Checking Cooling And Heating Control Operation; Checking And Adjusting Refrigerant Charge; Refrigerant Charge; No Charge - Carrier 50SZ Series Installation, Start-Up And Service Instructions Manual

C
O
R
G
Y
E
W2
THERMOSTAT
AND SUBBASE
Fig. 13—Control Connections
SINGLE-PHASE
L1
CONNECTIONS
TO DISCONNECT
L2
PER NEC
LEGEND
NEC – National Electrical Code
Field Wiring
Splice Connections
Fig. 14—Line Power Connections
24 V Circuit Breaker
24 Volt Compartment
Fig. 15—Control Wiring Plate
when the outdoor temperature is below 40° F (unless accessory
low-ambient kit is installed). Do not rapid-cycle the compressor.
Allow 5 minutes between "on" cycles to prevent compressor
damage.
BRN
ORN
RED
GRN
YEL
WHT
UNIT CONTROL POWER
SPLICE BOX
GROUND SCREW
(IN SPLICE BOX)
GROUND
LEAD
BLK
YEL
NOTE: Use copper wire only.
MOTOR
1/8" MAX BETWEEN
MOTOR AND FAN HUB
CHECKING COOLING AND HEATING
CONTROL OPERATION
Start and check the unit for proper control operation as follows:
1. Place room thermostat SYSTEM switch in OFF position.
C99056
Observe that blower motor starts when FAN switch is placed
in ON position and shuts down within 60 sec. when FAN
switch is placed in AUTO position.
2. Place SYSTEM switch in COOL position and FAN switch in
AUTO position. Set control below room temperature. Observe
that cooling cycle shuts down when control setting is satisfied.
3. Place system switch in HEAT position. Set control above
room temperature. Observe that compressor, outdoor fan, and
indoor blower motor starts. Observe that heating cycle shuts
down when control setting is satisfied.
4. When using an automatic changeover room thermostat, place
both SYSTEM and FAN switches in AUTO positions. Ob-
serve that unit operates in Cooling mode when temperature
control is set to "call for Cooling" (below room temperature),
and unit operates in Heating mode when temperature control
is set to "call for Heating" (above room temperature).

CHECKING AND ADJUSTING REFRIGERANT CHARGE

The refrigerant system is fully charged with R-22 refrigerant and
A05141
is tested and factory sealed. Allow system to operate a minimum
of 15 minutes before checking or adjusting charge.
NOTE: Adjustment of the refrigerant charge is not required
unless the unit is suspected of not having the proper R-22 charge.
The charging label and the tables shown refer to system tempera-
tures and pressures in cooling mode only. A refrigerant charging
label is attached to the outside of the service access door. If charge
level is suspect in Heating mode, reclaim all refrigerant and charge
to nameplate amount. (This information may be obtained from the
physical data table also.)
IMPORTANT: When evaluating the refrigerant charge, an indi-
cated adjustment to the specified factory charge must always be
very minimal. If a substantial adjustment is indicated, an abnormal
condition exists somewhere in the cooling system, such as insuf-
ficient airflow across either coil or both coils.

REFRIGERANT CHARGE

The amount of refrigerant charge is listed on the unit nameplate
and/or the physical data table. Refer to the Refrigeration Service
Techniques Manual, Refrigerants Section.

NO CHARGE

Check for leak. Use standard evacuating techniques. After evacu-
ating system to 500 microns, weigh in the specified amount of
C99070
refrigerant (refer to system data plate).

LOW CHARGE COOLING

Use Cooling Charging Charts (See Table 8). Vary refrigerant until
the conditions of the chart are met. Note that charging charts are
different from type normally used. Charts are based on charging
the units to correct superheat for the various operating conditions.
12
MOTOR SHAFT
Fig. 16—Fan Blade Clearance
FAN GRILLE
1/2˝
C99009