La Marzocco marco 1000740 Service Manual - page 15
Service manual 1000740 1000741 1000742 1000750 1000751 1000752 06-12-11
Page 15 of 24
4 FLASH CYCLE
– NOT HEATING
Display pattern:
4 flashes then a short pause - repeated.
Electronic check
and action:
This checks that the temperature is increasing when the heater is on.
Measures the rate that the temperature increases in a specified time.
This error is only displayed after 20 mins of the heater being on
continuously. When the error is detected, the element and inlet valve are
turned off.
This is a non recoverable error. The machine needs to be reset when
this problem is solved.
Probable causes:
The elements have failed
Wiring fault
Action required:
Check that the resistance on the elements. If there is a reasonable
resistance (15-
25Ω)on the element it probably has not failed, so the
wiring might be at fault.
5 FLASH CYCLE
– THERMISTOR SHORT CIRCUIT
Display pattern:
5 flashes then a short pause - repeated.
Electronic check
and action:
This indicates that the Thermistor is measuring zero resistance. It
assumes the thermistor has failed sort circuit.
The element and inlet valve are turned OFF when this error is detected
This is a recoverable error. When the correct range of resistance is
measured, normal operation resumes.
Probable causes:
The thermistor has failed.
Action required:
Replace the thermistor.
6 FLASH CYCLE
– NOT FILLING
Display pattern:
6 flashes then a short pause - repeated.
Electronic check
and action:
This checks that the water in the tank cools when the inlet solenoid
valve is switched on.
This is a non-recoverable error. This checks that the water in the tank is
cooled by when the inlet solenoid valve is opened. If the water pressure
is within the specifications (5-50psi), the inlet solenoid should not be on
for more than a few seconds. If this water temperature has not
decreased by the required amount
(1 degree per minute), the inlet solenoid is switched off and the 6 flash
cycle is displayed.
Probable causes:
Mains water pressure problem or the mains water stop valve is closed.
Inlet solenoid valve failure.
Action required:
Check the mains water supply. (Note: Temporary loss of water pressure
can occur in certain sites
– particularly when various machines are
plumbed to the same mains water supply.) If the water supply is ok,
reset the machine (switch the machine Off and On again). This will reset