Lennox Mini-Split Service Manual / Page 111
Condensate Piping Requirements - MMDA & M22A/M33A
CAUTION
!
Make sure that drain piping is properly routed and
insulated to prevent both leaks and condensation.
Follow these instructions exactly to ensure proper
drainage and unit operation.
1. Use a fi eld-provided hose clamp to secure the drain
line stub on the side of the unit chassis to a fi eld-
supplied 1” (25 mm) drain line. See fi gure 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
Condensate Drain Connection
1. Make a water-tight connection between the fi eld-
provided condensate drain line and the fl exible
condensate connector. Use 1-1/2” OD / 1-1/4” ID
PVC pipe for the drain line.
2. See fi gure for applications including an indoor unit
using the internal drain pump.
3. In all cases, drain should be as short as possible
and should not have any droops or kinks that
would restrict condensate fl ow 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 fi nal termination
point (ground, open drain, etc.) to ensure that
the line will drain freely.
4. 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 fi gure below. Funnel enough
water to engage the pump into the drain pan
through a fl exible tube.
5. 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 confi rm that it has
fl owed 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.
6. Return the test cover and turn the latch clockwise
to re-lock it.
SUSPENSION RODS
DRAIN LINE
STRUCTURAL CEILING
8 in.
(203 mm)
Max. 27-1/2 n.
SUPPORT
STRAPS
3 ft. (1 m)
Condensate Drain with Pump
DRAIN PAN
TEST COVER
FUNNEL WATER INTO
PAN THROUGH TUBE
FOR TEST
COVER LATCH
(Turn latch
counterclockwise
to unlock)
CL
OSE
D
O
PE
N
CLOS
E
D
O
PE
N
Condensate Drain Test
Size
(Btuh)
Condensate Connections
All
1” (25 mm)
Condensate Piping Connections Table
MMDA
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