Carrier 38BYC Installation And Start-Up Instructions Manual page 7

OF2
OF1
O R T2 Y TI DFT
O
R
W2
Y
C
CES0110063,
CES0130024
Table 3—Defrost Control Speedup-
Timing Sequence
MINIMUM
PARAMETER
(MINUTES)
30–minute cycle 27
50–minute cycle 45
90–minute cycle 81
10–minute cycle 9
5 minutes 4.5
Fig. 10—Defrost Control
6. When you hear reversing valve change position, remove
screwdriver immediately; otherwise, control will terminate
normal 10-minute defrost cycle in approximately 2 sec.
NOTE: Length of defrost cycle is dependent upon length of time
it takes to remove screwdriver from test pins after reversing valve
has shifted.
7. Unit will remain in defrost for remainder of defrost-cycle time
or until defrost thermostat reopens at approximately 80°F coil
temperature of liquid line.
8. Turn off power to outdoor unit and reconnect fan motor lead
to OF2 on control board. (See Fig. 10.)
Step 14—Check Charge
Factory charge is shown on unit rating plate. To check charge in
cooling mode, refer to Cooling Only Procedure. To check charge
in heating mode, refer to Heating Check Chart Procedure.
COOLING-ONLY PROCEDURE
NOTE: If superheat- or subcooling-charging conditions are not
favorable, charge must be weighed in accordance with unit rating
plate ± 0.6 oz/ft of 3/8-in. liquid line above or below 15 ft
respectively.
C TEST 30 50 90
W1
A91444
MAXIMUM SPEEDUP
(MINUTES) (NOMINAL)
33 7 sec
55 12 sec
99 21 sec
11 2 sec
5.5 1 sec
EXAMPLE:
To calculate additional charge required for a 25–ft line set:
25 ft – 15 ft = 10 ft X 0.6 oz/ft = 6 oz of additional charge
Units installed with cooling mode TXV require charging with the
subcooling method.
1. Operate unit a minimum of 10 minutes before checking
charge.
2. Measure liquid service-valve pressure by attaching an accurate
gage to service port.
3. Measure liquid-line temperature by attaching an accurate
thermistor type or electronic thermometer to liquid line near
outdoor coil.
4. Refer to unit rating plate for required subcooling temperature.
5. Refer to Table 4. Find the point where required subcooling
temperature intersects measured liquid service-valve pressure.
6. To obtain required subcooling temperature at a specific
liquid-line pressure, add refrigerant if liquid-line temperature
is higher than indicated or reclaim refrigerant if temperature is
lower. Allow a tolerance of ± 3°F.
Table 4—Required Liquid-Line Temperature (°F)
LIQUID
PRESSURE AT
SERVICE VALVE
(PSIG)
134
141
148
156
163
171
179
187
196
205
214
223
233
243
253
264
274
285
297
309
321
331
346
359
HEATING CHECK CHART PROCEDURE
To check system operation during heating cycle, refer to the
Heating Check Chart on outdoor unit. This chart indicates whether
a correct relationship exists between system operating pressure and
air temperature entering indoor and outdoor units. If pressure and
temperature do not match on chart, system refrigerant charge may
not be correct. Do not use chart to adjust refrigerant charge.
7
REQUIRED SUBCOOLING
TEMPERATURE (°F)
5 10 15
71 66 61
74 69 64
77 72 67
80 75 70
83 78 73
86 81 76
89 84 79
92 87 82
95 90 85
98 93 88
101 96 91
104 99 94
107 102 97
110 105 100
113 108 103
116 111 106
119 114 109
122 117 112
125 120 115
128 123 118
131 126 121
134 129 124
137 132 127
140 135 130
20
56
59
62
65
68
71
74
77
80
83
86
89
92
95
98
101
104
107
110
113
116
119
122
125