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OPERATION
The red indicator light next to the 24VAC terminal block illuminates solid when the power is on. When the unit is
operating properly, the two (2) CPU lights will blink intermittently to indicate proper CPU operation.
BASIC TROUBLESHOOTING
If the VAV / VVR does not operate properly, perform the necessary troubleshooting as described below.
SYMPTOM
ACTION
Failure to communicate:
Check that the power is on and that the red indicator light is on.
If it is on, measure voltage at the 24VAC power terminals of the VAV to
ensure that the unit is getting 24VAC ( -10% / +5%).
Check the continuity and connection of the communication wires.
Check that the device address is correctly set.
Faulty Communication:
Check that all communication cables are connected as required, with drain
wires connected to a solid earth ground.
Check that all communication cable wires are connected “+” terminal to”+”
terminal and “-” terminal to “-” terminal.
Check for continuity on all communication signal lines.
Isolate sensor wiring from large contactors, fluorescent light fixtures, and
other sources of high-intensity electromagnetic interference (EMI).
Digital outputs not responding:
Disconnect the device wiring and check for continuity at the between
common ( C ) and normally open ( NO ) terminals based on output
position.
Check to see that exterior voltage source is present if used
to switch pilot relays.
Analog or digital inputs are jumpy:
Isolate sensor wiring from large contactors, motors, fluorescent light
fixtures, and other sources of high-intensity electromagnetic
interference (EMI).
