Carrier 38QUA009DS, Service Manual, Page: 75 / 116

72
Attention: Adopt PVC40 or bigger pipe to be the
main pipe.
For Vertical drainage pipe (The following
table is for reference)
PVC
pipe
Reference
value
of
inner
diameter of
pipe (mm)
Allowable
maximum
water
flowrate (l/h)
Remark
PVC25 20 220
For branch
pipe
PVC32 25 410
PVC40 31 730
Could be used
for confluence
pipe
PVC50 40 1440
PVC63 51 2760
PVC75 67 5710
PVC90 77 8280
Attention: Adopt PVC40 or bigger pipe to be the
main pipe.
3. Individual design of drainage pipe
system

The drainage pipe of air conditioner shall
be installed separately with other sewage
pipe, rainwater pipe and drainage pipe in
building.

The drainage pipe of the indoor unit with
water pump should be apart from the one
without water pump.
4. Supporter gap of drainage pipe

In general, the supporter gap of the
drainage pipe horizontal pipe and vertical
pipe is respectively 1m~1.5m (3.28~4.92ft)
and 1.5m~2.0m(4.95~6.56ft).

Each vertical pipe shall be equipped with
not less than two hangers.

Overlarge hanger gap for horizontal pipe
shall create bending, thus leading to air
block.
Too long distance
Gas bag
5. The horizontal pipe layout should avoid
converse flow or bad flow
Drainage pipe
Water flow
Drainage pipe
Drainage pipe
Drain tee
Drain tee
Water flow Water flow
Water flow
Water flow
Water flow
Water flow
Water flow Water flow
Drain tee
Branch pipe
Water flow
Water flow
Keep a certain degree
Branch pipe
Gas Gas
Main pipe
Main pipe

The correct installation will not cause
converse water flow and the slope of the
branch pipes can be adjusted freely

The false installation will cause converse
water flow and the slope of the branch pipe
cannot be adjusted.
6. Water storage pipe setting

If the indoor unit has high extra static
pressure and without water pump to
elevate the condensate water, such as high
extra static pressure duct unit , the water
storage pipe should be set to avoid
converse flow or blow water phenomena.
Indoor unit
More than 50mm
More than 25mm
Plug
Water storage pipe
7. Lifting pipe setting of indoor unit with
water pump

The length of lifting pipe should not exceed
the pump head of indoor unit water pump.

The drainage pipe should be set down
inclined after the lifting pipe immediately to
avoid wrong operation of water level switch.

Refer the following picture for installation
reference.