Troubleshooting - Emerson CoreSense Technical Information

Technical Information
7

Troubleshooting

Flash
Alarm conditions
code
Warning: Appears
differential oil pressure is less than
0.48 – 0.62 bar for 4 seconds.
1
Lockout: Appears
Insufficient oil
differential oil pressure is less than
pressure
0.48 – 0.62 bar for 2 minutes
continuous, or
determined to be unsafe.
Trip: Appears
Thermistor resistance is > 4.5 kΩ.
2
Lockout: Appears
Motor overheat
consecutive motor
alarms occur.
Warning: When
temperature sensor is defective or
3 disconnected.
Discharge temp
Trip/Lockout: When the discharge
protection
temperature is
seconds.
Possible failure reasons
Loose wiring connections between
when the
™
CoreSense
sensor.
Faulty oil sensor (missing O-ring
when the
or clogged sensor screen).
Faulty oil pump.
intermittent but
Clogged strainer screen or worn
bearings.
Motor rotor
seized.
when the PTC
Open circuit in harness.
when 10
Connector pin not engaging at
overheat trip
connector on control module
Faulty CoreSense
Open discharge probe (faulty).
The probe connection has not
been made
connector.
the discharge
The connector is not plugged into
™
the CoreSense
The Discharge temperature has
> 154°C for 2
exceeded the
154°C.
Blocked condenser.
Possible loss of refrigerant.
Troubleshooting measures
Verify the oil level present in the sight glass. If the oil is not present, resolve reservoir
oil supply problem or oil level control setting issues.
module and oil
Verify that the harness is fully engaged to the sensor.
Measure oil pump differential pressure. If less than 7 to 9 psi, inspect for clogged oil
screen, faulty oil pump, liquid floodback or worn bearings.
If good oil pressure exists, measure resistance across the oil sensor while the
compressor runs. If the sensor resistance is "open" inspect for clogged sensor screen
or missing O-ring.
If sensor resistance is "closed", temporarily jumper across the harness connector pins
(do not damage the pins!) while the compressor runs. If the oil warning does not go
away, verify harness connector engagement at the module circuit board.
In case of trip alarm, allow the motor to cool down for a minimum of 2 minutes (it may
is mechanically
take longer) and the compressor will start automatically.
In case of lockout alarm or multiple trips, check PTC resistance when the motor is cold
(off for at least an hour). If resistance is high, inspect for faulty sensor or loose
connection under terminal plate.
If resistance is low, inspect for loose terminal strip connections, harness connection
failure at circuit board, open harness circuit or high motor temp due to return gas
™
module.
temperature, motor voltage or load condition.
If there is a warning, verify proper probe connection to the harness and proper
to the harness
harness connection into the circuit board.
If there is a warning, unplug the discharge temp probe and verify if the resistance of
the probe is as specified vs its approximate ambient temperature.
circuit board.
If the probe resistance is correct inspect the harness connector receptacle for damage
and apply NyoGel 760G connector lubricant.
maximum limit
Trip or Lockout: resolve system issues (high superheat, high head pressure), inspect
for mechanical damage that can lead to high temps (valve plate gasket, suction or
discharge valve failure).
D7.21.2/1011/E
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