High Pressure Safety Switch; Refrigerant High Pressure Alarm; Phase Monitor; Compressor Operation - Bard FUSION-TEC WR36BPA Service Instructions Manual

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 26).

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.
Manual 2100-695
Page 28 of 54
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).
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.
FIGURE 44
Adjusting Compressor Delays
The address-based delay only applies to the wall-mount
unit when in orphan 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 LC, this is taken care of
by LC logic.

Compressor Low Temperature Limit

The unit has the ability to protect the compressor
from refrigerant flood-back in low outdoor temperature
conditions (0°F default). This will be automatically
enabled, unless the economizer is disabled by the
model number. This function can also be enabled/
disabled, and limit temp changed by the user.
To adjust compressor low temp limit:
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 B3.