59
Protective Devices
Compressor Protection
Overcurrent
Each compressor has internal line break motor protection.
Overtemperature
Each compressor has an internal protector to protect it against
excessively high discharge gas temperatures.
High--Pressure Switch
If the high-pressure switch trips, the compressor will shut down
and the Circuit A High Pressure Alert will activate. Refer to the
alarm section for the High pressure alert.
Evaporator Fan Motor Protection
In the belt drive application, the VFD serves as the motor thermal
and over-current protection. Refer to Major Component’s section
for more detail on the VFD.
EQUIPMENT DAMAGE HAZARD
Failure to follow this caution may result in damage to the unit.
DO not bypass the VFD while running the motor. Do not
change VFD parameter associated with motor characteristics,
these are factory programmed for motor protection. Damage to
the motor or the VFD can occur.
CAUTION
!
Condenser--Fan Motor Protection
The ECM motor is protected from locked rotor and over-current
protection through the electronic control module attached to the
motor.
Saturated Suction Pressure (SSP)
If the SSP for a par t icular circuit is reading bel ow the al arm se t point
for an extended period of time, that ci rcuit wi ll be shut down. Af t er 15
minutes, the alarm will automatically reset. If this alarm occurs 3 times
consecutively, the circuit will remain locked out until an alarm reset is
initiated via CCN or manually via the SystemVut controller display
(see Alarms and Alerts section for more details).
Condensate Overflow Switch (COFS)
A separate factory installed device can detect a full drain pan. This
device consists of a pan sensor to detect the water level and a relay
control switch to read the sensor. The control switch is located in
the unit control box and feeds into the SystemVu control to trip a
condensate overflow fault. The relay switch is a normally open
device that closes when power is applied. If the sensor detects high
water levels for 10 seconds straight, it will open the contact
removing the input provided to the SystemVu control. The switch
will also turn its red LED on. If the water level is low enough for 5
minutes the relay will close again applying the input back to the
SystemVu controller. A blinking red LED on the switch indicates
that the sensor has been disconnected.
Space Mounted Sensors
Space Temperature Sensor (T--55)
The T-55 space temperature sensor (part no. 33ZCT55SPT) is a
field-installed accessory. The sensor is installed on a building
interior wall to measure room air temperature. The T-55 sensor also
includes an override button on the front cover to permit occupants
to override the Unoccupied Schedule (if programmed).
TB5-- 1 Sensor Input.............
TB5 -- 2 Sensor Common.............
Space Temperature Sensor (T--56)
The T-56 space temperature sensor (part no. 33ZCT56SPT) is a
field-installed accessory. This sensor includes a sliding scale on the
front cover that permits an occupant to adjust the space temperature
set point remotely. The T-56 sensor also includes an override
button on the front cover to allow occupants to override the
unoccupied schedule (if programmed).
TB5-- 1 Sensor Input...........
TB5 -- 2 Sensor Common...........
TB5-- 3 Setpoint Offset Input...........
Space Temperature Sensor Averaging
See Fig. 35 for space temperature averaging with T-55 sensors
only. If the use of one T-56 sensor is required, refer to Fig. 36.
To Next Page
Loading...
Need help?
General
