Specialty Concepts SCS/90 - Manual (Page 18)

MONITOR DISPLAY NOT READING CORRECTLY
DISPLAY BLANK, ALARMS DO NOT FUNCTION
Check the fuse on the backside of the front plate on the display circuit board. If it is
blown, replace with a new 1 amp type agc fuse. If it continues to blow, this indicates
that the SCS probably needs servicing.
Inspect the wire connections to and from the display circuit board on the back of the
unit and confirm all connections are sound.
ALARMS DO NOT FUNCTION PROPERLY
Check alarm calibration. See Voltage Alarms section.
INCORRECT READINGS FOR AUX CURRENT
Check to be sure that the external shunt is wired in the negative leg of the system
component.
Using a digital multimeter, measure the millivolt reading at the shunt and then at the
terminal block of the display circuit board to which it is connected. Compare this
value with the expected current reading and the displayed value.
RANDOM READINGS
Check the wire connections to the terminals on the display circuit board and make sure
they are sound.
Electronic "noise" from inverters or other loads can sometimes influences the readings.
Some types of loads (fluorescent lights, inverters) can generate electronic "noise"
that sometimes interferes with the monitor reading, particularly when sense wires
from remote shunts run close to wiring to the load. Check to see if strange behavior
can be traced to the operation of a certain appliance.
CURRENT READINGS LESS THAN EXPECTED
Check to see that array modules and batteries are in the correct series-parallel
configuration for proper system voltage and current.
Check for an alternative path to ground around the shunt. .
Check output from the solar panel(s), and that they are not partially shaded or dirty.
INCORRECT VOLTAGE READINGS
With an accurate digital volt meter, check voltage readings at the battery and at the
monitor, to see if they agree. Voltage drops occur between the SCS and the battery
occasionally during maximum charging. Drops often occur through old fuses, fuse
holders or circuit breaker boxes and at loose or corroded connections.