Hussmann Proto-Aire EZ Manual Del Usuario página 29

Proto-Aire EZ I/O Manual
Input Devices
A. Ambient Temperature Sensor
The Ambient Temperature Sensor measures the ambient temperature and is mounted near the
inlet air side of the first condenser fan. The ambient temperature sensor is for monitoring only
and does not have a failure mode or impact system operation.
B. Discharge Pressure Transducer
The discharge pressure transducer measures the pressure within the discharge header. In the
event of a discharge pressure transducer failure condenser fans will remain on.
C. Suction Pressure Transducer
The suction pressure transducer measures the pressure within the suction header of the
associated suction group. In the event of a suction pressure transducer failure the compressors
will stage based on the suction group low pressure control and the associate compressor relay
output failure state (normally open or normally closed).
D. Circuit Temperature Probe
The circuit temperature probe is mounted near the evaporator and measures the circuit
temperature. In the event of a circuit temperature probe failure, the circuit will run in
refrigeration mode only until the probe failure is corrected.
E. Circuit Termination Probe/Klixon (if applied)
The circuit termination probe/Klixon is mounted near the evaporator and measures the
defrost termination temperature.
F. Circuit Door Switch
In the event of a door switch open failure, a door switch alarm will occur after the door
switch alarm delay time and will continue to alarm until the failure is corrected.
G. Phase Monitor
Each three-phase unit is equipped with a phase monitor that monitors the incoming
208VAC/3/60Hz power and will interrupt the power supply to the compressor and
condenser control circuits, preventing operation of all 208V loads. The phase monitor will
issue a single, general alarm to the rack controller in any of the following conditions:
•
Over/under voltage
• Phase loss
•
Phase reversal
•
Voltage imbalance
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