284806-YIM-B-0707
62
Unitary Products Group
OPTIONAL VAV CONTROL BOARD FLASH CODES
Flash codes are also utilized by the VAV add-on board
to aid in troubleshooting optional VAV applications.
Flash codes are displayed by a red LED located near
the center of the board using a short on/off cycle
(approximately 200-ms on and 200-ms off).
To verify that the board is functioning correctly, the
LED will display a repetitive 1 second on, 1 second off
"heartbeat". Do not confuse this "heartbeat" with the
error flash codes shown in the table below. To prevent
confusion, a 1-flash, flash code is not used.
TABLE 31: VAV CONTROL BOARD FLASH CODES
FLASH CODE
DESCRIPTION
On Steady
Control Failure
1 Flash
Not Applicable
2 Flashes
Loss of Communication with UCB
3 Flashes
Space Sensor Failure
4 Flashes
SAT Sensor Failure
5 Flashes
RAT Sensor Failure
6 Flashes
OAT Sensor Failure
7 Flashes
OH Sensor Failure
8 Flashes
RH Sensor Failure
9 Flashes
IAQ Sensor Failure
10 Flashes
OAQ Sensor Failure
11 Flashes
APS Switch Failure
12 Flashes
Limit 2 Switch Open
13 Flashes
Purge
14 Flashes
VFD Input Failure
15 Flashes
Dirty Filter Switch
OFF
No Power or Control Failure