Ingersoll-Rand ReliaTel, Manual, Page: 75 / 176

RT-SVD03L-EN 75
• Variable speed compressor failed, fixed compressor
circuit available:
• The system will revert to the staged compressor
control.
• If compressor 2 disable input is active, only one
fixed speed compressor is to be available during
compressor stage-up efforts.
• Variable speed compressor available, fixed
compressor circuit failed:
• The system will utilize the variable speed algorithm
to stage the variable speed compressor as normal.
The fixed compressor will not be able to respond to
control requests.
• If compressor 2 disable input is active, up to 100%
of the variable speed compressor capacity is to be
available during compressor stage-up efforts.
Compressor VFD Alarm Output Lockout
During a HPC event, there is a possibility that the
compressor VFD drive will trip on an overcurrent
condition before the high pressure switch is active. To
prevent a cycling condition with the compressor VFD
drive, the following operation will be implemented.
If the HPC input on the VSM indicates a high pressure
condition on the VSPD compressor circuit, the system
will react identically the same as today's operation.
In the event that the system encounters the issue
described in the above problem statement, the
following logic will be used
• If the compressor VFD alarm is received in the first
3 minutes of ReliaTel
™ compressor request, the
compressor will shut down (as expected).
• The VSPD compressor will not be allowed to restart
until the compressor VFD alarm has cleared.
• If the compressor VFD alarm is received in the first
3 minutes of ReliaTel
™ compressor request 4
consecutive times, then the VSPD compressor will
be locked out on a manual diagnostic.
• If the VSPD compressor runs longer than 3 minutes,
the counter will be set to zero.
VSM Module Communication Failure
If the VSM module loses communication with the rest
of the ReliaTel
™ system, the unit will disable all VSPD
compressor operation and will generate a "VSM
Module Communication Failure" diagnostic. On units
with fixed speed compressors all compressors will be
disabled due to OD fan being controlled through the
VSM module.
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