Troubleshooting Guide

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 Max Pipe Length Max Elevation Adjustment Refrigerant
9k~12k
≤ 7.5m (25ft)
≥ 3m (10ft)
25m (82ft) 10m (32.8ft)
15g/m (0.16oz/ft)
18k 30m (98.4ft) 20m (65.6ft)
30g/m (0.32oz/ft)
24k/30k 50m (164ft) 25m (82ft)
36k 65m (213.3ft) 30m (98.4ft)
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 2. Outdoor unit is installed higher than indoor 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.
 Specifications 3 
*Do not use a lineset shorter than 1.5m (5ft).