Internal Vibration Isolation; Removing Holddown Bolts, Airfoil; Adjusting Isolator Springs; External Vibration Isolation - Carrier Aero 39MN Series Installation, Start-Up And Service Instructions Manual

Fig. 16 — 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. Other-
wise, the combination of internal and external unit isolation
could lead to unwanted oscillation magnification.
REMOVING HOLDDOWN BOLTS, AIRFOIL, PLENUM
AND FORWARD-CURVED FANS — Remove the hold-
down bolts (Fig. 17) as follows:
1. Open the fan access door.
2. Remove the bolts that fasten the fan sled to the hold-
down bracket (Fig. 17). 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
SPRING
Fig. 17 — Spring Isolator and Holddown Bracket
ADJUSTING ISOLATOR SPRINGS — Units with fac-
tory-supplied motors and drives are preset to
clearance between the base frame assembly and the bottom
panels; field adjustment of the isolator springs is not nor-
mally 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
SLED MEMBER
HOLDDOWN
BOLT
"S" SHAPED BRACKET
13 / + 1 / -in.
16 8
When field-supplied motors and drives have been installed,
adjust the isolator springs as shown in Fig. 17 and described 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 —
bration 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. Other-
wise, 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 vibration.
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 manu-
facturer's instructions. Before installing roof curb, check over-
all unit length. Figure 18 shows AHU (air-handling unit) curb
pocket dimensions.
1.00
1.00
3.00
4.50
2.25
1.00
NOTE: All dimensions are shown in inches.
Fig. 18 — 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 sections
and bolt together with the splice plate as shown in Fig. 19.
2. Arrange sides and ends together at right angles and bolt
together using the corner bracket as shown in Fig. 20.
3. Fasten cross supports, when required, per the drawings
with supplied screws as shown in Fig. 21.
84
Install external vi-
1.893
1.221
Ø1.50
6.00
1.74
2X Ø 0.625
1.893
3.00