Internal Vibration Isolation; External Vibration Isolation; Roof Curb - Carrier AERO 39MN Installation, Start-Up And Service Instructions Manual

Fig. 6 — Lifting Lug Detail for Pad-Mounted Unit
with or without Isolation
Internal Vibration Isolation —
internal vibration isolation must be prepared as described in
this section before they are installed.
For applications that do not require internal fan isolation,
leave the holddown bracket screwed or bolted in place. Oth-
erwise, the combination of internal and external unit isolation
could lead to unwanted oscillation magnification.
REMOVING HOLDDOWN BOLTS, AIRFOIL, PLENUM
AND FORWARD-CURVED FANS — Remove
down bolts (Fig. 7) as follows:
1. Open the fan access door.
2. Remove the bolts that fasten the fan sled to the hold-
down bracket (Fig. 7). Remove "S" shaped brackets.
3. Repeat Steps 1 and 2 on the opposite side of the fan
section. Fan sled assembly should float on isolator
springs when done.
ADJUSTING STEM
"S" SHAPED
BRACKET
HOLDDOWN
BOLT
a39-4049
SPRING
Fig. 7 — Spring Isolator and Holddown Bracket
ADJUSTING ISOLATOR SPRINGS — Units with factory-
supplied motors and drives are preset to
ance between the base frame assembly and the bottom pan-
els; field adjustment of the isolator springs is not normally
required.
WARNING
When adjusting fan isolation components, DO NOT enter
or reach into the fan cabinet while fan is running. Serious
injury can result. Be sure to disconnect power and tag
controls before making adjustments.
a39-4329
Units equipped with
the hold-
SLED MEMBER
HOLDDOWN
BOLT
"S" SHAPED BRACKET
13 / + 1 / -in. clear-
16 8
When field-supplied motors and drives have been in-
stalled, adjust the isolator springs as shown in Fig. 7 and de-
scribed as follows:
1. Loosen the locknut on adjusting stem.
2. Turn the adjusting stem until the specified clearance of
13 / + 1 / -in. is obtained. (Turn clockwise to decrease
16 8
clearance or counterclockwise to increase clearance.)
3. Tighten the locknut.
4. Repeat for each of the isolator springs and ensure that
the fan sled is floating on the springs.
External Vibration Isolation —
tion isolators per certified drawings, job specifications, and
the instructions of the isolator manufacturer.
For applications that do not require internal fan isolation,
leave the holddown bracket screwed or bolted in place. Oth-
erwise, the combination of internal and external unit isolation
could lead to unwanted oscillation magnification.
The coil piping must also be isolated or have flexible con-
nectors to avoid coil header damage due to motion or vibra-
tion. Flexible connections should also be installed at the fan
inlet (if ducted) and at the discharge.
Roof curbs can be factory or field supplied
Roof Curb —
for 39MW units and should be installed according to the
manufacturer's instructions.
Before installing roof curb, check overall unit length. Figure
8 shows AHU (air-handling unit) curb pocket dimensions.
1.00
3.00
4.50
2.25
1.00
NOTE: All dimensions are shown in inches.
Fig. 8 — Curb Pocket Dimensions
(Sizes 03-110 Typical)
Curbs are typically shipped knocked down and require
field assembly as follows:
1. Curbs greater than 12 ft in airway length will be split
and joined together by a splice plate. Butt the two sec-
tions and bolt together with the splice plate as shown in
Fig. 9.
2. Arrange sides and ends together at right angles and bolt
together using the corner bracket as shown in Fig. 10.
3. Fasten cross supports, when required, per the drawings
with supplied screws as shown in Fig. 11.
46
Install external vibra-
1.893
1.00
1.221
Ø1.50
1.74
2X Ø 0.625
a39-4144
1.893
3.00
6.00