Check out the tables below to understand the problem with your La San Marco coffee machine and fix it. This information will not only help you with troubleshooting the appliance right now but will also enable you not to make the most common mistakes and in this way not to let issues with the coffee maker get out of hand in the future. There are separate tables for different model ranges.

La San Marco SERIES 85 coffee machine troubleshooting

PROBLEMCAUSESOLUTION
The boiler is full of water
and the water flows out of
the safety valve.
One ot the outflow lines from the boiler or from a circuit of the unit has a leakCheck the autolevel circuit, the manual charging button, and the boiler
heat exchangers.
Replace worn or damaged parts to eliminate the leak.
The safety valve trips in
and vents the steam.
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).
Check the wiring that feeds the heat-
ing element and the pressure switch.
In the machines with electronic temperature control, check the proper
operation of the electronic control
unit, the triac, the level probe, and the
electrical wiring.
The machine was started
properly but the water in the
boiler does not warm up.
The electric heating element is defective or is not connected.Check if the heating element is connected to the power supply.
Check if the heating element safety thermostat has tripped in and check its proper operation.
In the machines with electronic temperature control, check the proper operation of the electronic control unit, the triac, the level probe, and the electrical wiring.
There is no water flowing
from a serving unit.
Coffee ground too fire or excessive quantity for type of
filter used.
Clogged water circuit.
Defective solenoid.
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.
The programmed servings
of espresso coffee are not
constant or vary on the different units.
Abnormal operation of the electronic control unit or of the
displacement counters.
Leak from serving unit solenoid valve.
Program the serving quantities separately on each serving unit. If the problem persists, replace the displacement meter of the serving unit affected.
Replace the solenoid valve of the serving unit.
It is not possible to pro-
gram the serving quantities
on unit 1 and to copy them
on the other units.
Abnormal operation or defective
displacement meter of unit 1.
Check the control unit-displacement meters electrical wiring.
Replace the displacement meter.
Displacement meters alarm.Displacement meters jammed or defective.
Defective wiring.
Replace the displacement meter.
Check the wiring and its connections, the control unit and the fuses.
Autolevel alarm.Lack of water in the autolevel circuit.
Main water supply valve closed.
Faulty autolevel solenoid.
Check the hydraulic circuit of the autolevel.
Check if the on-off valve on the water supply is open.
Replace the autolevel solenoid.
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.
The electric wiring of the electronic control unit is defective.
The electronic control unit is defective.
Check the electrical wiring, the elec-
tronic control unit and its components.
Replace the electronic control unit.
The machine feeds water
from one serving unit
although the serving has
not been selected
Solenoid and|or pump fed continuously.Short-circuited control unit relay.
Replace the electronic control unit.
85 S models: one unit
serves water continuously.
Electric circuit of unit improperly connected.Check the connection and correct it.
The steamer discharges
only small quantities of
steam or water droplets.
Worn gasket on tap.Replace the gasket.
Small drops flow out of the
water tap.
Worn gasket on tap.
Leak from solenoid.
Replace the gasket.
Check the solenoid and if necessary replace it.
The unit emits a whistle
after serving the coffee.
Faulty operation of expansion valve.
High pump pressure.
Check the expansion valve and if necessary replace it. Calibrate the valve at 12 bar.
Check the pump operating pressure.
Calibrate the pump at 9 bar.
The filter cup comes off the
serving unit.
Worn gasket under the filter cup.Replace the gasket.
Clean the serving unit and the filter cup.
When coffee is being served,
some of it drips out of the
edge of the filter cup.
Worn gasket under the filter cup.Replace the gasket.
Clean the serving unit and the filter cup.
Water leaking from the
drain of the serving unit
solenoid.
Malfunctioning unit solenoid.
Water leaking from unit cooling system.
Check the unit solenoid.
Check the plunger on the solenoid and clean the solenoid.
Replace the solenoid.
Check the cooling tube and the seal rings inside the unit.
Light cream (the coffee
flows out of the spout
rapidly).
a. Coarse grinding.
b. Low pressing pressure.
c. Small quantity of ground cof-
fee.
d. Water temperature below 90°C.
e. Pump pressure above 9 bar.
f. Sprinkler filter on unit clogged.
g. Filter holes widened (filter cup)
a. Finer grinding.
b. Increase the pressure.
c. Increase the quantity of ground coffee.
d. Increase the pressure in the boiler.
e. Decrease the pump pressure.
f. Check and clean with blind filter or
replace.
g. Check and replace the filter.
Dark cream (the coffee
drips out of the spout).
a. Fine grinding.
b. High pressing pressure.
c. Large quantity of ground coffee.
d. High percolation water tem-
perature.
e. Pump pressure below 9 bar.
f. Sprinkler filter on unit clogged.
g. Filter holes clogged (filter cup)
a. Coarser grinding.
b. Reduce the pressure.
c. Decrease the quantity of ground coffee.
d. Decrease the boiler pressure.
e. Increase the pump pressure.
f. Check and clean with blind filter or
replace.
g. Check and replace the filter.
Presence of grounds in cof-
fee cup
a. Coffee ground too fine.
b. Worn grinders in grinder-dis-
penser unit.
c. Pump pressure above 9 bar.
d. Sprinkler filter on unit clogged.
e. Filter holes widened (filter cup)
a. Coarser grinding.
b. Replace the grinders.
c. Decrease the pump pressure.
d. Check and clean with blind filter or
replace.
e. Check and replace filter
Coffee with too little cream
in cup (spurts out of spout).
Sprinkler filter on unit clogged.Check and clean with blind filter or replace.
The cream in the cup is too
thin (it disappears after a
few seconds).
Coffee extraction takes a long time due to clogged filter.
Coffee extraction too fast due to clogged sprinkler filter.
Water temperature too high.
Clean or replace the filter.
Clean or replace the sprinkler filter.
Lower the temperature in the boiler.
Presence of depressions in
the coffee grounds (looking
inside the filter cup).
Sprinkler filter partly clogged.
Low amount of ground coffee for the fiter used.
Clean or replace the sprinkler filter.
Adjust the amount of ground coffee.

La San Marco 95 SERIES coffee machine troubleshooting

PROBLEMCAUSESOLUTION
The boiler fills with water,
with venting from the
safety valve.
Leak in one of the boiler filler
pipes or in one of the unit circuits
• Check the automatic level circuit
• Check the manual fill button
• Check for leaks from the heat exchanger
Operation of the safety
valve with venting of steam
Increase in boiler pressure to 2-
2.5 bar due to incorrect operation
of the heating system because the
element is constantly energised
Check the pressure switch in the electrical contacts in the
mechanical part and in the tube which links it to the steam
pressure in the boiler
• For machines with electronic temperature control, check all
the system components, such as sensor, triac, control unit,
connecting wires and reset the trimmer if necessary
The machine does not heatThe element is not being supplied
with power, or has burnt out or
there is no mains power
• Check that the mains power is on
• Check that the main switch is not damaged
• Check that the safety thermostat on the heater element has
not tripped
• Check the pressure switch for correct electromechanical
operation
• For machines with electronic temperature control, reset the
trimmer, check the sensor, the triac, the control unit and
the sensor-triac-control unit connecting wires
Water is not coming out of
one unit
• Water circuit blocked
• Failed solenoid valve
• Coffee ground too fine and
maybe amount dispensed too
large for the type of filter used
• Check that the injector, the top circulation tube, the jet and
the solenoid valve are not blocked; for machines with
electronically controlled dispensing, also check the volume
meter and that its cut-off tap is open
• Check the electromechanical components of the solenoid
valve, the control unit to coil connecting wires and the
control unit fuse
• Check the dispensing and grinding settings
The settings for the amount
of coffee dispensed do not
remain as set on one or all
the units
• Malfunction of the dispenser
metering circuit on one or all
units
• Leak at unit solenoid valve
• Programme different settings for each unit
• If the problem persists, replace the meter for the unit
involved
• Replace the solenoid valve
The machine will not accept
programming for unit 1
and therefore copying to
the other units
• Malfunction of the meter for unit
1 or of the electronic control unit
• Check the connection between the meter for unit 1 and the
control unit
• If the connection is satisfactory replace the meter for unit 1
or replace the control unit
Alarm signalled by flashing
of the single strong coffee
LED for the unit used
• The metering signals for the unit
meter have not reached the elec-
tronic control unit
• Meter or corresponding electrical circuit damaged
• Check the electromechanical components of the solenoid
valve, the control unit to coil connecting wires, the
corresponding fuse and the control unit itself
Alarm signalled by flashing
of the double strong coffee
LED of all the units and the
tea unit
• The water level in the boiler has
not been topped up within the set
time
• Automatic level circuit blocked or no water supply
upstream
• Automatic level solenoid valve and corresponding electrical
circuit damaged
Dispensing of one or more
measures to a coffee unit or
the tea unit starts up at
random and on its own
• Loss of normal free travel of one
or more of the pushbuttons due to
a build-up of material on the out-
side or infiltration of water or
steam inside the card
• Clean all the push buttons
• Dry the printed circuit
The machine is switched on
and is heating normally;
the mains power light is on
but none of the electronics
are working
• The electronic control unit is not
being energised or has burnt out
• Check that the switch located above the main switch on
the machine for supply to the electronic control unit is not
tripped (if it is, the green light will be on)
• Check the control unit triac protection fuses
In the case of an electronic
machine, unit 1 or unit 2 are
operating continuously even
though dispensing for these
units has not been selected
• The solenoid valve and pump (or
only the solenoid valve) are being
permanently energised
• Emergency switch tripped
• Relay short-circuited and welded
• In the case of model 95-26, button E plus button 1 or 2 are
depressed
In the case of a semi-auto-
matic machine, one unit is
operating continuously
• Circuit permanently energised• Contact in the ON switch welded or wires incorrectly
connected
Small amounts of steam or
drops of water coming from
the steam tap
• Adjusting screw not adjusted
• Tap washer worn
• If the machine has only recently been installed or if the
washer has recently been replaced, unscrew the adjusting
screw
• If the machine is not new, replace the washer
A whistling noise is heard
after coffee has been de-
livere
• Malfunction of the expansion
valve
• Pump pressure too high
• Replace the seal and the spring in the valve and reset it to
12 bar
• Reset the pump
The filter cup detaches
itself while coffee is being
delivered
• Faulty seal under the filter cup• Replace the seal and carefully clean the seats of the three
attaching points on the filter cup and unit by inserting and
detaching the filter cup several times, cleaning it each time
While coffee is being de-
livered, some spills out,
dripping from the edge of
the filter cup
• Poor seal between the filter cup
seal and the filter cup
• Filter cup seal worn: replace it
• Filters flattened by tapping on hard surfaces: replace
Water leaking from the unit
solenoid valve discharge
• Malfunction of the solenoid valve
• For machines with temperature
stabilisation, poor seal between
the cooling tube and its O-ring
• Check that the solenoid valve piston is free to move correct-
ly inside the rod and that there are no impurities present:
clean or replace
• Check the O-ring inside the cooling chamber and replace if
necessary
Water dripping from the
tea tap
• Tap washer worn
• If manual tap, the adjusting
screw needs adjusting
• If electronic dispensing, solenoid
valve leaking
• As for the steam tap
• Check the solenoid valve and replace if necessary
Light coloured cream (the
coffee comes out of the
spout fast)
• Coffee ground too coarse
• Weak pressing
• Insufficient batch
• Water temperature below 90°C
• Pump pressure higher than 9 bar
• Sprinklers blocked
• Filter holes enlarged
• Grind coffee finer
• Increase the pressing force
• Increase the batch dispensed
• Increase boiler pressure
• Reduce pump pressure
• Check and clean with blind filter
• Check and replace
Dark coloured cream (the
coffee drips out of the
spout)
• Coffee ground too fine
• Excessive pressing
• Batch too large
• Water temperature higher than
90°C
• Pump pressure less than 9 bar
• Sprinklers blocked
• Filter and filter holder clogged
• Grind coffee coarser
• Reduce the pressing force
• Reduce the batch amounts
• Reduce boiler pressure
• Increase pump pressure
• Check and clean with blind filter
• Check and clean
Coffee grounds in the cup• Coffee ground too finely
• Grinders worn
• Pump pressure higher than 9 bar
• Filter holes enlarged
• Sprinklers blocked
• Grind more coarsely
• Replace the grinders
• Reduce pump pressure
• Check or replace
• Clean or replace
Coffee with little cream (comes
out of the spout in spurts)
• Filter cup holes blocked• Clean
Coffee dripping over edge
of filter cup
• Filter cup delivery hole blocked
• Poor sealing of the filter cup seal
• Clean
• Replace
Depressions in the coffee
grounds in the filter cup
• Sprinklers partially blocked• Clean or replace and check filters with relevant dose
Cream does not last long• Prolonged extraction due to
blocked filter
• Fast extraction due to blocked
sprinklers
• Water temperature too high
• Clean or replace the filter
• Clean or replace the sprinklers
• Reduce the boiler pressure