Alarms And Alerts; Bitzer Protection Module; Field Troubleshootng Solid-State Motor Protection Module; Motor Protector Ptc Key Values - Carrier AquaSnap 30MPA Series Controls, Start-Up, Operation, Service, And Troubleshooting

Troubleshooting procedures described for the Kriwan mod-
ule section (page 55) are applicable to the CoreSense commu-
nication module.
BITZER * PROTECTION MODULE — The 30MP unit siz-
es 050-071 use Bitzer compressors, which are equipped with
24V Lodam motor protection modules. See Fig. 42. The mod-
ule opens the relay contact in the control circuit and locks out
immediately if the motor temperature exceeds the preset limit.
If a lockout occurs the compressor must cool to ambient tem-
perature and the unit alarm must be cleared manually before
the compressor will restart.
CAUTION
Do not apply external voltage to orange instrument leads,
even for test purposes. Damage to the Lodam protection
device may result.
Fig. 42 — External Motor Protection Module,
30MP050-071 Units
FIELD TROUBLESHOOTING SOLID-STATE MOTOR
PROTECTION MODULE — Follow the steps listed below
to troubleshoot the module in the field. See wiring diagram in
Fig. 3 and Fig. 4 or in terminal box cover.
1. De-energize control circuit and module power. Remove
the control circuit wires from the module (Terminals M1
and M2 or L and N). Connect a jumper across these "con-
trol circuit" wires. This will bypass the "control contact"
of the module.
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 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.
CAUTION
The motor protection system within the compressor is now
bypassed. Use this configuration to temporarily test mod-
ule only. Failure to do this may result in unit damage.
2. 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 or 11 and 14). Measure the resistance of the
thermistor protection chain through these sensor
leads with an ohmmeter.
IMPORTANT: Use an ohmmeter with a maximum of 9
volts to check the sensor chain. The sensor chain is sensi-
tive 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

Motor Protector PTC Key Values

Normal PTC resistance:
Trip resistance:
Reset resistance:
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. On
initial start-up, and after any module trip, the resistance of
the sensor chain must be below the module reset point be-
fore the module circuit will close. Reset values are 2250
to 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 replacement module must have the same supply volt-
age rating as the original module.
Alarms and Alerts —
or fault conditions, and may cause either one circuit or the
whole unit to shut down. They are assigned code numbers as
described in Table 54.
Automatic alarms will reset without operator intervention if
the condition corrects itself. The following method must be
used to reset manual alarms:
Before resetting any alarm, first determine the cause of the
alarm and correct it. Enter the Alarms mode indicated by the
LED on the side of the scrolling marquee display. Press
and until the sub-menu item RCRN "RESET
ENTER
ALL CURRENT ALARMS" is displayed. Press
The control will prompt the user for a password, by displaying
PASS and WORD. Press
word, 1111. Press
ENTER
has been changed, use the arrow keys to change each individu-
al character. Toggle the display to "YES" and press
The alarms will be reset.
* Bitzer is a registered trademark of Bitzer Kuhlmaschinenbrau
GmbH.
59
250 to 2250 Ohms
>4500 Ohm ± 20%
<2750 Ohm ± 20%
These are warnings of abnormal
ENTER
to display the default pass-
ENTER
for each character. If the password
ENTER
.
.