Principles of Operation of
the Module UCM-CLD
RLC-SVU02F-E4
12
Balanced compressor starts
and hours
This feature is enabled/disabled in
balanced starts and hours (service
setting menu). When enabled, the
UCM will start the compressor with
the fewest starts and stop the
compressor with the greatest number
of operating hours, as determined by
the “compressor starts“ accumulator
and the “compressor hours“
accumulator. This will tend to balance
out hours and starts equally over both
compressors.
Phase imbalance protection
The Clear Language Display
monitors the current in each phase
and calculates the percentage of
imbalance as follows:
% imbalance = (Ix - I average)
I average
I average = (I1 + I2 + I3) / 3
Ix = phase with greatest difference
from I average (without regard
to sign).
If phase-unbalanced protection
(service setting menu) is enabled
and the average three-phase current
is greater than 80% RLA, and the
percent of imbalance is calculated
to exceed 15%, the UCM will shut
down the compressor and display a
CMR diagnostic.
Reverse rotation protection
The Clear Language Display
monitors incoming current during
start-up and will shut down the
compressor within one second if
phase reversal is detected.
C
CA
AU
UT
TIIO
ON
N
Phase relationship during
installation of unit power must be
carefully controlled to ensure
compressor protection against
reversed rotation.
Oil failure protection
The logic of the UCM uses a
comparison of the entering oil
temperature at the compressor, to
the saturated-condenser
temperature, to determine if there is
an oil line restriction.
The differential between the
entering-oil and the saturated-
condenser temperatures is referred
to as the “oil loss differential
setpoint“ in the service settings
menu.
If the entering oil temperature drops
2°C below the saturated-condenser
temperature for more than
30 minutes, the circuit will shut
down on a CMR diagnostic. The
diagnostic will be presented as:
OIL SYSTEM FAULT - CKT X
DIP switch settings
Compressor overload DIP switches.
IPC address
The IPC address sets the address for Inter-Processor Communications of the
Clear Language Display modules. The following are the IPC DIP switch
settings for the modules.
Module
IPC DIP
A20-1
A20-2
A52
A9
Switch
SW1
SW2
SW1
SW2
SW1
SW1
1
OFF
Based
OFF
Based
OFF
OFF
2
OFF
On
OFF
On
OFF
OFF
3
Motor
Motor
4
RLA
RLA
5