Manual 2100-695C
Page
29 of 56
If ignoring the brownout is needed because of the
above conditions, three preset timers can be set by DIP
switches in order to delay signaling a power brownout
for a specific length of time after compressor contactor
is energized. This allows the compressor a time period
to start even if the voltage has dropped and allows the
voltage to recover. This delay only happens when the CC
terminal energizes. The delay can be set to 1 second (A
DIP switch), 5 seconds (B DIP switch) or 10 seconds (C
DIP switch); time is not cumulative—only the longest
setting will apply. If the voltage recovers during the
brownout delay period, the compressor will start.
If a brownout condition is detected by the 8201-169,
the troubleshooting light will flash blue. The light will
continue to flash until the cooling call is satisfied or
power is removed from the Y terminal. This condition
does not prevent operation, it only indicates that a
brownout condition was present at some point during
the cooling call. If a brownout condition is detected,
CC will be de-energized and will retry after the delay-
on-make timer is satisfied; this process will continue
until call is satisfied.
If user chooses the "do not ignore" position (all three
DIP switches "off") when the site has inadequate utility
or generator power, this could lead to the compressor
never starting. The control will see the brownout
immediately and not start.
A common scenario and one that has been seen in the
field is when a unit or units switches from utility power
to generator power. With slower transfer switches, the
time delay between the utility power and generator power
didn’t cause a problem. The units lost power, shut off
and came back on line normally. With the introduction of
almost instantaneous transfer switches, the millisecond
long power glitch can be enough that the compressor will
start to run backwards. In this scenario, the CCM will
catch this and restart the units normally.
High Pressure Safety Switch
All units have a high pressure switch as a safety device.
This device will open when pressure in the system
reaches 650 PSIG. The sensor is directly connected
to the dedicated compressor control module (see
High
Pressure Detection
on page 28).
Refrigerant High Pressure Alarm
When the wall-mount unit receives a signal from the
compressor control module (CCM) indicating a high
pressure event, the wall-mount unit will generate an
alarm. Upon receiving the alarm, the wall-mount unit
will remove the “Y” call from the CCM, resetting the
status of the CCM. The alarm will stay present on the
wall-mount unit until manually cleared with TEC-EYE
hand-held diagnostic tool.
In addition to the CCM, the discharge pressure
transducer is used to prevent a high pressure event.
When the discharge pressure is above the discharge
pressure alarm setpoint (set 30 PSI below high
pressure switch, which is 650 PSI), the system will
disable stage 2 of mechanical cooling.
Phase Monitor
Used only on three phase equipment, the phase monitor
is a compressor protection device that will prohibit
operation of the compressor if the device senses a
possible reverse-rotation situation due to incorrect
phasing. On a call for compressor (and only compressor),
the device will check incoming phase, check for severe
voltage imbalance and check for proper frequency.
Under nominal conditions, a green LED light will show
on the face of the monitor. If there is improper phasing,
voltage imbalance or frequency deviation, the device will
show a red LED light and prohibit compressor operation.
If a fault condition occurs, reverse two of the supply
leads to the unit.
Do not reverse any of the unit factory
wires as damage may occur.
Compressor Operation
The compressor will be enabled when the unit (in
orphan mode) or LC provide a cooling stage 1 call. The
compressor call from the controller has several delays
that may affect the start or stop time of the compressor
in regards to the cooling demand. The compressor has
a minimum on time of 120 seconds to prevent short
cycling the compressor. The compressor also has a
minimum off time of 120 seconds to prevent start
ups before the pressure in the refrigeration system
equalizes. When the second stage is engaged, it also
has a minimum run time of 120 seconds to allow the
system to stabilize before returning to single stage or
shutting down.
These delays can be changed by:
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
Compressor
Config B2
.
5. Press ENTER key to scroll to
Min On
or
Min Off
(see Figure 44).
FIGURE 44
Adjusting Compressor Delays
