Motor Overload Protection; Compressor Overcurrent; Astp Protection Trip; High Discharge Gas Temperature Protection - Carrier AquaSnap 30MPA Series Controls, Start-Up, Operation, Service, And Troubleshooting

If there is a command for a compressor to run and there is
no current, then one of the following safeties or conditions
have turned the compressor off:
Compressor Overcurrent — All compressors have internal
line breaks or a motor protection device located in the com-
pressor electrical box.
Compressor Short Circuit — There will not be current if the
compressor circuit breaker that provides short circuit protection
has tripped.
Compressor Motor Over Temperature — The internal line-
break or over temperature switch has opened.
High-Pressure Switch Trip — The high-pressure switch has
opened. See Table 44 for the factory settings for the fixed high-
pressure switch.
ASTP Protection Trip (30MP015-045 Only) — All non-digi-
tal Copeland compressors are equipped with an advanced
scroll temperature protection (ASTP). A label located above
the terminal box identifies models that contain this technology.
See Fig. 33.
Advanced scroll temperature protection is a form of internal
discharge temperature protection that unloads the scroll com-
pressor when the internal temperature reaches approximately
300 F (149 C). At this temperature, an internal bi-metal disk
valve opens and causes the scroll elements to separate, which
stops compression. Suction and discharge pressures balance
while the motor continues to run. The longer the compressor
runs unloaded, the longer it must cool before the bi-metal disk
resets. See Fig. 34 for approximate reset times.
Fig. 33 — Advanced Scroll Temperature
Protection Label
120
110
100
90
80
70
60
50
40
30
20
10
0
0 10 20 30
Compressor Unloaded Run Time (Minutes)
*Times are approximate.
NOTE: Various factors, including high humidity, high ambient temperature,
and the presence of a sound blanket will increase cool-down times.
Fig. 34 — Recommended Minimum Cool Down
Time After Compressor is Stopped*
To manually reset ASTP, the compressor should be stopped
and allowed to cool. If the compressor is not stopped, the motor
will run until the motor protector trips, which occurs up to 90
minutes later. Advanced scroll temperature protection will reset
* Copeland is a registered trademark of Emerson Climate
Technologies.
40 50 60 70 80 90
automatically before the motor protector resets, which may
take up to 2 hours.
High Discharge Gas Temperature Protection — Units
equipped with optional digital compressors have an additional
thermistor located on the discharge line. If discharge tempera-
ture exceeds 265 F (129.4 C), the digital compressor will be
shut off.
Alarms will also occur if the current sensor board malfunc-
tions or is not properly connected to its assigned digital input. If
the compressor is commanded OFF and the current sensor
reads ON, an alert is generated. This will indicate that a com-
pressor contactor has failed closed. In this case, a special mode,
Compressor Stuck on Control, will be enabled and all other
compressors will be turned off. An alarm will then be enabled
to indicate that service is required. Outdoor fans will continue
to operate. The condenser output is turned on immediately.

Motor Overload Protection

COPELAND* COMPRESSORS
ELECTRICAL CODE TF — Models with a "TF" in the
electrical code (i.e., ZP182KCE-TFE) have an internal line
break motor overload located in the center of the Y of the mo-
tor windings. This overload disconnects all three legs of the
motor from power in case of an over-current or over-tempera-
ture condition. The overload reacts to a combination of motor
current and motor winding temperature. The internal overload
protects against single phasing. Time must be allowed for the
motor to cool down before the overload will reset. If current
monitoring to the compressor is available, the system controller
can take advantage of the compressor internal overload opera-
tion. The controller can lock out the compressor if current draw
is not coincident with contactor energizing, implying that the
compressor has shut off on its internal overload. This will pre-
vent unnecessary compressor cycling on a fault condition until
corrective action can be taken.
COPELAND COMPRESSORS MODELS WITH ELEC-
TRICAL CODE TW OR TE
The electronic motor protection module is a safety device
that must not be bypassed or compressor damage may
result.
Models with a "TW" or "TE" in the electrical code (i.e.,
ZP182KCE-TWD or ZP182KCE-TED) have a motor over-
load system that consists of an external electronic control mod-
ule connected to a chain of four thermistors embedded in the
motor windings. The module will trip and remain off for a min-
imum of 30 minutes if the motor temperature exceeds a preset
point to allow the scrolls to cool down after the motor tempera-
ture limit has been reached. It may take as long as two hours for
the motor to cool down before the overload will reset.
NOTE: Turning off power to the module will reset it
immediately.
Restoring the compressor sooner may cause a destructive
temperature build up in the scrolls.
For this reason, module power must never be switched with
the control circuit voltage.
Current sensing boards monitor to the compressor current.
The ComfortLink control system takes advantage of the com-
pressor overload operation by locking out the compressor if
current draw is not detected. This will prevent unnecessary
compressor cycling on a fault condition until corrective action
can be taken.
54
MODELS WITH
CAUTION
CAUTION