Bard W24G4 Installation Instructions Manual page 51

IGNITION SEQUENCE CONTROL
Ignition Source
Flame Sensing
Timings
- Prepurge
- Postpurge
- Inter-trial purge
- Pressure switch proving period
- Trials for ignition
- Trial for ignition
- Ignition sequence lockout
- Heat blower on - delay
- Heat blower off - delay
- Cool blower on - delay
- Cool blower off - delay
- Manual fan operations
- High limit control operation
- Flame rollout switch operation
NOTE 1: After the fourth limit trip on a given call for heat, there will be a 1-hour delay before the ignition sequence will restart.
After either high limit switch or flame rollout switch actuation, the inducer will operate for the 30-second postpurge and the
comfort air blower will operate for the selected off delay. If on Manual Fan operation, the comfort air blower will continue to
operate.
SAFETY UNITS
High limit/Rollout
Pressure switch
COMFORT FAN CONTROL
Heating Speed Fan
Normal operation
- ON delay
- OFF delay
Limit Operation
Flame Sense
Cooling Speed Fan
- ON delay
- OFF delay
Manual Fan
DIAGNOSTIC INDICATOR
A red LED is provided to indicate system faults as follows:
Steady ON - Control okay in standby, call for heat, cool or fan modes
Steady OFF - Internal control fault or no power. Also check 3A fuse on control.
1 flash - Lockout due to failed ignition or flame dropouts
2 flashes - Pressure switch open with inducer on
3 flashes - Pressure switch is closed with inducer off
4 flashes - Limit switch is open
5 flashes - Flame detected with gas valve closed
6 flashes - Compressor output delayed from short cycle/staging timer
The flash rate is 0.25 seconds on, 0.25 seconds off with 2.0 seconds pause between flash codes.
TABLE 18
Integrated Furnace and Blower Control Operation
24 VAC DSI
Remote
15 seconds
30 seconds (0 if cycle terminated before valve "on")
15 seconds
60 seconds
3 per ignition sequence
7 seconds total time to prove flame
60 minutes (after 3 trials for ignition), auto reset
- can be reset during the 60-minute lockout period by opening thermostat
circuit for 3 seconds or more
30 seconds (timing starts when ignitor cycles off)
90, 120, 150 seconds selectable; factory set at 120
7 seconds
60 seconds
Operates on selected heating speed and cycles off during ignition or burner
start-up sequence.
Automatic reset, ignition sequence restart. See Note 1.
Manual reset, igniton sequence initiated after switch is manually reset.
See Note 1.
SPST in 24 Volt
SPST, safe start check
30 seconds fixed. Timing starts when igniter de-energized.
3 selectable timings – 120 seconds standard can be changed to 90 or 150
seconds.
ON when limit OPEN
OFF after OFF delay when limit CLOSES
ON if flame is sensed and there is no call for heat.
7 seconds
60 seconds
ON continuously on HEATING speed. When call for cool, the fan switches
to COOLING speed. Then when thermostat satisfied, the fan switches back
to HEATING speed after COOLING OFF delay.
Manual 2100-721B
Page 51 of 54