Changing Fan Wheel Speed By Changing Pulleys; Condenser Coil Service; Round Tube Plate Fin (Rtpf) Condenser Coil; Recommended Condenser Coil Maintenance And Cleaning - Bryant Preferred Series Service And Maintenance Instructions

21. Do not tighten the mounting bolts at this time.
22. Set new motor and motor mounting bracket back onto the
unit. See Fig. 9.
23. Install four bolts, four flat washers, four new lock washers
and four nuts attaching the motor assembly to the unit.
24. Do not tighten the mounting bolts at this time.
25. Install motor drive V-belt to motor pulley and blower
wheel pulley. See CAUTION.
26. Align the motor pulley and blower wheel pulley using a
straight edge. See Fig. 6.
27. Adjust the V-belt tension using adjustment tool.
28. Turn two jack bolts clockwise, moving the motor assembly
away from the blower pulley, increasing the V-belt tension.
29. Tighten the four bolts securing the motor mounting brack-
ets to the unit. Torque four bolts to 120 ± 12 in.-lb (14 ±
1.4 Nm).
30. Remove cover on motor connection box.
31. Re-connect all electrical leads to the motor and replace the
connection box cover.
32. Re-connect all electrical power to the unit. Remove lock-
out tags on all electrical power sources.
33. Start unit and allow to run for a designated period.
34. Shut off unit and make any necessary adjustments to the V-
belt tension or the motor and blower wheel pulley alignment.
BELT
DEFLECTION
Fig. 10 — Adjusting V-belt Tension

Changing Fan Wheel Speed by Changing Pulleys

The horsepower rating of the belt is primarily dictated by the pitch
diameter of the smaller pulley in the drive system (typically the
motor pulley in these units). Do not install a replacement motor
pulley with a smaller pitch diameter than provided on the original
factory pulley. Change fan wheel speed by changing the fixed fan
pulley (larger pitch diameter to reduce wheel speed, smaller pitch
diameter to increase wheel speed) or select a new system with
both pulleys and matching belt(s).
Before changing pulleys to increase fan wheel speed, check the
fan performance at the target speed and airflow rate to determine
new motor loading (bhp). Use the fan performance tables or use
the Packaged Rooftop Builder software program. Confirm that the
motor in this unit is capable of operating at the new operating con-
dition. Fan shaft loading increases dramatically as wheel speed is
increased.
CAUTION
EQUIPMENT DAMAGE HAZARD
Failure to follow this caution can result in equipment damage.
Drive packages cannot be changed in the field. For example: a
standard drive cannot be changed to a high static drive. This
type of change will alter the unit's certification and could re-
quire heavier wiring to support the higher amperage draw of
the drive package.
STRAIGHTEDGE
BROWNING BELT
TENSION CHECKER
1/2"
(1.3 cm)
To reduce vibration, replace the motor's adjustable pitch pulley
with a fixed pitch pulley (after the final airflow balance adjust-
ment). This will reduce the amount of vibration generated by the
motor/belt-drive system.
To determine variable pitch pulley diameter, perform the follow-
ing calculation:
1. Determine full open and full closed pulley diameter.
2. Subtract the full open diameter from the full closed diameter.
3. Divide that number by the number of pulley turns open
from full closed.
This number is the change in pitch datum per turn open.
EXAMPLE
• Pulley dimensions 2.9 to 3.9-in. (full close to full open)
• 3.9 – 2.9 = 1-in.
• 1 divided by 5 (turns from full close to full open)
• 0.2 change in pulley diameter per turn open
• 2.9 + 0.2 = 3.1-in. pulley diameter when pulley closed one
turn from full open

CONDENSER COIL SERVICE

Round Tube Plate Fin (RTPF) Condenser Coil

The condenser coil is fabricated with round copper hairpins tubing
and plate fins of various materials and coatings (see Appendix A
to identify the materials provided in this unit). The coil can be one-
row or composite-type two-row. Composite two-row coils are two
single-row coils fabricated with a single return bend end
tubesheet.
Recommended Condenser Coil Maintenance and
Cleaning
Routine cleaning of coil surfaces is essential to maintain proper
operation of the unit. Elimination of contamination and removal of
harmful residues will greatly increase the life of the coil and ex-
tend the life of the unit. The following maintenance and cleaning
procedures are recommended as part of the routine maintenance
activities to extend the life of the coil.
REMOVE SURFACE LOADED FIBERS
Surface loaded fibers or dirt should be removed with a vacuum
cleaner. If a vacuum cleaner is not available, a soft non-metallic
bristle brush can be used. In either case, the tool should be applied
in the direction of the fins. Coil surfaces can be easily damaged
(fin edges can be easily bent over and damage to the coating of a
protected coil) if the tool is applied across the fins.
NOTE: Use of a water stream, such as a garden hose, against a
surface loaded coil will drive the fibers and dirt into the coil. This
will make cleaning efforts more difficult. Surface loaded fibers
must be completely removed prior to using low velocity clean wa-
ter rinse.
PERIODIC CLEAN WATER RINSE
A periodic clean water rinse is very beneficial for coils that are ap-
plied in coastal or industrial environments. However, it is very im-
portant that the water rinse is made with a very low velocity water
stream to avoid damaging the fin edges. Monthly cleaning, as de-
scribed below, is recommended.
ROUTINE CLEANING OF COIL SURFACES
Periodic cleaning with Totaline
cleaner, is essential to extend the life of coils. This cleaner is avail-
able from Replacement Components Division as part number
P902-0301 for a one gallon container, and part number P902-0305
for a 5 gallon container. It is recommended that all coils, including
standard aluminum, pre-coated, copper/copper or E-coated coils,
be cleaned with the Totaline environmentally sound coil cleaner as
described below. Coil cleaning should be part of the unit's regular-
ly scheduled maintenance procedures to ensure long life of the
7
® , environmentally sound coil