Fujitsu AUYG18LVLB Design & Technical Manual page 188

2-2. Piping limitation
CAUTION
Keep the "piping limitation" for correct operation.
• 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
The refrigerant in liquid pipe will flush
The refrigerant oil will not return
– If the height difference between indoor units is larger than the allowable value:
The refrigerant flow balance will be poor
Refrigerant oil will collect in the piping or
non-operating indoor units
• Piping length:
If the piping length is longer than prescribed:
The pressure loss will be larger
Too much refrigerant will be charged
The refrigerant oil will not return
• Pipe size:
– If the pipe size is larger than designated size:
The refrigerant flow velocity will drop. Re-
frigerant oil will not return to the outdoor
unit.
The refrigerant in liquid pipe will flush easi-
ly
– If the pipe size is smaller than designated size:
The refrigerant circulation volume will drop
The pressure loss will be larger
2-2. Piping limitation
→ Insufficient cooling and heating
Refrigerant flow noise generate at indoor
→
unit
Insufficient refrigerant oil resulting in com-
→
pressor damage
Insufficient cooling and heating (poor bal-
→
ance)
Insufficient refrigerant oil resulting in com-
→
pressor damage
→ Insufficient cooling and heating
Liquid backs up resulting in compressor
→
damage
Insufficient refrigerant oil resulting in com-
→
pressor damage
Insufficient refrigerant oil resulting in com-
→
pressor damage
→ Insufficient cooling and heating
→ Insufficient cooling and heating
→ Insufficient cooling and heating
- 180 -
2. Pipe design