Heat Pump Refrigeration System - Carrier 50TCQD17-D24 Service And Maintenance Instructions

Bearings:
The fan system uses bearings featuring concentric split
locking collars. A Torx T25 socket head cap screw is used
to tighten the locking collars. Tighten the locking collar
by holding it firmly against the inner race of the bearing
and tightening the socket head cap screw. Torque the
socket head cap screw 55 - - 60 in- - lb (6.2 - - 6.8 Nm).
See Fig. 8.
Fig. 8 - - Tightening Locking Collar
Motor
Always replace the external- - tooth lock washer (star
washer) under the motor mounting base; this is part of the
motor grounding system. Ensure the teeth on the lock
washer are in contact with the motor's painted base.
Tighten motor mounting bolts and torque to 120 12
in- - lbs (14  1.4 Nm).
Change fan wheel speed by changing the fan pulley
(larger pitch diameter to reduce wheel speed, smaller
pitch diameter to increase wheel speed) or select a new
system (both pulleys and matching belt). 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 was provided on the original factory pulley.
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 condition. Fan
shaft loading increases dramatically as wheel speed is
increased.
To reduce vibration, replace the motor's adjustable pitch
pulley with a fixed pitch pulley (after the final airflow
balance adjustment). This will reduce the amount of
vibration generated by the motor/belt- - drive system.
LOCKING COLLAR
T-25 TORX SOCKET
HEAD CAP SCREW
C11505
HEAT PUMP REFRIGERATION
SYSTEM
WARNING
!
UNIT OPERATION AND SAFETY HAZARD
Failure to follow this warning could cause personal
injury, death and/or equipment damage.
This system uses Puron
operates at higher pressures than standard R- - 22
systems and other refrigerants. No other refrigerant
can be used in this system. Gauge set, hoses, and
recovery system must be designed to handle Puron
refrigerant. If unsure about equipment, consult the
equipment manufacturer.
Outdoor Coil
The 50TCQ outdoor coil is fabricated with round tube
copper hairpins and plate fins of various materials and/or
coatings (see "Appendix I - - Model Number Significance"
to identify the materials provided in this unit). All unit
sizes use composite- - type two- - row coils. Composite
two- - row coils are two single- - row coils fabricated with a
single return bend end tubesheet.
Indoor Coil
The indoor coil is traditional round- - tube, plate- - fin
technology. Tube and fin construction is of various
optional materials and coatings (see Model Number
Format). Coils are multiple- - row.
Recommended Outdoor Coil Maintenance
and Cleaning
Routine cleaning of coil surfaces is essential in
maintaining proper operation of the unit. Elimination of
contamination and removal of harmful residues will
greatly increase the life of the coil and extend 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 the coating of a protected coil)
when 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 and dirt must be
completely removed prior to using low velocity clean
water rinse.
6
R
(R410A) refrigerant that