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Troubleshooting Units Equipped With Energyx; System; Complete Erv Stoppage; Check Alarms - Carrier 48HC 04-28 Controls, Start-Up, Operation And Troubleshooting

Single package rooftop units with comfortlink controls version 3.x and puron (r-410a) refrigerant
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Table 24 — Pressure (psig) vs Voltage Drop Values for Suction Pressure Transducers
PRESSURE
VOLTAGE
(psig)
DROP (V)
0
0.465
2
0.485
4
0.505
6
0.524
8
0.544
10
0.564
12
0.583
14
0.603
16
0.623
18
0.642
20
0.662
22
0.682
24
0.702
26
0.721
28
0.741
30
0.761
32
0.780
34
0.800
36
0.820
38
0.839
40
0.859
42
0.879
44
0.898
46
0.918
48
0.938
50
0.958
52
0.977
54
0.997
56
1.017
58
1.036
60
1.056
62
1.076
64
1.095
66
1.115

Troubleshooting Units Equipped with EnergyX

System

COMPLETE ERV STOPPAGE

EnergyX units are a combination of the base rooftop unit and
an integrated ERV. The ERV requires communication from the
rooftop for operation. This section covers ERV troubleshooting
only. For rooftop troubleshooting refer to the base unit's Ser-
vice manual.
Complete ERV Stoppage
There are several conditions that can cause the ERV to shut-
down or appear to be shutdown:
•
General power failure.
•
Transformer's circuit breaker tripped.
•
ERV main power fuses blown.
•
Communication failures.
•
Active alarm on the base rooftop unit or the ERV prevent-
ing operation. Review alarms.
•
Programmed occupancy schedule. Rooftop Unoccupied
•
Rooftop indoor fan is off.
•
The airflow sensor tubing connected to the incorrect high/
low sensor ports in the outside air.

CHECK ALARMS

The ERV has 4 possible alarms based on options installed in
the ERV. These alarms are described in detail below. They all
PRESSURE
VOLTAGE
(psig)
DROP (V)
68
1.135
70
1.154
72
1.174
74
1.194
76
1.214
78
1.233
80
1.253
82
1.273
84
1.292
86
1.312
88
1.332
90
1.351
92
1.371
94
1.391
96
1.410
98
1.430
100
1.450
102
1.470
104
1.489
106
1.509
108
1.529
110
1.548
112
1.568
114
1.588
116
1.607
118
1.627
120
1.647
122
1.666
124
1.686
126
1.706
128
1.726
130
1.745
132
1.765
134
1.785
®
PRESSURE
VOLTAGE
(psig)
DROP (V)
136
1.804
138
1.824
140
1.844
142
1.863
144
1.883
146
1.903
148
1.922
150
1.942
152
1.962
154
1.982
156
2.001
158
2.021
160
2.041
162
2.060
164
2.080
166
2.100
168
2.119
170
2.139
172
2.159
174
2.178
176
2.198
178
2.218
180
2.237
182
2.257
184
2.277
186
2.297
188
2.316
190
2.336
192
2.356
194
2.375
196
2.395
198
2.415
200
2.434
202
2.454
show up as a T418 alarm in the ComfortLink controller. Press-
ing enter and escape together on the scrolling marquee or Nav-
igator display will expand the text and provide the specific
alarm condition. There are 4 status points viewed under Oper-
ating Modes on the scrolling marquee or Navigator display
→
(Operating Modes
OAU) for each alarm to help diagnose
which alarm caused the T418 in the ComfortLink controller.
These will all reset automatically when the situation has been
resolved.

T418 OAU Filter Dirty

The ERV's dirty filter alarm should only occur if the optional
Filter Maintenance Switch is installed on the ERV. The dirty
filter alarm activates due to an increase in differential pressure
across the filters. The EXCB's D16 LED will be turn on and
the OAU Dirty Filter Alarm point will be turned to on (Operat-
→
→
ing Modes
OAU
fect unit operation but serves as a warning to replace the filters.
It will automatically reset when the pressure differential falls
below setpoint. Verify proper operation by partially blocking
airflow through the ERV filters and confirming that the alarm
does trip.

T418 OAU MOTOR FAILURE

This alarm indicates a motor problem in the ERV, any one of
the motors can trip this alarm (outside intake, exhaust and/or
the wheel motor). The intake and exhaust motors have build in
motor diagnostics and the wheel motor status is a field accesso-
ry. Since these are feed into the same alarm, it is important to
66
PRESSURE
VOLTAGE
(psig)
DROP (V)
204
206
208
210
212
214
216
218
220
222
224
226
228
230
232
234
236
238
240
242
244
246
248
250
252
254
256
258
260
262
264
266
268
270
ALM.2 = On). The alarm does not af-
2.474
2.493
2.513
2.533
2.553
2.572
2.592
2.612
2.631
2.651
2.671
2.690
2.710
2.730
2.749
2.769
2.789
2.809
2.828
2.848
2.868
2.887
2.907
2.927
2.946
2.966
2.986
3.005
3.025
3.045
3.065
3.084
3.104
3.124
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