Staged Air Volume; Cooling - Bryant 551K 04N Series Service And Maintenance Instructions

5. Line up rectangle key way in the center of stator with rect-
angle feature on motor and set stator onto motor.
6. Install four #10-32 x
(P/N: AD07AB126) to connect aluminum stator to motor.
Tighten to 23 in.-lbs (2.6 Nm).
7. Fit grommet on motor wire harness into keyhole feature on
the side of the stator and pull wire harness out through
grommet.
8. Install rotor on motor by lining up one of 9 holes on com-
posite rotor with one of 9 holes on motor flange. This can
be done by adjusting motor and the top of the motor hub
and aligning using a 3 /
16
fan rotor down until it is flush with the motor flange.
9. Set retaining rings (x3) into composite rotor and install six
#10-32 x 1 / -in.
2
(P/N: AD07AB126) through the holes in retaining rings.
Tighten to 23 in.-lbs (2.6 Nm). It is recommended this
screw installation be done in a star pattern.
10. Align tabs of composite casing with rectangular cutouts on
top of aluminum stator and snap into place.
11. Final assembly should have a small clearance between top of
plastic rotor and underside of casing lip. Spin rotor by hand to
ensure no contact or rubbing between these two parts.
Reinstalling Motor and Fan Assembly
See Fig. 13.
1. Align motor harness/grommet at ~7 o'clock (facing
installer) and align the bottom flats on right and left sides
of fan stator with fan deck ribs. Drop fan assembly down
into fan deck opening and slide back until aluminum stator
is under the rear fan deck brackets.
2. Align (if necessary) two front holes and fasten stator to fan
deck with 2 #10 x 5 / -in. hex head screws (P/N: AL48AM217).
8
Tighten to 50 in.-lb (5.65 Nm).
3. Reconnect wires for stator temperature limit switch.
4. Pull motor harness tight through grommet and plug it in to
the control box harness and secure in the corner with snap-
in wire tie.

Staged Air Volume

All 551K units with Axion™ Fan technology come factory set
to automatically adjust the indoor fan motor speed in sequence
with the unit's ventilation, cooling, and heating operation.
When the first stage of cooling is requested, unit fan will oper-
ate at 75% of the user set full load airflow. When the second
stage of cooling is required, UCB will allow the full design air-
flow rate for the unit (100%). During the heating mode, the
unit will allow total design airflow rate (100%). During venti-
lation mode, the fan will operate at 75% speed.
See Table 1 on page 5 for 2-Pin DIP switch settings.

COOLING

WARNING
UNIT OPERATION AND SAFETY HAZARD
Failure to follow this warning could cause personal injury,
death and/or equipment damage.
This system uses Puron ®
sures than R-22 and other refrigerants. No other refrigerant
may be used in this system. Gage set, hoses, and recovery
system must be designed to handle Puron refrigerant. If un-
sure about equipment, consult the equipment manufacturer.
1 / -in. hex head machine screws
2
-in. Allen key or similar pin. Press
hex head machine
refrigerant which has higher pres-
screws
5
7 7
Fig. 12 — Fan System Re-Assembly
4
2
8
1
3
Fig. 13 — Fan Assembly Install
10
9
8
4
6
3
2
1