Operation with Advanced Microprocessor with Graphics Control 27
3.13.1 LCD Display Contrast
The level of contrast due to the viewing angle of the LCD display can be adjusted using a small thumb
wheel at the upper left of the control board just under the cable going to the display. The control is
labeled RA1.
3.13.2 Nonvolatile Memory
All critical information is stored in nonvolatile memory. Setpoints, setup parameters, and component
run hours are kept inside the microcontroller in EEPROM. Information retained for data logging, 24
hour component run hour graphs, alarm history, and the water detection floor plan is kept in non-vol-
atile RAM.
3.13.3 DIP Switches
Equipment options are selected and enabled using DIP switches 1 to 7. These are located at the upper
left of the control board and are labeled SW1. Switch 1 is at the top. These switches are factory set
and should not require any user changes. The setting and function of the switches can be read from
the LCD display (see 3.8.4 - DIP Switches).
3.13.4 Control Outputs
Active control outputs are indicated with LEDs on the lower section of the control board. Each LED is
lit if the control output is active (on). Use these LEDs to assist in troubleshooting the system.
NOTE
The LCD backlighting will turn on when any key is pressed and will go off 5 minutes after the
last key is pressed.
Table 12 Control output LEDs
LED Control Output
R5 Heat Rejection
LLSV Liquid Line Solenoid Valve
HGBP Hot Gas By-Pass
C1 Compressor
RH1 Reheat Stage 1
RH2 Reheat Stage 2
HUM Humidifier
FAN Main Fan
HMV Humidifier Make-Up Valve
HGBP2 Low Fan Speed (DEHUM)
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