67
Table 52 — Pressure (psig) vs. Voltage Drop Values for Suction Pressure Transducers
MAJOR SYSTEM COMPONENTS
General —
The 48/50PG single-package rooftop units con-
tain the
Comfort
Link™ electronic control system that monitors
all operations of the rooftop. The control system is composed
of several main control components and available factory-
installed options or field-installed accessories as listed in sec-
tions below. See Fig. 14-19 for the control and power schemat-
ics. Figures 20 and 21 show the layout of the control box, unit,
and thermistor and transducer locations.
Main Base Board (MBB) —
See Fig. 22 and Table 53.
The MBB is the center of the
Comfort
Link control system. It
contains the major portion of the operating software and con-
trols the operation of the unit. The MBB continuously monitors
input/output channel information received from its inputs and
from the Economizer Control Board (ECB). The MBB re-
ceives inputs from thermistors and transducers. The MBB also
receives the Current Sensor inputs for compressors and other
discrete or digital inputs. The MBB reads space temperature
(SPT) from either a T-55, T-56 or T-58 device and space tem-
perature offset (SPTO) from a T-56 device. See Field-Installed
Accessories section on page 82. The MBB controls 9 relays.
NOTE: The Main Base Board (MBB) has a 3-position instance
jumper that is factory set to ‘1’.
Do not change this setting.
Economizer Control Board (ECB) —
The ECB con-
trols the economizer actuator. See Fig. 23 and Table 54. The
control signal from the ECB uses either the MFT
(Multi-Function Technology) communication protocol or a 4 to
20 mA output signal as defined by the configuration
Configuration
→
ECON
→
E.CTL
. The ECB has inputs for
Indoor Air Quality (IAQ), Outdoor Air Quality (OAQ), and
enthalpy. It also controls two power exhaust outputs.
By digitally communicating with the ECB, the economizer
actuator is able to provide the damper position and diagnostic
information to the
Comfort
Link controller. The damper
position is displayed at
Outputs
→
ECON
→
EC.AP
. Diagnostic
information is displayed via Alert T414. More information
about these alarms is contained in the Alarms and Alerts
section.
NOTE: The Economizer Control Board (ECB) has a
4-position DIP switch that is factory set to ON (towards the
center of the board).
Do not change this setting.
Integrated Gas Control (IGC) Board —
The IGC
is provided on gas heat units. See Table 55 and Fig. 24. The
IGC controls the direct spark ignition system and monitors the
rollout switch, limit switch, and induced-draft motor Hall
Effect switch. The IGC is equipped with an LED (light-
emitting diode) for diagnostics. See the Troubleshooting
section for more information.
Low Voltage Terminal Strip (TB2) —
This circuit
board provides a connection point between the major control
boards and a majority of the field-installed accessories. See
Fig. 25 and Table 56. The interface connection for the Carrier
Comfort Network® (CCN) communication and interface con-
nection for the Local Equipment Network (LEN) communica-
tions are also located on the low voltage terminal strip.
PRESSURE
(psig)
VOLTAGE
DROP (V)
PRESSURE
(psig)
VOLTAGE
DROP (V)
PRESSURE
(psig)
VOLTAGE
DROP (V)
PRESSURE
(psig)
VOLTAGE
DROP (V)
0
0.465
68
1.135
136
1.804
204
2.474
2
0.485
70
1.154
138
1.824
206
2.493
4
0.505
72
1.174
140
1.844
208
2.513
6
0.524
74
1.194
142
1.863
210
2.533
8
0.544
76
1.214
144
1.883
212
2.553
10
0.564
78
1.233
146
1.903
214
2.572
12
0.583
80
1.253
148
1.922
216
2.592
14
0.603
82
1.273
150
1.942
218
2.612
16
0.623
84
1.292
152
1.962
220
2.631
18
0.642
86
1.312
154
1.982
222
2.651
20
0.662
88
1.332
156
2.001
224
2.671
22
0.682
90
1.351
158
2.021
226
2.690
24
0.702
92
1.371
160
2.041
228
2.710
26
0.721
94
1.391
162
2.060
230
2.730
28
0.741
96
1.410
164
2.080
232
2.749
30
0.761
98
1.430
166
2.100
234
2.769
32
0.780
100
1.450
168
2.119
236
2.789
34
0.800
102
1.470
170
2.139
238
2.809
36
0.820
104
1.489
172
2.159
240
2.828
38
0.839
106
1.509
174
2.178
242
2.848
40
0.859
108
1.529
176
2.198
244
2.868
42
0.879
110
1.548
178
2.218
246
2.887
44
0.898
112
1.568
180
2.237
248
2.907
46
0.918
114
1.588
182
2.257
250
2.927
48
0.938
116
1.607
184
2.277
252
2.946
50
0.958
118
1.627
186
2.297
254
2.966
52
0.977
120
1.647
188
2.316
256
2.986
54
0.997
122
1.666
190
2.336
258
3.005
56
1.017
124
1.686
192
2.356
260
3.025
58
1.036
126
1.706
194
2.375
262
3.045
60
1.056
128
1.726
196
2.395
264
3.065
62
1.076
130
1.745
198
2.415
266
3.084
64
1.095
132
1.765
200
2.434
268
3.104
66
1.115
134
1.785
202
2.454
270
3.124
Содержание 48PG24
Страница 68: ...68 Fig 14 Low Voltage Control Schematic 48PG20 28 Units without Humidi MiZer System a48 7627...
Страница 69: ...69 Fig 15 Low Voltage Control Schematic 48PG20 28 Units with Humidi MiZer System a48 8227...
Страница 70: ...70 Fig 16 Low Voltage Control Schematic 50PG20 28 Units without Humidi MiZer System a48 7778...
Страница 71: ...71 Fig 17 Low Voltage Control Schematic 50PG20 28 Units with Humidi MiZer System a50 8101...
Страница 72: ...72 Fig 18 Power Schematic Units without Humidi MiZer System a48 7628...
Страница 73: ...73 Fig 19 Power Schematic Units with Humidi MiZer System a48 8228...
Страница 74: ...74 Fig 20 Component Arrangement Units without Humidi MiZer System a48 8229...
Страница 75: ...75 Fig 21 Component Arrangement Units with Humidi MiZer System a48 8230...
Страница 105: ......
