wait with dirty washing. Washing machines are the most breakdown prone appliances I know.
The most reliable is a the only washing machine made in the UK, Ebac. They looked at the washing machine and redesigned the bug points. It is designed to service and not throw away. The innards are simpler. The washing cycle is shorter so saving money in operation. The drain pump doubles as re-circulation pump as well. When they make an integrated washer/dryer I will be eyeing them up.
Nice to know how the interlocks work Clive, but I advise if it fails buy a new one. No cleaning contacts or anything. I noticed the door interlock on my machine is around ยฃ17 delivered.
Nice exploration and explanation of the safety interlock Mr C. It is very useful understanding how a thing works when you are faced with fixing a broken one.
I note for those with locks that do not open reliably that the fixes from the comments seem to be : Remove the plastic sliding strip. Or increase the size of the hole in the sliding strip. Or remove the lock pin. Or bypass the lock by rewiring it to disconnect the PTC and permanently apply power to the machine. Or buy a new lock and replace it, they are inexpensive.
Note that the machine model name and number needed to buy a new lock are on a sticker on front of machine inside door. To get your stuck door open use plastic cord/fishing line wrapped round door, pushed in with flathead screwdriver – to tug towards hinge side of door on latch. Or slap panel hard to reset lock. There are other methods in YouTube videos.
From other videos the method to fit the new lock is : undo the clip round the rubber door seal and push the seal back inside the drum. Undo the screws holding the door lock and fish it out from the gap between the drum and the front plate. Unplug old lock, plug in new lock. Screw new lock back in behind panel, replace door seal, refit clip.
My lock is sticking and I will probably buy a new one when I get tired of opening the door with fishing line. Stay Safe ๐
pls make a video for How a washing machine door interlock works with vax motor
Things to do before breaking your washing machine: watch this video
Always cool to see cost optimised safety critical stuff, my day job is railway signalling so also safety critical but anything but cost optimised.
congratulations. great interesting video. Does anyone know what the ptc thermistor designation is and what it's characteristics are?
amazing content sir ,, you are the only one on the internet who showing the power consumption of the lock ,, thank you !!
Hello Sir,
do you know which pin has which function on this relais?
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Thank you
My Hotpoint has a Door Locked light, and the door always unlocks a few seconds after the light goes out.
Nice design ,no wax and using PTC thermistor .is there a bimetallic strip that the PTC thermistor activates ???Safety rated switches cost a fortune compared to an identical switch .A book from CSA would help( Machine Guarding )So many switches are being used in equipment as safety switches and are not rated as safety switches !
How no water inflow in the washing machine is sensed.
Is a PTC used to maintain a temperature of the solenoid coil of inlet valve or frequency is monitored as the inductance changes with movement of core connected to the diafragm of the pressure sesneor
Thank you Big Clive. I had an issue with the door interlock on my machine and after listening to this video, I cleaned the PTC and associated contacts. Job done, all sorted. Many thanks.
I blew the plug by my washing machine long ago and have been using a thick cord from a close receptacle. I always leave it plugged in after its done because I thought it needed the power to open, and sure enough, last night, you're video is correct. Awesome video