5188236-BIM-A-0316
66
Johnson Controls Unitary Products
The pilot burner lights and the spark stops but the main burners
do not light.
1.
Check electrical connections between the ignition control
and the gas valve. If intact, check for 24 volts across
terminals “MV” and “GROUND” terminals. If no voltage
detected, replace ignition control. If voltage is present,
replace gas valve.
Main burners light but exhibit erratic flame characteristics.
1.
Adjust air shutters as described in “BURNER AIR
SHUTTER ADJUSTMENT” on page 57.
2.
Check the main burner orifices for obstruction and
alignment. Removal procedure is described in BURNER
INSTRUCTIONS on page 57. Clean or replace burner
orifices and burners as needed.
Unit Flash Codes
Various flash codes are utilized by the unit control board (UCB)
and the ignition control board (ICB) to aid in troubleshooting.
Flash codes are distinguished by the short on and off cycle
used (approximately 200ms on and 200ms off). To show normal
operation, the control boards flashes a 1 second on, 1 second
off “heartbeat” during normal operation. This is to verify that the
UCB and the ICB are functioning correctly. Do not confuse this
with an error flash code. To prevent confusion, a 1-flash, flash
code is not used.
Current alarms or active restrictions are flashed on the UCB
LED.
•
LAST ERROR
- When this button is pressed and released
one time within five seconds, it flashes the last five flash
codes on the board’s LED. The most recent alarm is
shown first and the oldest alarm is shown last.
When pressed and released twice within a five second
span, the fault history is cleared.
•
TEST RESET
- When this button is pressed and released
one time within five seconds, any anti-short cycle delays
(ASCD) is by-passed for one cycle.
When this button is pressed twice within five seconds, any
active lockouts are reset.
•
COMM SET UP
- If the board is to be networked with
other units, this button is used to set the network address.
The first time the button is pressed within five seconds, it
scans the bus, then assigns itself the first available
address {starts at 2}. It then flashes that address one time.
Pressing the button two times within five seconds causes
the control to flash its address.
Pressing the button three times within five seconds forces
the control to reset its address to 1, which is the factory
default.
Fan On And Off Delays
The fan ON and OFF delays can be field adjusted by pressing a
combination of buttons on the UCB.
•
Gas Heat Option #1
- Press the
LAST ERROR
and
TEST RESET
buttons simultaneously and then release.
The control flashes three times as it writes a 30 second
delay ON and a 90 second delay OFF to the program.
•
Gas Heat Option #2
- Press the
COMM SETUP
and
TEST RESET
buttons simultaneously and then release.
The control flashes four times as it writes a 30 second
delay ON and a 180 second delay OFF to the program.
•
Electric Heat
- Press and release the
COMM SETUP
and
LAST ERROR
buttons at the same time. The control
flashes twice on the LED as the control writes a 0 second
ON and a 30 second OFF fan delay to the control’s
program memory.
Figure 29: Unit Control Board
Comm Setup
Button
Last Error
Button
Test Reset
Button
Control Board
LED
