Chapter 6 Control system diagram
SMSO-2-02.06- 15.07.03 197
6.5.13 Instant heater – “coffee”, 3kW heater
36V 5V DC
36V S
L1, N
Operating condition
With correct voltage supply, the water is heated in the “coffee” instant heater (note warm-up time!)
Symptoms
The water in the “coffee” instant heater does not heat.
Procedure
Relay 11 is triggered for approximately 4 seconds in the initial test. The measurement must be made during this time.
Process
step
Check Possible cause Remedy
1
Take voltage measurement at the
connection terminals to the ma-
chine:
L1, N:
Mains voltage ?
Check the mains connection (see
“mains connection”)
Fault in mains connection
2
Take voltage measurement at
power relay (power circuit):
Input (2), N
Mains voltage ?
Output (4), N
Mains voltage ?
Cable broken or pulled out of
terminal / plug
Check control voltage:
22-28 V DC ? Plug contact X43
faulty/oxidised;
Flat plug not correctly connected
Faulty power relay
Replace cable or reinsert it into
the terminal
Check / replace the plug contacts/
cable
Re-connect the flat plug on the
plug-in contact stud
Replace power relay
3
Take voltage measurement at
Klixon input:
Mains voltage ?
Cable broken or pulled out of plug
Flat plug not correctly connected
Check / replace the plug contacts
/ cable
Re-connect the flat plug on the
plug-in contact stud
4
Take voltage measurement at
Klixon output:
Mains voltage ?
Electrical circuit interrupted by
safety thermostat; check machine
for any faults.
Correct the fault; then reset
(press the red button).
Resistance measurement at heating cable lugs.
Switch off voltage
Pull out cable from plug-in contact studs
5
Measure resistance at heating;
nominal resistance:
17 Ω ?
Faulty heater Replace the instant heater (see
section 5)
Power circuit operating correctly.
Heating still not functioning:
Possible error in “temperature
sensor” measurement circuit or
programming error
Check the “coffee” temperature
sensor
NO
YES
NO
NO
YES
NO
YES
NO
YES
ES
NO
To Next Page
Loading...
Need help?
General
