882108-YIM-B-1012
Johnson Controls Unitary Products 59
START-UP COMPRESSOR ROTATION
Check for proper compressor rotation (See page 66 for symp-
toms of reverse compressor operations). Millennium units are
properly phased at the factory. If the blower, condenser fan,
or compressor, rotate in the wrong direction at start-up, the
electrical connection to the unit is misphased. Change the
incoming line connection phasing to obtain proper rotation.
SUPPLY AIR FAN INSTRUCTIONS
CHECK BLOWER BEARING SET SCREWS
• The bearing set screws on the supply air blower are
properly torqued before shipment. However, in transit
they may loosen. Prior to start up they should be
rechecked. The set screws are 3/8" and the torque range
is 200 - 215 in.-lbs.
NOTE: If a unit is equipped with exhaust fans, those bear-
ing set screws should also be rechecked. The set
screws are 1/4 inch and the torque range is 70 - 87
in.-lbs.
CHECKING SUPPLY AIR CFM
The RPM of the supply air blower will depend on the required
CFM, the static pressure resistances of the unit components
(Tables 33, 48, 49, 57, and 58) and the static pressure resis-
tances of both the supply and the return air duct systems.
With this information, the RPM for the supply air blower can
be determined from the blower performance data in Tables
30, 31, and 32. See Table 34 for pulley and drive information
for the fixed pitch pulleys supplied on the unit.
The supply air CFM must be within the limitations shown in
Table 2, and Class II fans must be specified where conditions
exceed the rpm limitations of Class I.
NOTE: If unit is equipped with power exhaust fans or return
air fan see Tables 36 and 37 for fan performance
and for pulley and drive information see Table 35.
FAN ROTATION
Check for proper supply air blower rotation. If fans are rotat-
ing backwards the line voltage to unit point of power connec-
tion is misphased (see Compressor Rotation above.) If the
condenser fans are rotating in the correct direction and the
supply fan is not, it will be necessary to switch leads on the
output side of the VFD, since changing phase on the input
side of a VFD does not change rotation on the output side. If
the VFD is equipped with a bypass, verify that rotation is cor-
rect in the bypass mode.
NOTE: If unit is equipped with power exhaust fans or return
air fan also check them for proper rotation.
VFD units with bypass must not have the bypass activated
unless all individual space dampers are full open. It is the
responsibility of the installer to interconnect the bypass mode
to the signal to open all boxes on the circuit.
BELT TENSION
The tension on the belt should be adjusted as shown in Fig-
ure 24 and Table 38.
NOTE: If unit is equipped with power exhaust fans or return
air fan check belt tension and adjust as necessary.
AIR BALANCE
Start the supply air blower motor. Adjust the resistances in
both the supply and the return air duct systems to balance
the air distribution throughout the conditioned space. The job
specifications may require that this balancing be done by
someone other than the equipment installer.
Scroll compressors require proper rotation to oper-
ate correctly. Units are properly phased at the fac-
tory. DO NOT change the internal wiring to make
the blower, condenser fans or compressor rotate
correctly.
FIGURE 24 - BELT TENSION ADJUSTMENT
C A U T IO N
P R O C E D U R E F O R A D J U S T I N G B E L T T E N S I O N
1 . L o o s e n f o u r b o l t s h o l d i n g m o t o r b a s e t o c h a n n e l s
2 . A d j u s t b e l t b y t u r n i n g n u t s " A " ( s e e d e t a i l " B " ) .
3 . U s i n g a b e lt te n s i o n c h e c k e r, a p p l y a p e rp e n d i c u l a r f o r c e
t o o n e b e l t a t t h e m i d p o i n t o f t h e s p a n a s s h o w n . T h e d e f le c ti o n
f o rc e s h o u l d b e a p p li e d u n t il a s p e c i f ic d e f le c t io n d i s t a n c e
o f 1 /6 4 " p e r i n c h o f s p a n le n g t h i s o b ta in e d .
4 . T o d e t e r m i n e t h e d e f le c t io n d i s t a n c e f r o m n o r m a l p o s it io n ,
u s e a s tr a ig h t e d g e fr o m s h e a v e t o s h e a v e a s a re f e r e n c e l in e .
U s e th e r e c o m m e n d e d d e fl e c ti o n f o rc e p e r B e l t A d j u s tm e n t T a b l e .
5 . A f te r a d j u s ti n g , r e t i g h t e n b o lt s h o ld in g m o t o r b a s e t o c h a n n e l .
T e n s i o n n e w b e lt s a t th e m a x im u m d e f l e c t i o n f o r c e
re c o m m e n d e d . C h e c k t h e b e l t t e n s io n a t le a s t t w o ti m e s
d u r i n g t h e fi r s t 2 4 h r s . o f o p e r a t i o n . A n y r e - t e n s io n i n g
s h o u l d fa ll b e tw e e n t h e m i n . a n d m a x . d e f l e c ti o n fo r c e v a lu e s .
"A "
M O T O R B A S E
D E T A IL " B "
S P A N L E N G T H
D E F L E C T IO N
F O R C E