Page 10
NOTE - During abnormal conditions such as low supply
voltage or low outdoor temperatures and the low re pres-
sure switch does not close, the combustion air inducer will
switch to high re. After a 15 second pre-purge the high
re pressure switch will close and the unit will begin op-
eration on high re. After 10 to 20 seconds of high re
operation the unit will switch to low re.
After the 15-second pre-purge period, the SureLight ig-
nitor warms up for 20 seconds after which the gas valve
opens for a 4-second trial for ignition. The ignitor remains
energized during the trial until ame is sensed. If ignition
is not proved during the 4-second period, the control will
try four more times with an inter purge and warm-up time
between trials of 35 seconds. After a total of ve trials for
ignition (including the initial trial), the control goes into
Watchguard- Flame Failure mode. After a 60-minute reset
period, thecontrol will begin the ignition sequence again.
Two Stage Operation / Thermostat Selection DIP
Switch
The control can be utilized in two modes: SINGLE-STAGE
thermostat or TWO-STAGE thermostat. The thermostat
selection is made using a DIP switch and must be posi-
tioned for the particular application. DIP switch 1, labeled
T”STAT HEAT STAGE is factory-set in the OFF position
for use with a two-stage thermostat. Move the DIP switch
to ON for use with a single stage thermostat. While in the
single-stage thermostat mode, the burners will always re
on rst-stage heat. The combustion air inducer will oper-
ate on low speed and indoor blower will operate on low
heat speed. The unit will switch to second stage heat af-
ter a “recognition period”. DIP switch 2, labeled SECOND
STAGE DELAY, is factory set in the OFF position for a 7
minute recognition period. The switch can be moved to the
ON position for a 12 minute recognition period, after which
time the unit will switch to secondstage heat. While in the
two-stage thermostat mode, the burners will re on rst-
stage heat. The combustion air inducer will operate on low
speed and indoor blower will operate on low heat speed.
The unit will switch to second-stage heat on call from the
indoor thermostat. If there is a simultaneous call for rst
and second stage heat, the unit will re an rst stage heat
and switch to second stage heat after 30 seconds of oper-
ation. See Sequence of Operation ow charts in the back
of this manual for more detail.
TABLE 1
SureLight
®
Control 5 Pin Terminal Designation
Pin # Function
1 Ignitor
2 Combustion Air Inducer High
Speed
3 Combustion Air Inducer Low
Speed
4 Combustion Air Inducer Neutral
5 Ignitor Neutral
TABLE 2
SureLight
®
Control 12 Pin Terminal Designation
Pin # Function
1 Gas Valve Second Stage
2 Second Stage Prove Switch
3 Rollout Switch In
4 Ground
5 24V Hot
6 Primary Limit In
7 Gas Valve First Stage
8 Gas Valve Common
9 24V Neutral
10 Ground
11 Rollout Switch Out
12 First Stage Prove Switch
TABLE 3
SureLight
®
Control 6 Pin Terminal Designation
Pin # Function
1 Data Input From Motor
2 Common
3 Not Used
4 Data Output To Motor
5 5 Volt Bias Supply
6 Not Used
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