Chapter 6 Control system diagram
SMSO-2-02.06- 15.07.03 199
6.5.15 Flow meter
36V
5V DC
36V S L1, N
Operating condition
When making a serving of “coffee” the coffee water flowmeter controls the amount of water measured out.
Symptoms
“Flowmeter fault” message displays.
NOTE: This message displays if there is a fault or defect anywhere in the water system. Therefore, the fault message does not
necessarily indicate a defect in the actual flowmeter or its measurement circuit, but merely states that the water flow in the brew-
ing system is not functioning or is functioning unevenly. (For example, a cogged baffle that is preventing the water from flowing
can cause this fault message; in this case, the flowmeter itself and its relevant control section would be intact.)
Procedure
Process
step
Check Possible cause Remedy
1
Measure voltage at plug X 13 5/7
on unit control system:
5 V DC ?
Check the voltage supply (see
“Power PCB, control voltage”)
Voltage supply failure / faulty
2
Measure voltage at plug to flow-
meter, loosen the plug casing and
lift:
+, GND =5 V DC ?
Plug contacts on unit control sys-
tem faulty / oxidised
Cable broken or pulled out of plug
The flowmeter is faulty
Check / replace plug contacts
Replace cable (Caution: Incorrect
polarity will destroy the flowme-
ter!)
Replace the flowmeter (see secti-
on 5)
Switch off voltage:
Install a new flowmeter and con-
nect.
Restart the machine
If the “flowmeter defect” message
continues to display:
Faulty unit control system
Replace unit control system
NO
YES
YES
NO
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