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clear the fault. This is accomplished by disconnecting
the electrical power to both the indoor and outdoor
units for 1 minute and then reconnecting power.
NOTE: If the system experiences a low refrigerant
pressure lock-out, the system should be evaluated
to determine the cause for the low pressure
condition and corrective action taken to eliminate
the cause. Possible causes include low refrigerant
charge, failed indoor blower motor, dirty return air
filter, or a dirty indoor coil in the cooling mode or
low refrigerant charge, a failed outdoor motor, or a
dirty outdoor coil in the heating mode.
8.7 Compressor Shut-Down
Sequence for High or Low
Refrigerant Pressure Fault
1. The compressor is commanded to operate at zero
(0) RPM for a minimum of 5 minutes.
2. The outdoor EXV will be directed to completely
close for a period of 5 minutes and will then open
up completely.
3. The outdoor fan motor will continue to operate
during the 5 minute compressor off delay.
4. The UODC and EcoNet
TM
Control Center will
display the applicable fault code.
5. If after 5 minutes cooling or heating demand
persists and the pressure has reached reset
conditions, normal system operation will resume
and the fault codes will be cleared from the UODC
and EcoNet
TM
Control Center displays.
6. If after 5 minutes cooling or heating demand
persists and the pressure has not reached reset
conditions, the outdoor fan motor will be shut down.
Once the pressure reaches reset conditions after
the 5 minute delay, normal system operation will
resume.
8.8 Overcurrent and Current
Imbalance
If the compressor current exceeds an acceptable level
for the compressor or inverter, the inverter will reduce
the compressor speed to allow the current to return
to an acceptable level. If there is a current imbalance
between the compressor 3-phase windings, the inverter
will shut the compressor down for 5 minutes and will
lock the compressor out if there are 3 faults within a
single call for operation.
8.9 Compressor Operation
Outside Envelope
If the inverter detects that the compressor motor torque
exceeds an acceptable level for the compressor, the
inverter will reduce the compressor speed to keep the
torque at an acceptable level.
8.10 Over and Under Voltage
If the supply voltage or internal DC voltage is not
within an acceptable operating range, the inverter will
shut the compressor off until the voltage returns to an
acceptable level.
8.11 Inverter Over Temperature
If the internal inverter temperature sensors detect
excessive temperatures within the inverter, the inverter
will reduce the speed of the compressor or shut the
compressor down until the temperatures drop to an
acceptable level. The compressor will be locked out if
there are 3 faults within a single call for operation.
8.12 Controls and
Communication Malfunction
If the controls senses a malfunction within the control
system or communications or if system model data is
not available, the controls will act to shut the system
down to prevent the system from operating at a
condition that could harm components.
8.13 Sensor Failure Default
Operation
If the controls sense an externally connected sensor
has failed, the system will enter a fail safe operating
mode and will continue to condition the space until the
sensor can be replaced. A fault code will be displayed
on the EcoNet
TM
Control Center and Universal Outdoor
Control identifying which sensor has failed. See
the table below for the default operation for a sensor
failure.
8.14 Exiting Active Protection
Lock-Out Mode
Exiting an Active Protection Lock-Out mode can be
accomplished by disconnecting electrical power to both
the indoor and outdoor units for 1 minute and then
restoring power. Keep in mind there was a reason for
the lock-out, so the fault code on the Universal Outdoor
Control (UODC) or EcoNet
TM
Control Center should
be read to assist with diagnosing the root cause of
the lock-out and corrective action should be taken to
prevent the system from repeating the lock-out.
System Protection
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