Pioneer QUANTUM INVERTER Series Service & Troubleshooting Manual page 12

2. Pipe Length, Adjustment Charge, and Drop Height
The length and elevation of connection pipe are shown in the table below. If the pipe length exceeds or falls below*
the standard pipe length range, refrigerant should be adjusted to ensure nominal cooling/heating capacity.
Capacity(Btu/h) Standard Length
9k~12k
18k
24k/30k
36k
*Do not use a lineset shorter than 1.5m (5ft).
If oil flows back into the outdoor unit's compressor, this might cause liquid compression or deterioration of oil return.
Oil traps in the rising gas pipe can prevent this.
1. Indoor unit is installed higher than outdoor unit
If indoor unit is installed higher than outdoor unit, oil trap should be set every 10m(32.8ft) of vertical distance.
If the outdoor unit is installed higher than the indoor unit, proper oil should return to the compressor along with the
suction of refrigerant to keep lubrication of compressor. If the suction flow velocity drops below 7.62m/s(1500fpm (ft
per minute)), oil won't return to the compressor. An oil trap should be installed every 6m(20ft) of vertical distance.
Max Pipe Length
25m (82ft)
30m (98.4ft)
≥ 3m (10ft)
≤ 7.5m (25ft)
50m (164ft)
65m (213.3ft)
Specifications

Max Elevation
10m (32.8ft)
20m (65.6ft)
25m (82ft)
30m (98.4ft)
2. Outdoor unit is installed higher than indoor unit
3

Adjustment Refrigerant
15g/m (0.16oz/ft)
30g/m (0.32oz/ft)