Field Troubleshooting The Coresense Communications Module; Scroll Functional Check - Emerson Copeland Scroll ZR KC Series Bulletin

If the compressor operates with the module
bypassed but will not operate when the module
is reconnected, then the control circuit relay in
the module is open. The thermistor protection
chain now needs to be tested to determine if
the module's control circuit relay is open due
to excessive internal temperatures or a faulty
component.
2. Check the thermistor protection chain located in
the compressor as follows:
De-energize control circuit and module power.
Remove the sensor leads from the module (S1
& S2). Measure the resistance of the thermistor
protection chain through these sensor leads with
an ohmmeter.
NOTICE ! Use an Ohmmeter with a maximum of
9 volts to check the sensor chain. The sensor
chain is sensitive and easily damaged; no
attempt should be made to check continuity
through it with anything other than an
ohmmeter. The application of any external
voltage to the sensor chain may cause
damage requiring the replacement of the
compressor.
The diagnosis of this resistance reading is as
follows:
• 200 to 2250 ohms – Normal operating range
• 2750 ohms or greater – Compressor
overheated – Allow time to cool
• zero resistance – Shorted sensor circuit –
Replace the compressor
• infinite resistance – Open sensor circuit –
Replace the compressor
If the resistance reading is abnormal, remove the
sensor connector plug from the compressor and
measure the resistance at the sensor fusite pins.
This will determine if the abnormal reading was
due to a faulty connector
On initial start-up, and after any module trip, the
resistance of the sensor chain must be below the
module reset point before the module circuit will
close. Reset values are 2250-3000 ohms.
3. If the sensor chain has a resistance that is
below 2250 ohms, and the compressor will run
with the control circuit bypassed, but will not
run when connected properly, the solid state
module is defective and should be replaced. The
© 2016 Emerson Climate Technologies, Inc.
replacement module must have the same supply
voltage rating as the original module.
NOTE: The Kriwan INT69 SU2 has been phased
out of production by Kriwan. Kriwan modules that
require replacement in the field should be replaced
with the CoreSense Communications module
listed in Table 4. Kriwan to CoreSense retrofit
instructions are listed at the end of this bulletin.
Field Troubleshooting CoreSense Communications
Module
A solid green LED indicates the module is powered
and operation is normal. A solid red LED indicates an
internal problem with the module. If a solid red LED is
encountered, power down the module (interrupt the T1-
T2 power) for 30 seconds to reboot the module. If a solid
red LED is persistent, change the CoreSense module.
CoreSense communicates Warning codes via a green
flashing LED. Warning codes do not result in a trip
or lockout condition. Alert codes are communicated
via a red flashing LED. Alert codes will result in a trip
condition and possibly a lockout condition. Table 6 lists
the flash code information for Warning and Alert codes
along with code reset and troubleshooting information.
For more information on CoreSense please refer to
AE8-1408.
Copeland Scroll Compressor Functional Check
A functional compressor test with the suction service
valve closed to check how low the compressor will pull
suction pressure is not a good indication of how well a
compressor is performing. Such a test may damage a
scroll compressor. The following diagnostic procedure
should be used to evaluate whether a Copeland Scroll
compressor is working properly.
1. Proper voltage to the unit should be verified.
2. The normal checks of motor winding continuity
and short to ground should be made to determine
if the inherent overload motor protector has
opened or if an internal motor short or ground fault
has developed. If the protector has opened, the
compressor must be allowed to cool sufficiently to
allow it to reset.
3. Proper indoor and outdoor blower/fan operation
should be verified.
4. With service gauges connected to suction
and discharge pressure fittings, turn on the
compressor. If suction pressure falls below normal
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AE4-1303 R15