Manual 2100-670B
Page
21 of 33
At this point, the fan will be operating at full speed,
moving as much air as possible.
Second Stage Drop Out
The second stage of cooling will be disabled when the
liquid pressure reaches 620 PSI to reduce the required
condenser airflow.
High Pressure Cut Out
See chart in Figure 28.
Low Ambient Control
At low outdoor air temperatures, the fan motor will
cycle as a means of controlling the system's head
pressure to protect the system from freeze-up. The
process for this system is as follows: If the liquid
pressure falls to 375 PSI and a low temperature
condition is met, the condenser fan speed will begin
to slow down to allow the pressure in the system to
increase. The fan speed will continue to ramp down
until the liquid pressure reaches 340 PSI. At this
point, the fan will operate at minimum speed, until the
liquid pressure reaches 250 PSI.
Once the system reaches 250 PSI, the condenser fan
will turn off, allowing pressure to build up in the system.
The fan will remain off, while the compressor remains
running, allowing the head pressure to build up to 375
PSI. The fan will then turn back on at the maximum
speed, continuing the previously discussed cycle.
Additional Condenser Fan Alarms
Dirty Condenser Coil Alarm
The unit will continuously monitor system conditions
to determine if the condenser coil is dirty or blocked.
FIGURE 28
Condenser Fan Pressure Control
If the system monitors three consecutive cooling
cycles that indicate a dirty condenser coil, an alarm
will be generated. This alarm is a notification and will
automatically reset when conditions are no longer
present. The end user has the ability to adjust how
dirty the coil gets before an alarm is generated and how
many consecutive cycles before the alarm is triggered.
To change these settings:
1. Press MENU key to go to the Main Menu screen.
2. Press UP or DOWN keys and ENTER key to enter
TECHNICIAN password 1313.
3. Press UP or DOWN keys to scroll to
Adv System
Config
; press ENTER key.
4. Press UP or DOWN keys to scroll to
Dirty Cond
Alarm (B4)
; press ENTER key.
5. Press ENTER key to scroll to
Alarm Threshold
(see
Figure 29 on page 22).
6. Press UP or DOWN keys to adjust the % restriction
to desired level.
7. Press ENTER key to save value and move the
cursor to
Trips before alarm
.
8. Press UP or DOWN keys to change the
Trips before
alarm
to the desired value.
9. Press ENTER key to save.
10. Press ESCAPE key several times to return to Main
Menu screen.
Alarm index numbers: 161, 162, 163, 164
