Carrier 69NT40-561-300, Operation And Service Manual

Page: 92 / 174

T-365 4–58
NOTICE
P7-0 & P8 are included with “Auto2 & Auto3” only. P9-0 through P10 are included with “Auto2”
only.
P7 Tests - High Pressure Tests : Unit is run at full capacity without condenser fan running to make sure that the
HPS opens and closes properly.
P6-7 Digital Loader/Un-
loader Valve Test Passes if pressure and current changes are within predetermined values 3
seconds after DLV/DUV switch signal. If it does not pass then refer to
Sec-
tion 7.19
P6-10 Electronic Expan-
sion Valve Test The test records the suction pressure during the open valve position and
passes if the suction pressure increase is above 3 psi when the valve opens
for 10 seconds.
CODE TITLE DESCRIPTION
P7-0 High Pressure
Switch (HPS)
Opening Test Test is skipped if sensed ambient temperature is less than 7.2°C (45°F), re-
turn air temperature is less than -17.8°C (0°F), or the water pressure switch
is open. With the unit running, the condenser fan is turned off and a 900 sec-
ond (15 minute) timer is started. The right display shows Discharge Pressure
if the sensor is configured and valid, else Discharge Temperature. The unit
needs to disable Discharge Pressure limit and enable Current Limit checks.
The test fails immediately if:
-Ambient Temperature Sensor invalid
-Composite Return Temperature Sensor invalid
-HPS is open
The test fails if:
-HPS fails to open before 900 seconds total test time.
-Evaporator or Compressor IP Alarm.
-Calculated Dome Temperature exceeds 137.78°C (280°F).
-Discharge pressure exceeds 370 psig.
-Compressor Current exceeds limits
The test passes if HPS opens within the 15 minute time limit.
P7-1 High Pressure
Switch (HPS) Clos-
ing Test If return temperature greater than -2.4°C, set setpoint to -5.0°C, else set set-
point to -30°C. Restart unit according to normal startup logic. Run unit nor-
mally for 120 seconds.
The test passes if the high pressure switch closes within 75 seconds after
end of Test 7-0, else the test fails.
Test P7-0 must pass for this test to execute.
CODE TITLE DESCRIPTION