E/0204/39/58
17.1 PREVENTIVE MAINTENANCE SCHEDULE
Two monthly: Check that the unit's condensate drainage system is perfectly clear and operational.
Yearly:
Check that the fans do not show signs of overheating or abnormal vibrations.
Check that the exchangers are efficient and not soiled.
Note: If the air conditioner works in exceptionally dirty environments or if experience shows that it
requires more frequent maintenance then this maintenance must be performed as required.
Note: After each scheduled and unscheduled service:
check that the condensate drainage system is perfectly efficient.
17.2 EXTRAORDINARY MAINTENANCE INTERVALS
Every 3 years or every 10,000 operating hours the unit must undergo a general overhaul either at
the manufacturer's factory or at companies authorized by STULZ or by qualified agencies at the
customer's own expense.
17.3 REPLACEMENT OF PARTS
To guarantee continuity of service to the units, it is recommended to replace some components
according to their MTBF (medium time before failure).
You can find the MTBF of the most critical components in the following table:
COMPRESSOR:
30,000 operating hours
CONDENSER FAN:
35,000 operating hours
EVAPORATOR FAN:
40,000 operating hours
MECHANICAL THERMOSTAT:
100,000 cycles
COMPRESSOR RELAY:
200,000 cycles
NOTE: the MTBFs in the table above are referred to the time during which the components are
operating. The ratio between this time and the total time of service depends on the type of application,
except for the evaporator fan (operating time is 100% of total service time).
Example:
If you esteem that the compressor will be operating 60% of the total time, the MTBF will be 30,000
working hours / 0.6 = 50,000 hours.
17.4 HOW TO CLEAN THE UNIT
Do not use acid or caustic substances to clean
any part of the air conditioner.
To clean the condenser blow compressed air in
the direction opposite to the normal air flow
direction through the heat exchanger. For a better
access to the condenser coil, remove the panel
of the condenser fan and rinse compressed air
closer to the coil.
The inner parts of the cooling unit, either on the
room or shelter side, must be cleaned with a li-
quid detergent and compressed air having a
pressure not higher than 4 bar, with the unit
properly earthed.
Cleaning the condenser
