Carrier 42QHG009D8S Installation Manual page 20

CAUTION
• Oil traps
If the indoor unit is installed higher than
the outdoor unit:
-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 piping
can prevent this.
An oil trap should be installed every
10m (32.8ft) of vertical suction line riser.
Gas piping
Oil trap
Outdoor unit
The indoor unit is installed higher than the
outdoor unit
Page 18-GB
Indoor unit
10m/32.8ft
Liquid piping
10m/32.8ft
The outdoor unit is installed higher than the
indoor unit
CAUTION
If the outdoor unit is installed higher
than the indoor unit:
-It is recommended that vertical suction
risers not be upsized. Proper oil return
to the compressor should be maintained
with suction gas velocity. If velocities
drop below7.62m/s (1500fpm (feet per
minute)), oil return will be decreased.
An oil trap should be installed every
6m(20ft) of vertical suction line riser.
Gas piping
Oil trap
Indoor unit
Outdoor unit
6m/20ft
Liquid piping
6m/20ft