La Marzocco marco 1000740 Service Manual - page 14
Service manual 1000740 1000741 1000742 1000750 1000751 1000752 06-12-11
Page 14 of 24
4.6. TROUBLESHOOTING – DIAGNOSTIC GUIDE:
NOTE FOR THE ECOSMART RANGE IN ADDITION TO THE STATUS LED FLASHING TO
INDICATE AN ERROR
– THE DISPLAY WILL ALSO PROVIDE INFORMATION
2 FLASH CYCLE
– BELOW LOW LEVEL
Display pattern:
2 flashes then a short pause - repeated.
Electronic check
and action:
This indicates that the low level circuit is open i.e. the probe is not in
contact with the water.
The element is switched OFF at this stage and the inlet is left ON.
(note that if this is a low probe wiring fault, the water will stop at the high
level probe regardless of the status of the low level).
This is a recoverable error i.e. the machine does not need to be reset
when the problem is solved. (e.g. if a closed mains water stop valve is
the problem, opening the valve will allow water into the machine and
normal function will resume when the low level probe is reached)
Probable causes:
The water level is below the low level probe, which is normal when the
machine fills for the first time. (Can be flashing for up to 2 min at start
up)
The low level probe wire is disconnected, or there is another wiring fault
(eg. a bad earth (return) connection between the PCB and the Tank)
Action required:
Check that the water pressure is OK and ensure that the stop valve is
open.
Check that the inlet solenoid is working.
If the water level is above the level of the low probe, check the probe
circuit wiring
3 FLASH CYCLE
– THERMISTOR OPEN CIRCUIT
Display pattern:
3 flashes then a short pause - repeated.
Electronic check
and action:
This indicates that the Thermistor is measuring such a large resistance
that it assumes the thermistor circuit is open.
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 probe is unplugged from the 4way connector on the PCB
or the thermistor has failed open circuit.
Action required:
Check that the thermistor is plugged in to the PCB correctly. If it is,
replace the thermistor.