3-23
T-296
Table 3-7 Temperature Controller Pre-Trip Test Codes (Sheet 3 of 4)
Note, this test is skipped if the unit does NOT have:
A compressor discharge sensor (CPDS).
A discharge pressure transducer (DPT).
Condenser pressure transducer (CPT).
I
n addition, this test is skipped if:
The sensed ambient temperature is less than 7
_
C (45
_
F).
The return air temperature is less than --17.8
_
C (0
_
F).
The water pressure switch (WP) is open, indicating that the unit is operating
with a water-cooled condenser.
P7-0
High Pressure
Switch Closed
(Continued)
Pass/Fail Criteria:
Under conditions of the above NOTE; the test immediately
fails if the following inputs are sensed to be invalid:
Compressor discharge sensor (CPDS).
Discharge pressure transducer (DPT).
Condenser pressure transducer (CPT).
OR,
if any one of the following inputs are sensed to be invalid:
Return temperature sensor (RTS).
Ambient sensor (AMBS).
In addition, the test will fail if:
The high pressure switch (HPS) fails to open within 15 minutes.
The discharge temperature exceeds 138
_
C (280
_
F).
The discharge temperature is less than or equal to ambient temperature
plus 5
_
C (9
_
F).
The condenser pressure transducer (CPT) or discharge pressure transduc-
er (DPT) pressure exceeds 27.42 kg/cm
2
(390 psig).
P7-1
High Pressure
Switch Open
Requirements:
Test P7-0 must pass for this test to execute. Setup: The con-
denser fan is started and a 60 second timer is started.
Pass/Fail Criteria:
Passes the test if the high pressure switch (HPS) closes
within the 60 second time limit, otherwise, it fails.
P8-0
Perishable Mode
Heat Test
Setup:
If the container temperature is below 15.6
°
C (60
_
F), the set point is
changed to 15.6
°
C, and a 60 minute timer is started. The left display will read
“P8-0.” The control will then heat the container until 15.6
°
C is reached. If the
container temperature is above 15.6
°
C at the start of the test, then the test pro-
ceeds immediately to test P8-1 and the left display will change to “P8-1.”
Pass/Fail Criteria:
The test fails if the 180 minute timer expires before the con-
trol temperature reaches set point. The display will read “P8-0,” “FAIL.”
P8-1
Perishable Mode
Pull Down Test
Requirements:
Control temperature must be at least 15.6
°
C (60
_
F).
Setup:
The set point is changed to 0
°
C (32
_
F), and a 180 minute timer is
started. The left display will read “P8-1,” the right display will show the supply air
temperature. The unit will then start to pull down the temperature to the 0
°
C set
point.
Pass/Fail Criteria:
The test passes if the container temperature reaches set
point before the 180 minute timer expires.
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