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Operation with Advanced Microprocessor Controls
12
2.5.3 Run Diagnostics
By selecting Run Diagnostics, maintenance personnel can check system inputs, outputs, and complete
a test of the microcontroller circuit board, all from the front panel. Review of the system inputs and
the microcontroller test can be done without interrupting normal operation. To test the system out-
puts, the normal system control is temporarily suspended. DO NOT leave the unit in the diagnostics
mode any longer than is necessary for troubleshooting. The control system will return to normal oper-
ation in 5 minutes, automatically, if no key is pressed.
Show Inputs
With the unit on and the fan running, the input state for the following devices may be displayed:
• Air sail switch: normally off unless Loss of Air Alarm is active
• Custom alarm #1: normally off unless this alarm is active
• Custom alarm #2: normally off unless this alarm is active
• Custom alarm #3: normally off unless this alarm is active
• Custom alarm #4: normally off unless this alarm is active
• Humidifier problem: normally on unless this alarm is active
• Filter clog: normally off unless Change Filters Alarm is active
• Main fan overload: normally on unless Main Fan Overload Alarm is active
• Shutdown device: normally on unless unit is off through the Fire Stat or Remote Shutdown
Device
• Low press switch: normally on if compressor circuit is in operation
• Comp overload: normally on unless Compressor Overload Alarm is active
• High head comp: normally off unless High Head Pressure alarm Compressor is active
Test Outputs
When this feature is selected, the unit is effectively turned off. When stepping from one load to the
next, the previous load, if on, is turned off automatically. The loads can also be toggled ON/OFF by
selecting “ENTER.” Once turned on, the output will remain on for 5 minutes unless toggled off or the
Test Outputs function is exited by selecting “MENU/ESC.” (The compressor is limited to 15 seconds
on to prevent damage.) The outputs are as follows:
• Main fan: main fan contactor
• Comp: compressor contactor
• LLSV: liquid line solenoid valve
• HGBP/CUV: hot gas bypass or compressor unloader valve (on certain units)
• Part coil: part coil solenoid valve
• CWV/CGV: chilled water or GLYCOOL valve
• R5 Relay: Relay 5 (heat rejection)
• Reheat 1: Reheat 1 contactor (also energizes fan for safety) or SCR Reheats
• Reheat 2: Reheat 2 contactor (also energizes fan for safety)
• HWR: hot water solenoid valve
• Humidifier: humidifier contactor (also energizes humidifier makeup valve and fan for safety)
• HMV: humidifier makeup valve
• Comm alarm: common alarm relay
Test Control Board
By selecting this function, the microcontroller will perform a self test lasting approximately 10 sec-
onds. At the end of the test, the ROM checksum, ROM part number and version number will be dis-
played.
!
CAUTION
Do not test a compressor output for more than a few seconds. Compressor damage could
result!