140
1. De-energize control circuit and module power. Remove
the control circuit wires from the module (terminals M1
and M2). Connect a jumper across these control circuit
wires. This will bypass the control contact of the module.
2. Re-energize the control circuit and module power. If the
compressor will not operate with the jumper installed,
then the problem is external to the solid-state protection
system. If the compressor operates with the module by-
passed but will not operate when the module is reconnect-
ed, then the control circuit relay in the module is open.
Remove the temporary jumper installed in Step 1.
3. 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.
Check the thermistor protection chain located in the com-
pressor as follows:
a. De-energize control circuit and module power.
b. Remove the sensor leads from the module (S1 and
S2).
c. Measure the resistance of the thermistor protection
chain through these sensor leads with an ohm
meter.
d. The diagnosis of this resistance reading is as fol-
lows:
• 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.
4. If the resistance reading is abnormal, remove the sensor
connector plug from the compressor and measure the re-
sistance at the sensor fusite pins. This will determine if
the abnormal reading was due to a faulty connector.
5. On initial start-up, and after any module trip, the resis-
tance of the sensor chain must be below the module reset
point before the module circuit will close. Reset values
are 2250 to 3000 ohms.
6. 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 replacement module must have the same supply volt-
age rating as the original module.
CoreSense Replacement of Kriwan Motor Protection
Module
— The Kriwan module has been replaced by the Core-
Sense communication module for motor protection. Minor
wiring changes are required as described below.
Removing the Kriwan motor protection module:
1. Disconnect and lock out the high voltage and control
voltage supply to the unit.
2. Using a straight blade screwdriver, carefully depress the
tabs holding the terminal cover to the terminal box to re-
move the terminal cover. Before proceeding, use a volt
meter to verify that the power has been disconnected
from the unit.
3. Using wire markers, label the M1, M2, T1, and T2 wires
that are connected to the Kriwan module. Using needle
nose pliers, remove the M1, M2, T1, T2, S1 and S2 wires
from the Kriwan motor protector module.
4. Gently bend the holding tabs holding the Kriwan module
in the terminal box and remove the Kriwan module from
the terminal box. See Fig. 161.
5. Take note of the S1-S2 plug orientation on the compres-
sor thermistor fusite. Remove the S1-S2 wire harness and
plug from the compressor.
Installing the CoreSense communications module:
1. A new S1-S2 thermistor wiring harness is shipped with
the CoreSense kit and must be used. The wiring harness
connector block should be fully inserted on the three pins
in the orientation shown in Fig. 162 for proper operation.
CAUTION
The motor protection system within the compressor is now
bypassed. Use this configuration to temporarily test mod-
ule only.
CAUTION
Use an ohmmeter with a maximum of 9 volts to check the
sensor chain. The sensor chain is sensitive and easily dam-
aged; 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.
WARNING
Electrical shock can cause personal injury and death. Shut
off all power to this equipment during installation and ser-
vice. There may be more than one disconnect switch. Tag
all disconnect locations to alert others not to restore power
until work is completed.
WARNING
Do not supply power to unit with compressor cover
removed. Failure to follow this warning can cause a fire,
resulting in personal injury or death.
HOLDING
TAB
HOLDING
TAB
a38-7310
Fig. 161 — Kriwan Motor Protection Module
Removal