20
2.6. Condensate Pump Lift - MMDB and
M22A/M33C
MMDB, M22A and M33C factory pumps have a 27 inch
condensate pump lift.
2.7. MMDB Condensate Drain Test
Procedure
CAUTION
Make sure that drain piping is properly routed and insu
-
lated in order to prevent both leaks and condensation.
IMPORTANT
Drain should have a slope of at least ¼ inch per foot and
should be approved corrosion-resistant pipe. You must
confirm operation of every drain and pump in the system
as part of the commissioning procedure.
1.
Use a field-provided hose clamp to secure the drain line
stub on the side of the unit chassis to a field-supplied 1”
(25 mm) drain line. See figure below.
NOTE:
Take care not to over-tighten the hose clamps this
may damage the drain line stub.
INSULATION
INDOOR
UNIT
CONDENSATE
LINE STUB
HOSE CLAMP
FLEXIBLE DRAIN
CONNECTOR
PVC DRAIN
PIPE
Figure 6. Condensate Piping Connection
2.
Make a water-tight connection between the field-provided
condensate drain line and the flexible condensate
connector. Use 1-1/2” OD / 1-1/4” ID PVC pipe for the
drain line.
3.
See figure for applications including an indoor unit using
the internal drain pump.
4.
In all cases, drain should be as short as possible and
should not have any droops or kinks that would restrict
condensate flow and shall be constructed using an
approved pipe. There must be a 2-inch (51 mm) space
between the end of the condensate drain and the final
termination point (ground, open drain, etc.) to ensure that
the line will drain freely.
SUSPENSION RODS
DRAIN LINE
STRUCTURAL CEILING
8 in.
(203 mm)
Max. 28 in
.
SUPPORT
STRAPS
3 ft. (1 m)
Figure 7. Condensate Drain with Pump
5.
After system installation is complete, the condensate
drain line must be checked for leaks and the condensate
pumps must be checked to ensure proper operation. This
check is part of the start-up process which must be done
by the installing contractor. Turn the condensate drain pan
test cover latch counterclockwise to open the cover and
access the drain pan. See figure below. Funnel enough
water to engage the pump into the drain pan through a
flexible tube.
6.
Operate the system in the cooling mode. If the internal
pump is being used, ensure that the pump is operating
and the water in the pan is draining freely. If the internal
pump is not being used, pour the water into the drain pan
and confirm that it has flowed freely out of the pan and
out of the drain termination. If a leak is found, shut down
power to the unit at once and do not restore power to the
unit until the problem has been resolved.
7. Return the test cover and turn the latch clockwise to re-
lock it.
DRAIN PAN
TEST COVER
FUNNEL WATER INTO
PAN THROUGH TUBE
FOR TEST
COVER LATCH
(Turn latch
counterclockwise
to unlock)
CLO
SEDOPEN
CLOSE
D OPEN
NOTE: If using the gravity drain on the MMD unit,
make sure you install the black plug into the clear
pump drain connection to prevent water from
discharging if the gravity drain becomes restricted.
Gravity drain with black plug installed.
Figure 8. Condensate Drain Test
