flow meter

Hello,

my machine has the problem with the error message "Check water tank", so I opened it and looked at the flow meter.
Apparently nothing was dirty.
I have built up the water supply with the machine open and seen that no water pressure is built up behind the flow meter.

Concrete question:
How can I find out if the flow meter is defective or not?

Manufacturer: Bosch TES 506...

>I hope for your contributions.

Greß

Hello , Andreas .

So , as you describe it , the distance from the water tank to the flowmeter is simply blocked . With a 50 ml syringe from the pharmacy and a thin tube from the hardware store or the aquarium department you should then 'times flush from both sides.

"Defective flow meter " can only mean: no signal is sent to the control electronics, although water is flowing through .
An asterisk sits in the flowmeter that rotates at flow - a mini turbine, so to speak. A small magnet sits on a star arm and a magnetically sensitive ( "Reed"-) contact is located on the outside of the housing, which is switched once every revolution. Two thin wires lead to the transfer plug into the electronics .

If you pull the transfer plug and let any water run through the flow meter, a resistance meter - connected to the transfer plug - must indicate short pulses, each time the change from infinite to gaaaanz low resistance. This is practically the only clever measuring method. With a flashlight bulb you can not check it well because the reed contacts are very sensitive and it is enough a few x-zig milliamperes to fry them away.

"or vice versa"
Is it not the same whether the switch switches from 1 to 0, or from 0 to 1?

"how the inputs of the microprocessor in the control unit are constructed"
I wouldn't hold a measuring device there. That only gives strange results. It is best to disconnect the plug and measure only the pulse generator...

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Pessimist: Ganz schön dunkel hier...
Optimist: Ich seh ein Licht am Ende des Tunnels...
Realist: Mist, da kommt ein Zug...
Zugführer: Was machen die 3 Deppen auf den Gleisen?

Yes, of course, Danceman - with separate connection sensor side measured .

there appears the next pitfall: hopefully the sensor output is also a simple reed contact with two connections ! Meanwhile I also find flow meters which detect the encoder magnet by means of a magnetically sensitive transistor. These things have three derivatives. The trade chinese then mumbles: " NPN transistor, open collector output, pull-up resistor, signal current 20mA, duty cycle 50% "

This should, however, for most coffee drinkers the limit of their own testing possibilities far exceeded.

Who still wants to play with such a three-ribbed part (transistor output!) a little , I recommend the device, which the company Pollin Elektronik (there are also other, e.g.: Conrad , Reichelt etc.) offers as Nr 77-180 056 for only 4,95 €.

Hello , Andreas .

A big praise from me for the picture ! class , which says more than 1000 words

" Does not rotate and has high pressure loss " - that smells very much like a mechanical blockade of the counter wheel . Just as if any foreign matter had entered the flowmeter. I would try to push the turbine wheel from the exit side with a flexible wire against the operating direction of rotation. Maybe then a piece of something else falls out and the whole thing runs again. A free running meter wheel allows water to pass smoothly through the meter, but if the wheel is mechanically blocked, the flow meter has minimal passage with high pressure loss. Then the x pulses per time unit are off, the control processor recognizes the lack of water from this and cancels the process with an error message.

In case of a cable break from one of the three sensor strips, the machine would also abort with the error message .

Without insight into the circuit diagram it is also practically impossible to test the removed flow sensor within a small test circuit.

Do you have more to say than "on suspicion" ordering a new flowmeter and installing it yourself ? If the problem is solved with it, I would be very happy - and certainly still a few fellow readers - about a feedback .


Gruß..........................................Jakomo

Before you make any measurements or order any parts, you could simply open the flowmeter, you need exactly one handle (put the water tank down before...)

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Grüße, Manuel

Jura ENA Micro 9 (Küche)
Jura xF50 (Büro)
wechselnde Besetzung in der Werkstatt...
P.S.: Support gibt's im Forum, nicht per PN o.ä.

I've already opened the flowmeter and couldn't see any obstacle as to why it isn't running.
Therefore I'm going to order a new one tomorrow and will get back to you as soon as I've installed it.

--------------------
Pessimist: Ganz schön dunkel hier...
Optimist: Ich seh ein Licht am Ende des Tunnels...
Realist: Mist, da kommt ein Zug...
Zugführer: Was machen die 3 Deppen auf den Gleisen?

Hello , coffee-drinking Foristen .

It is a valuable hint to me that the flowmeter (non-destructive) can be opened . One never learns from !



The problem then looks very much like a bearing damage in the device ! What there is not all .


Thanks and greetings to all.........................Jakomo

Good evening,

at an EQ 5 I had cleaned the wheel & all the FM. The device went off for a while after that. But the message came back: check the water tank. After replacement by a new one the device then went flawlessly and still works. - So this plastic pin with the wheel on it gets uneven with time. The best way is to replace the FM with a new one.

Greeting HWS

I exchanged the flowmeter for a new one, but the coffee maker does the same thing:

- it grinds the beans
- after that comes "water tank check"

Shall I check the pipes behind the flowmeter?
Has anyone any other idea?

I don't know the type of machine. But since you have specifically named the flowmeter as a source of error, everyone has assumed that you have already checked all other possibilities! Then obviously the "old" flowmeter is still moving and may not be the problem!

Wait a minute to see if there are any ideas. But that the error message comes directly after the grinding is certainly not good. Hopefully no control defect, because other machines would still drive the BG together after grinding the beans and try to pump water. Only if then no water flows the message "Fill system" or similar would appear. This always means a problem in the water flow. Can be a pump, flowmeter or just a blockage somewhere.

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Pessimist: Ganz schön dunkel hier...
Optimist: Ich seh ein Licht am Ende des Tunnels...
Realist: Mist, da kommt ein Zug...
Zugführer: Was machen die 3 Deppen auf den Gleisen?

The note : " Can pump [.....If you enter the YOUTUBE with the search terms "fully automatic coffee maker , repair " - pretty much at the top of the list - you will get an interesting article in picture+sound high: There a tiny sealing ring blocked the suction side of the water pump by fixing the oscillating armature ! ring 'rausholt , pump again installed - coffee march ! remained unclear where this ring came from .

In the article mentioned it looks very easy to remove and clean the pump for revision. Hopefully it's just as easy in real life. That one makes such a thing only with pulled out mains plug should be natural .


New Year greetings to all coffee noses ...................Robert