Fujitsu Airstage J-II Series Design & Technical Manual page 579

„ CAUTION
„
Keep the "piping limitation" for correct operation.
z Allowable height difference:
„
If the height difference between the indoor unit and outdoor unit is larger than the allowable value:
¾ The pressure loss will be larger → Insufficient cooling and heating
„
¾ The refrigerant in liquid pipe will flush → Refrigerant flow noise generate at indoor unit
„
¾ The refrigerant oil will not return → Insufficient refrigerant oil resulting in compressor damage
„
If the height difference between indoor unit is larger than the allowable value:
¾ The refrigerant flow balance will be poor → Insufficient cooling and heating (poor balance)
„
¾ Refrigerant oil will collect in the piping or non-operating indoor units
„
z Pipe length:
„
If the pipe length is longer than prescribed:
¾ The pressure loss will be larger → Insufficient cooling and heating
„
¾ Too much refrigerant will be charged → Liquid backs up resulting in compressor damage
„
¾ The refrigerant oil will not return → Insufficient refrigerant oil resulting in compressor damage
„
z Pipe size:
„
If the pipe size is larger than designated size:
¾ The refrigerant flow velocity will drop. Refrigerant oil will not return to the outdoor unit.
„
¾ The refrigerant in liquid pipe will flush easily → Insufficient cooling and heating
„
If the pipe size is smaller than designated size:
¾ The refrigerant circulation volume will drop → Insufficient cooling and heating
„
¾ The pressure loss will be larger → Insufficient cooling and heating
„
z Indoor unit connected capacity:
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If the indoor unit connected capacity is larger than the system capable capacity:
¾ Insufficient system performance → Insufficient cooling and heating
„
¾ When heating, refrigerant will collect in non-operating indoor units resulting in an insufficient
„
refrigerant circulation volume → Insufficient cooling and heating
¾ The refrigerant oil will not return → Compressor damage
„
If the indoor unit connected capacity is too small compared to the system capacity:
¾ The liquid return will be too great → Compressor damage
„
¾ The refrigerant will concentrate in the operating unit
„
→ Continuous operation will become difficult due to triggering of the protection in response
to the pressure high-rise, etc., and noise will be generated by the refrigerant flow when heating
→ Insufficient refrigerant oil resulting in compressor damage
→ Insufficient refrigerant oil resulting in compressor damage
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