Lennox VRF VMDB Series Installation Instruction page 7

Unit Installation Instructions
1. Make sure that the structural ceiling or slab is able
to support the weight of the indoor unit. It may be
necessary to add extra support.
2. Install suspension
ceiling or concrete slab in a suitable location.
If the structural ceiling is constructed of concrete,
install anchors to accept four ⅜" threaded rods to
suspend the indoor unit. If the structural ceiling
includes wooden joists, use angle iron or Unistrut
channel fixed securely in place to accept the ⅜"
threaded rods. NOTE - Threaded rod (requirement
of Lennox warranty program) is the ONLY acceptable
method of suspending the unit; do not use chains or
straps. See Figure 2.
CONCRETE CEILING
USING ANCHORS
ANCHOR
ANGLE IRON
BOLTED IN
⅜" THREADED
PLACE ACROSS
WOODEN JOISTS
Figure 2. Suspending Methods
3. Slide one nut and one washer onto each threaded rod.
Use electrical tape to keep the washer from failing off.
Position the nuts slightly above the final resting place
of the four suspension brackets. See Figure 3.
⅜" THREADED
INDOOR UNIT
SUPPLY AIR
OPENING
FRONT VIEW
Figure 3. Suspension Hardware
rods in the structural
⅜" THREADED
ROD
ANGLE IRON
ACROSS
ROD
WOODEN JOISTS
WOODEN JOIST
When unit is
ROD level, tighten
nut to secure
position of
suspension
bracket on
rod.
LEVELING
NUT
SUSPENSION
BRACKET
4. Use either a mechanical lifting device or a minimum
of two people to raise the unit and insert the threaded
rods into the suspension brackets on the cassette
base. Slide a washer and then a nut onto each rod
below each suspension bracket. Use the leveling nut
(beneath suspension bracket) to adjust the unit to the
correct height. Remove the electrical tape holding the
upper washers and nuts in place and tighten each
of the four nuts above the brackets down onto the
brackets. This will ensure that the unit remains level.
5. It is recommended to install a field-provided isolation
grommet as shown in Figure 4 to prevent transmission
of vibration from unit to structural ceiling.
⅜" THREADED
ROD
FIELD-PROVIDED
ISOLATION GROMMET
WASHER
LEVELING
NUT
Figure 4. Isolation Grommet
6. If the unit is being installed in an application that includes
a sheet rock (plasterboard) ceiling, it is required that
an access panel be installed in a suitable location.
This will also allow access for future maintenance
(requirement of
Access is required during the commissioning process
to test the condensate disposal system (See Figure
20) and to check the local disconnect.
7. The unit is factory-configured for the supply air to be
delivered from the front and the return air filter at the
rear of the unit. The return air filter location can be
relocated in the field for bottom return air filter access,
if more convenient. See Figure 10.
7
SUSPENSION
BRACKET
Lennox warranty program).