98T-305
8.5 FRESH AIR MAKEUP VENT
The purpose of the vent is to provide ventilation for
commodities that require fresh air circulation and must
be closed when transporting frozen foods, or CA loads.
NOTE
The fresh air makeup vent must be closed for all
Controlled Atmosphere loads.
The fresh air makeup vent is also used to vent the
container prior to the door interlock system opening and
user entry, refer to section 10.7, page 113.
8.6 SAFETY AND PROTECTIVE DEVICES
System components are protected from damage by
safety and protective devices listed in Table 20. These
devices monitor the system operating conditions and
open a set of electrical contacts when an unsafe
condition occurs.
The entire CA system will shut down if one of the
following safety devices open:
S Control Contactor Fuse (F3)
S Control Circuit Fuse (F1, F2)
S Air Compressor Overload (IP-AM)
S Circuit Breakers (CB-1 or CB-2) of the
refrigeration unit
Table 20. Controlled Atmosphere Safety and Protective Devices
UNSAFE CONDITIONS
SAFETY DEVICES DEVICE SETTING
Excessive current draw on control
circuit
Fuse (F3) Opens at 10 amps
Excessive current draw by the
microprocessor
Fuse (F1 & F2) Opens at 5 amps
Excessive air compressor motor
temperature
Internal Protector (IP-AM) --
Automatic Reset
N/A
Abnormal pressures in the CA
system
Pressure Relief Valve Opens at 10.55 kg/cm@ (150 psig)
Abnormal temperature in the air
heater
High Air Temperature Switch
(HATS)
Opens at 82 ¦ 3 _C (180 ¦ 5 _F).
Closes at 70 ¦ 5 _C (158 ¦ 9 _F).
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