Lennox VRF VMDB Series Installation Instruction page 12

Condensate Piping Connections
CAUTION
Make sure that drain piping is properly routed and
insulated in order to prevent both leaks and condensation.
Follow these instructions exactly to ensure proper
drainage and unit operation.
1. Use the provided hose clamp to secure the provided
flexible condensate drain connector and insulating
sleeve to the drain line stub on the side of the indoor
unit. See Figure 16. NOTE - Take care not to over-
tighten the hose clamps this may damage the drain
line stub.
LIFT PUMP
CONNECTION
GRAVITY
DRAIN
CONNECTION
FLEXIBLE DRAIN
INDOOR
UNIT
CONDENSATE HOSE CLAMP
LINE STUB
Figure 16. Condensate Drain Connection
2. Make a water-tight connection between the field-
provided condensate drain line and the flexible
condensate connector. Unit connection is 1 in. O.D.
Use 1" I.D. PVC pipe for the drain line. NOTE - copper
drains are suitable for use within plenum rated ceilings.
3. See Figure 17 for applications including a single unit
and a single gravity drain. In this case, ensure that
the drain line is properly sloped (no less than 1/4
inch per foot) and condensate lines are routed to
ensure moisture is drained away from the indoor unit.
A gravity drain connection port is located on the
side of the unit with the refrigerant piping and on the
opposite side of the unit. Select one connection to
use and leave the unused connection port sealed.
Seal and plug the lift pump connection port
when using either gravity drain connection port.
Disconnect the factory-installed lift pump, CN 13.
PVC DRAIN
CONNECTOR
PIPE
INSULATION
4. See Figure 18 for applications including a single unit
using the internal drain pump.
You must confirm operation of every drain and pump in
the system as part of the commissioning procedure.
Structural Ceiling
Suspension Rods
Indoor Unit
Do not overtighten drain fitting.
Do not operate unit without condensate drain trap.
NOTE - Drain line should be sloped 1/4 inch per foot (18 mm per m)
AWAY from unit and should be supported as needed to prevent sagging.
Figure 17. Sloped Condensate Gravity Drain
STRUCTURAL CEILING
SUSPENSION RODS
Figure 18. Condensate Drain with Lift Pump
5. See Figure 19 for applications including multiple units
using the internal pump to provide lift into a single,
correctly sized main drain. In this case, ensure that
the main drain line is properly sloped, no less than
1/4 inch per foot (6 mm per 305 mm), and that each
individual drain is connected to the main drain exactly
as shown.
6. 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.
12
IMPORTANT
Anti-siphon vent must extend above the
height of the coil drain pan by 2" (51 mm).
1 ft.
(305 mm) max
Clean Out
Do not glue
3"
3"
Single Unit
8 in.
3 ft. (1 m)
(203 mm)
SUPPORT
STRAPS
DRAIN LINE
Single Unit
3 ft.
(1 m)
Support
straps
Drain line