Hitachi FSXN Series Service Manual page 353

12 Maintenance notes
12.4 Not cooling well due to insufficient installation space for the outdoor unit
Question and answer for the field work
Example: Not cooling well due to insufficient installation space for outdoor unit
Cooling operation was well performed through the intermediate season. However, the cooling operation was not well available
Phenomenon
when the outdoor temperature was higher than 35 °C.
As the outdoor units were installed without a sufficient installation space, the hot discharge air from other outdoor units was
circulated.
In this case, though the outdoor temperature was 35 °C, the actual suction air temperature was nearly 50 °C and the protection
system for excessively high suction pressure was activated, the frequency of the compressor was decreased and the cooling
capacity was also decreased accordingly.
As the outdoor units in-line were installed back to back with a distance of 600 mm between each outdoor unit's back, the hot
discharged air from other outdoor units was circulated.
Cause
Countermeasure To protect the unit from a short circuit, fences were mounted at the discharge air side as shown.
351
SMGB0065 rev. 1 - 12/2010
Min. 300 mm
Fence
Min. 300 mm
12