Problem Solving - La San Marco 85-S Serie Modo De Empleo Y Mantenimiento

13. Problem solving

PROBleM
1. The boiler is full of water
and the water flows out of
the safety valve.
2. The safety valve trips in
and vents the steam.
3. The machine was started
properly but the water in the
boiler does not warm up.
4. There is no water flowing
from a serving unit.
5. The programmed servings
of espresso coffee are not
constant or vary on the dif-
ferent units.
6. It is not possible to pro-
gram the serving quantities
on unit 1 and to copy them
on the other units.
7. Displacement meters alarm.
8. Autolevel alarm.
9. The machine is switched on
(the main switch is in posi-
tion 1 or 2 and the signal
light is lit) but the electronic
control is out of order.
38
CAUse
• One of the outflow lines from
the boiler or from a circuit of
the unit has a leak.
• Malfunction of electrical system
(the electrical heating element
is always connected).
• Pressure increase in the boiler
(the safety valve trips in at 1.9-
2.5 bar).
• The electric heating element is
defective or is not connected.
• Coffee ground too fine or
excessive quantity for type of
filter used.
• Clogged water circuit.
• Defective solenoid.
• Abnormal operation of the
electronic control unit or of the
displacement counters.
• Leak from serving unit solenoid
valve.
• Abnormal operation or defective
displacement meter of unit 1.
• Displacement meters jammed
or defective.
• Defective wiring.
• Lack of water in the autolevel
circuit.
• Main water supply valve
closed.
• Faulty autolevel solenoid.
• The electric wiring of the elec-
tronic control unit is defective.
• The electronic control unit is
defective.
sOlUTiOn
• Check the autolevel circuit, the man-
ual charging button, and the boiler
heat exchangers.
• Replace worn or damaged parts to
eliminate the leak.
• Check the wiring that feeds the heat-
ing element and the pressure switch.
• In the machines with electronic tem-
perature control, check the proper
operation of the electronic control
unit, the triac, the level probe, and the
electrical wiring.
• Check if the heating element is con-
nected to the power supply.
• Check if the heating element safety
thermostat has tripped in and check
its proper operation.
• In the machines with electronic tem-
perature control, check the proper
operation of the electronic control
unit, the triac, the level probe, and the
electrical wiring.
• Adjust the grinding coarseness and/
or the quantity of ground coffee.
• Check that the injector, the upper
circulation tube, the spray nozzle
and the solenoid of the unit are not
clogged.
• In the machines with electronic
metering, check the displacement
meter and its valves.
• Check the solenoid of the unit, its
wiring and the fuse in the electronic
control unit.
• Program the serving quantities sepa-
rately on each serving unit. If the
problem persists, replace the dis-
placement meter of the serving unit
affected.
• Replace the solenoid valve of the
serving unit.
• Check the control unit-displacement
meters electrical wiring.
• Replace the displacement meter.
• Replace the displacement meter.
• Check the wiring and its connections,
the control unit and the fuses.
• Check the hydraulic circuit of the
autolevel.
• Check if the on-off valve on the water
supply is open.
• Replace the autolevel solenoid.
• Check the electrical wiring, the elec-
tronic control unit and its components.
• Replace the electronic control unit.