Page 5
NOTE - During abnormal conditions such as low supply
voltage or low outdoor temperatures and the low fi re pres-
sure switch does not close, the combustion air inducer will
switch to high fi re. After a 15 second pre-purge the high
fi re pressure switch will close and the unit will begin op-
eration on high fi re. After 10 to 20 seconds of high fi re
operation the unit will switch to low fi 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 ener-
gizes during the trial until fl 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 be-
tween trials of 35 seconds. After a total of fi ve trials for
ignition (including the initial trial), the control goes into
Watchguard-Flame Failure mode. After a 60-minute reset
period, the control 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 fi re on fi rst-stage heat. The combustion air in-
ducer will operate on low speed and indoor blower will
operate on low heat speed. The unit will switch to second
stage heat after a “recognition period”. DIP switch 2, la-
beled 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 (two DIP switch
setting) the burners will fi re on fi rst-stage heat. The com-
bustion 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 fi rst and second stage
heat, the unit will fi re an fi rst stage heat and switch to sec-
ond stage heat after 30 seconds of operation. See Se-
quence of Operation fl 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 Combustuion Air Inducer
Neutral
5 Ignitor Neutral
TABLE 2
SureLight
®
Control 12 Pin Terminal Designation
PIN# Function
1 Gas Valve High Fire
2 Second Stage Prove Switch
3 Rollout In
4 Ground
5 24V Hot
6 Primary Limit In
7 Gas Valve Low Stage
8 Gas Valve Common
9 24V Neutral
10 Ground
11 Rollout Switch Out
12 1st 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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