Hitachi EX1900-5 Operator's Manual page 219

Seasonal Maintenance
--- preseason
--- off-season
CAUTION: Do not attempt to loosen con-
nections in air conditioning circuit when the air
conditioner malfunctions. Doing so may cause
high pressure gas to spout, resulting in serious
injury. Consult your authorized dealer immedi-
ately.
1. Preseason maintenance
Prior to the season, consult your authorized dealer for
maintenance of the air conditioner in order to operate
it in good condition during the season.
This maintenance includes replenishment of refriger-
ant, inspection and replacing (if necessary) of inner
and outer air filters, line connections, pressure
switches and inspection and cleaning of evaporator.
2. Off-season maintenance
(1) Operate the compressor once a week at low speed
for several minutes in order to maintain its parts in
well lubricated condition. Be sure to run the engine
at slow idle and air temperature to MEDIUM COOL.
This operation also prevents refrigerant leakage
caused by a dried up shaft seal.
(2) Check for refrigerant leakage. If the refrigerant
level is low during off-season, rust will form inside
the circuit.
NOTE: Do not remove compressor belt from the com-
pressor during off-season.
MAINTENANCE
7-87