Lennox G50UHi Series, Информация об устройстве

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Page 9
INTEGRATED IGNITION CONTROL 97L48
FIGURE 6
J58
J156
TABLE 1
IGNITION CONTROL 97L48 TERMINAL DESIGNATIONS
ACB COOL blower − cooling speed (line voltage)
ACB HEAT blower − heating speed (line voltage)
PARK
alternate blower speeds
ACB LOW
continuous low speed
ACC accessory terminal (line voltage)
TX
line voltage to transformer
HOT
120vac hot
HTG ACC heat only accessory (line voltage)
NEUTRAL
120vac neutral
24VAC HOT
24vac return from transformer
24VAC RTN 24vac from transformer
FLAME SENSE
flame sense terminal
TABLE 2
IGNITION CONTROL 97L48 J156 TERMINAL
DESIGNATIONS
PIN # FUNCTION
1 Ignitor
2 Not Used
3 Ignitor Neutral
4 Combustion Air Inducer Line Voltage
5 Not Used
6 Combustion Air Inducer Neutral
TABLE 3
IGNITION CONTROL 97L48 J58 TERMINAL
DESIGNATIONS
PIN # FUNCTION
1 Primary Limit In
2 Gas Valve Common
3 Roll Out Switch Out
4 Gas Valve 24V
5 Pressure Switch In
6 Pressure Switch and Primary Limit Out
7 Not Used
8 Roll Out Switch In
9 Ground
a−Electronic Ignition (See Figure 8)
On a call for heat the SureLight
®
control monitors the com-
bustion air inducer prove switch. The control will not begin
the heating cycle if the prove switch is closed (by−passed).
Once the proving switch is determined to be open, the com-
bustion air inducer is energized. When the differential in the
prove switch is great enough, the prove switch closes and a
15−second pre−purge begins. If the prove switch is not
proven within 2−1/2 minutes, the control goes into Watch-
guard−Pressure Switch mode for a 5−minute re−set period.
After the 15−second pre−purge period, the SureLight ignitor
warms up for 20 seconds during which the gas valve opens
at 19 seconds for a 4−second trial for ignition. The ignitor
stays energized during the 4−second ignition trial until
flame is sensed. If ignition is not proved during the 4−sec-
ond period, the control will try four more times with an inter
purge and warm−up time between trials of 35 seconds. Af-
ter a total of five trials for ignition (including the initial trial),
the control goes into Watchguard−Flame Failure mode. Af-
ter a 60−minute reset period, the control will begin the igni-
tion sequence again.
The SureLight control board has an added feature that pro-
longs the life of the ignitor. After a successful ignition, the
SureLight control utilizes less power to energize the ignitor
on successive calls for heat. The control continues to ramp
down the voltage to the ignitor until it finds the lowest
amount of power that will provide a successful ignition. This
amount of power is used for 255 cycles. On the 256th call
for heat, the control will again ramp down until the lowest
power is determined and the cycle begins again.