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 leak.Check 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 heating 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 program 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 position 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 electronic 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 coffee.
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 temperature.
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 coffee cup.a. Coffee ground too fine.
b. Worn grinders in grinder-dispenser 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 steamIncrease in boiler pressure to 2-2.5 bar due to incorrect operation of the heating system because the element is constantly energisedCheck 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 heat The 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 electronic 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 outside 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-automatic 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 delivere• 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 delivered, 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 correctly 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