Lennox EL296DFE Series Manual page 7

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 flame is sensed. If igni-
tion 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 five 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.
NOTE - During abnormal conditions such as low supply
voltage or low outdoor temperatures and the low fire pres-
sure switch does not close, the combustion air inducer will
switch to high speed. After the low & high pressure switch
close, the unit will proceed with a 15 sec pre-purge, fol-
lowed by a 20 sec ignitor warm up, then igntion on high-
fire. After 10 to 20 seconds of high fire operation the unit
will switch to low fire.
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 fire on first-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 second-stage
heat. While in the two-stage thermostat mode, the burners
will fire on firststage 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 first
and second stage heat, the unit will fire on first stage heat
and switch to second stage heat after 30 seconds of oper-
ation. See Sequence of Operation flow charts in the back
of this manual for more detail.
SureLight Control 5 Pin Terminal Designation
®
Pin #
1
2
3
4
5
SureLight Control 12 Pin Terminal Designation
®
Pin #
1
2
3
4
5
6
7
8
9
10
11
12
Page 7
TABLE 1
Function
Ignitor
Combustion Air Inducer High Speed
Combustion Air Inducer Low Speed
Combustion Air Inducer Neutral
Ignitor Neutral
TABLE 2
Function
Gas Valve Second Stage
Pressure Switch Second Stage
Rolout Switch
Ground
24V Hot
Primary Limit In
Gas Valve First Stage
Gas Valve Common
24V Neutral
Ground
Primary Limit Out
Pressure Switch First Stage