Manual 2100-670
Page
22 of 32
Upon receiving the alarm, the wall unit will remove
the “Y” call from the CCM, resetting the status of the
CCM. The alarm will stay present on the wall unit until
manually cleared.
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 pounds below high
pressure switch, which is 650), 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 stand
alone mode) or LV 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 180 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
Unit Config
(B2)
; press ENTER key.
5. Press ENTER key to scroll to
Min On
,
Min Off
,
Min On Same
,
Unloader Del or Address Delay
(see
Figure 28).
6. Press UP or DOWN keys to change the value.
7. Press ENTER key to save value and move the
cursor to next parameter or top of screen.
8. Press ESCAPE key several times to return to Main
Menu screen.
The address-based delay only applies to the wall unit
when in stand alone mode. The controller will delay the
unit compressor based on the value entered on screen
B2 multiplied by the unit address. This is intended to
keep multiple units from starting their compressors
at the same time when there is a quick change in the
load. When connected to the LV, this is taken care of by
LV logic.
FIGURE 28
Adjusting Compressor Delays
Additional Compressor Alarms
Refrigerant Low Pressure Alarm
When the low pressure transducer indicates a pressure
value less than the low pressure alarm setpoint of
40 PSIG and there is an active call for cooling,
the controller will disable the compressor (after a
180-second delay).
NOTE:
The second call will be
delayed based on the delay off value mentioned in the
compressor section.
The controller will try to run the
refrigeration system two (2) times within 900 seconds
before the alarm will lock the compressor out. This
alarm needs to be manually cleared before compressor
operation will resume.
To adjust the low pressure alarm settings:
1. Press MENU key to go to the Main Menu screen.
2. Press UP or DOWN keys and ENTER key to enter
USER password 2000.
3. Press UP or DOWN keys to scroll to
System Config
;
press ENTER key.
4. Press UP or DOWN keys to scroll to
Alarm Setup
(A6)
; press ENTER key.
5. Press ENTER key to scroll to
Delay
to adjust how
long the compressor waits before turning the
compressor off (see Figure 29).
6. Press UP or DOWN keys to adjust the time delay.
7. Press ENTER key to scroll to
Two Count Del
.
