In a previous video I took apart my new washing machine to show how modular it was inside. I thought the water level switch was the usual multi-switch pressure transducer, but a few viewers mentioned that it is an inductive transducer that sends pulses to the controller to indicate the water level.
So I went online and bought a used one so we can take it to bits and see how it works.
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
So I went online and bought a used one so we can take it to bits and see how it works.
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
I'm guessing you have at least a bachelor's degree in electrical engineering and some years of experience.
Kako ga postaviti
How would one test that to see if it was faulty?
Nice vid. funnily enough this is called an analog water level sensor or pressostat. The old one which has 2 modes: On / off is a digital pressostat, because on=1/ off=0. It also clicks when you suck on it.
Very nice and useful. How would I trick it to fill with more water?
Its called pressure switch
Here is a snippet from a service manual of a frigidaire washer/dryer (laundry center) that touches on the water pressure/level sensor.
"
9.11 Pressure Sensor
– FFLE3911QW and
FFLG4033QW
9.11.1 General Characteristics
The Pressure Sensor is an analogue device that controls the
water level in the tub, used in models with electronic control
system, and it is directly connected to the Main Control
Board.
A tube is connected between the bottom of the Tub and the
Pressure sensor.
When the tub is filled with water,
it creates a pressure inside the
hydraulic circuit that causes the
membrane to change position. This
in turn modifies the position of the
core inside the coil, thus changing
the inductance and the frequency of
the oscillating circuit.
The Main Control Board recognizes how much water
has been filled into the tub according to the frequency.
Operating frequency varies according to the quantity of
water in the tub
"
Specifications
Pressure Frequency Diagram
( At Water Level “0” mm (empty tub) Frequency will be 45.4 Hz )
Mm H20* – Hz* : Points with 100% control of frequency output on assembly line
Pressure (mm H2O) Nominal frequency (Hz)
Water Level at
0* 45.400* Tub empty, 0 pressure and frequency is 45.4 Hz
150* 43.140*
200* 42.350*
350* 39.990*
500* 37.772*
600 36.560 Tub if full and frequency 36.560.
Mm H20* – Hz* : Points with 100% control of frequency output on assembly line
After seeing your video I wanted to do the same with my sensor.
Looks nearly identical. However, the LED was constantly on. And I laughed after opening the case.
From the outside there are three contacts: S+, GND, S-. But inside there were no electronics. The winding is connected directly to S+ and S-. Only a small capacitor goes from S+ to GND inside.
The manufacturers have saved even more costs and moved the IC to the mainboard. 😂
my washing machine empties all the water every time I change the program. How can I trick the pressure switch into believing for a few moments before starting the new program that there is no water?
Thanks Clive! No high tech CPU sensor here just good old CMOS 4000 logic! The design has elegant simplicity. Cool teardown.
Very gratefull explanation…🙂
Great video. helped me with my mechatronics assignment. Thank you!
have this with resistor 101 and 103,
replaced with other (unknown inside) and not working. how to determine it from outside label?
I just came across one today, now i know how to test them, if I didnt brake it in the first plave (i shorted +5V and Out, Grnd was never touched nor shorted)
Just finished fixing my washing machine, this was invaluable during diagnostics. Thanks!
Thanks for that Clive, very interesting, I suppose using this method the manufacturer can control and adjust the water level through software rather then mechanical methods depending on the market it is being shipped to.
I have a washing machine Ariston Aq8L with similar sensor. The output is a square wave of 5V with range that goes from 10,75hz empty to 10,62hz with 2 liters of water. I am wondering if this the appropriate dynamic range as very often the machine fails to drain and starts blinking. This is range with drum stationary as when spinning the drum moves a lot as dampers are worn out and when spinning with normal load jumps between 10,26hz, 10,31hz, 10,36hz and 10,42 hz.