Piping Limitation - Fujitsu AJ 126LELDH Series Design & Technical Manual

2-2. Piping limitation

For proper system operation, keep all the piping limitation mentioned here.
CAUTION
• Allowable height difference:
– If the height difference between indoor unit and outdoor unit is larger than the allowable value:
• The pressure loss will be larger. → Insufficient cooling and heating
• The refrigerant in liquid pipe will flush. → Refrigerant flow noise generate at indoor unit
• The refrigerant oil will not return.
→ Insufficient refrigerant oil resulting in compressor damage
– If the height difference between indoor units is larger than the allowable value:
• The refrigerant flow balance will be poor. → Insufficient cooling and heating (poor balance)
• Refrigerant oil will collect in the piping or non-operating indoor units.
→ Insufficient refrigerant oil resulting in compressor damage
• Piping length:
If the piping length is longer than prescribed:
– The pressure loss will be larger. → Insufficient cooling and heating
– Too much refrigerant will be charged. → Liquid backs up resulting in compressor damage
– The refrigerant oil will not return. → Insufficient refrigerant oil resulting in compressor damage
• Pipe size:
– If the pipe size is larger than designated size:
• The refrigerant flow velocity will drop. Refrigerant oil will not return to the outdoor unit.
→ Insufficient refrigerant oil resulting in compressor damage
• The refrigerant in liquid pipe will flush easily. → Insufficient cooling and heating
– If the pipe size is smaller than designated size:
• The refrigerant circulation volume will drop. → Insufficient cooling and heating
• The pressure loss will be larger. → Insufficient cooling and heating
• Indoor unit connected capacity:
– If the indoor unit connected capacity is larger than the system capacity:
• Insufficient system performance. → Insufficient cooling and heating
• When heating, refrigerant will collect in non-operating indoor units resulting in an insufficient
refrigerant circulation volume. → Insufficient cooling and heating
• The refrigerant oil will not return. → Compressor damage
– If the indoor unit connected capacity is too small compared to the system capacity:
• The liquid return will be too great. → Compressor damage
• The refrigerant will concentrate in the outdoor unit.
→ Continuous operation will become difficult due to the outdoor unit stopping due to high
head pressure. Also, excessive noise will be generated by the refrigerant flow when in heat-
ing mode.
2-2. Piping limitation
- (06-17) -
2. Piping design