Carrier 50YX - Manual (Page 15)

data (ac
50YX
UNIT V-PH-HZ
OPERATING
VOLTAGE*
COMPRESSOR IFM
FLA
OFM
FLA
MCA
SIZE Max Min LRA RLA
018 50 0 10.7 1 8 1.4 16.6
024 62.5 12.9 35 1.4 21 0
030 76.0 15.0 35 22 24 5
036 208/230-1-60 254 187 90.5 20.0 35 22 30 7
042 107.0 22.0 35 22 33.2
048 129 26.4 47 2.2 39 9
060 169 32 2 67 2.8 49.8
LEGEND
CKT BKR — Circuit Breaker
FLA — Fuil Load Amps
HACR — Heating, Air Conditioning, and Refrigeration
IFM — indoor-Fan Motor
LRA — Locked Rotor Amps
MCA — Minimum Circuit Amps
OFM — Outdoor-Fan Motor
RLA — Rated Load Amps
MAX FUSEt
OR HACR CKT
BKR AMPS
25
30
35
50
50
60
60
‘Permissible iimits of the voltage range at which units wili operate
satisfactoriiy.
tMaximum duai element fuse.
NOTE. Use copper wire only.
Controls
Operating sequence
When power is supplied to unit, the transformer (TRAN) is
energized.
Cooling — With the thermostat subbase in the cooling po­
sition, and when the space temperature comes within 2° F
of the cooling set point, the thermostat makes circuit R-O.
This energizes the reversing valve solenoid (RVS) and places
the unit in standby condition for cooling.
As the stage temperature continues to rise, the second
stage of the thermostat makes, closing circuit R-Y through
the low-pressure switch (LPS). When compressor time de­
lay (5 ± 2 minutes) is completed, a circuit is made to con­
tactor (C), starting the compressor (COMP) and outdoor-fan
motor (OFM) Circuit R-G is made at the same time, ener­
gizing the indoor-fan relay (IFR) and starting the indoor-fan
motor (IFM) after one-second delay.
When the thermostat is satisfied, contacts open, deener­
gizing C. The COMP and OFM stop, and the IFM stops af­
ter a 45-second time delay.
Heating — On a call for heat, thermostat makes circuits
R-Y and R-G. Circuit R-Y is completed, allowing circuit
through LPS. When compressor time delay (5 ± 2 minutes)
is completed, a circuit is made to C, starting COMP and
OFM. Circuit R-G also is completed, energizing IFR and start­
ing IFM after one-second delay.
Should room temperature continue to fall, circuit R-W is
made through second-stage thermostat bulb. If optional elec­
tric heat package is used, a relay is energized, bringing on
first bank of supplemental electric heat. When thermostat is
satisfied, contacts open, deenergizing contactor and relay;
motors and heaters deenergize. The IFM is controlled by a
time-delay relay that keeps the fan on for 45 seconds.
Defrost — Defrost board (DB) is a time and temperature
control, which includes a field-selectable time period be­
tween checks for defrost (30, 50, and 90 minutes). Elec­
tronic timer and defrost cycle start only when contactor is
energized and defrost thermostat (DFT) is closed
Defrost mode is identical to cooling mode, except outdoor-
fan motor stops and a bank of optional electric heat turns
on to warm air supplying the conditioned space.
15