Rescue Mode (Emergency Mode); Functionality; Figure 15: Digital Operation - Emerson Copeland Eazycool OMTE-90D-TFD Application Manuallines

Figure 15: Digital operation

NOTE: When the digital valve on the compressor is discharged the compressor is loaded.
NOTE: At start-up the valve is energized for C20 start-up time, ie, time interval with the digital
valve energized before regulation starts. It ranges from 0 to 10 seconds (factory setting = 5
seconds).

2.13 Rescue mode (emergency mode)

In case of controller malfunction, the unit provides an emergency operation mode. The controller will
be completely bypassed and the system will continue to run based on low-pressure switch (B10)
cycling. The functionality of the high-pressure protection devices (B21 & B22) remain active for
safety.
NOTE: The low-pressure switch B10 in standard configuration is used as a safety device.
When activating the emergency running mode the cut-in and cut-out setpoints must be
adjusted according to the application requirements.

2.13.1 Functionality

The emergency mode can be activated by means of the "rescue mode" switch S3.
There are 2 circuit breakers (S1 [Compressor 1 ENABLE or STOP] and S2 [Compressor 2 ENABLE
or STOP]) to activate the compressors (the Digital compressor will perform as the fixed-speed
compressor [= 100% capacity]). In emergency mode, the system operator must decide if one or two
compressors should be activated to provide sufficient cooling capacity. Switching off one of the two
compressors with S1 or S2 will divide the cooling capacity by half. A time delay can be adjusted using
relay K42 to avoid compressor cycling in rescue mode (factory setting = 10 minutes). If two
compressors are activated in rescue mode (S11 & S12) both compressors will always run in parallel.
Also, the time delay is always applied to both compressors in parallel.
Compressors control is achieved by low-pressure switch B10. In standard operation mode, the B10
low-pressure cut-out switch is used as a safety device. In rescue operation mode, the settings must
be adapted to installation needs. The time delay for the compressor starts as soon the cut-in value
of B10 is reached. After time delay the active compressor (or both) will run with 100% cooling
capacity until low-pressure cut-out value B10 is reached then compressor(s) will stop.
The fans are automatically activated with the rescue mode switch. The EC fans are programmed to
run at maximum speed during emergency mode by help of input D1 on the EC fan.
There is no need for any adjustments on the fans during this operation mode.
NOTE: The SB1 button (test button) allows to bypass the low-pressure device B10. It
might be useful under certain system conditions to manually let compressors run.
Only qualified and trained technicians should manually activate the compressors.
Keep system pressures and temperatures within acceptable limits.
18 C6.1.9/0219/E