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DIAGNOSTIC
LEDs
DIP
SWITCHES
Integrated Contol
EL280UH units are equipped with a two-stage integrated
control. This control manages ignition timing and fan off
delays based on selections made using the control DIP
switches. The control includes an internal watchguard
feature which automatically resets the integrated control
when it has been locked out. After one hour of continuous
thermostat demand for heat, the watchguard will break
and remake thermostat demand to the furnace and auto-
matically reset the control to relight the furnace.
DIP Switch Settings
Switch 1 -- Thermostat Selection -- This unit may be
used with either a single-stage or two-stage thermostat.
The thermostat selection is made using a DIP switch
which must be properly positioned for the particular appli-
cation. The DIP switch is factory-positioned for use with a
twostage thermostat. If a single-stage thermostat is to be
used, the DIP switch must be repositioned.
a. Select "OFF" for two-stage heating operation controlled by a
two-stage heating thermostat (factory setting);
b. Select "ON" for two-stage heating operation controlled by
a single-stage heating thermostat. This setting provides a
timed delay before second-stage heat is initiated.
TWO-STAGE INTEGRATED CONTROL
1/4" QUICK CONNECT TERMINALS
SENSE = 120 VAC OUTPUT TO FLAME SENSOR
NEUTRALS= 120 VAC NEUTRAL
PARK = DEAD TERMINAL FOR UNUSED BLOWER LEAD
HEAT LOW = 120 VAC OUTPUT TO CIRC BLWR -- LOW HT SPEED
HEAT HIGH/ COOL LOW = 120 VAC OUTPUT TO CIRC BLWR --
COOL HIGH = 120 VAC OUTPUT TO CIRC BLWR -- HIGH COOL SPEED
THERMOSTAT CONNECTIONS (TB1)
ON-BOARD
LINKS
1= ERROR CODE RECALL
H= 24V HUMIDIFIER OUTPUT
L= LENNOX SYSTEM OPERATION MONITOR
W915
D
P I
S
W
T I
C
H
E (
) S
1 -- 2 Stage T'stat
W951
2 -- 2nd Stage Delay
3 & 4 -- Heat Off Delay
5 -- Cool Off Delay
FIGURE 30
Switch 2 -- Second Stage Delay (Used with Single-
Stage Thermostat Only) -- This switch is used to de-
termine the second stage on delay when a single-stage
thermostat is being used. The switch is factory-set in the
OFF position, which provides a 10-minute delay before
secondstage heat is initiated. If the switch is toggled to
the ON position, it will provide a 15-minute delay before
secondstage heat is initiated. This switch is only activated
when the thermostat selector jumper is positioned for SIN-
GLEstage thermostat use.
Switches 3 and 4 -- Heating Blower-Off Delay -- The
heating blower-on delay of 30 seconds is not adjustable.
The heating blower-off delay (time that the blower oper-
ates after the heating demand has been satisfied) can be
adjusted by moving switches 3 and 4 on the integrated
control. The unit is shipped from the factory with a heat-
ing blower-off delay of 90 seconds. The heating blower
off delay affects comfort and is adjustable to satisfy indi-
vidual applications. Adjust the blower off delay to achieve
a supply air temperature between 90° and 110°F at the
exact moment that the blower is de-energized. Longer
off delay settings provide lower supply air temperatures;
shorter settings provide higher supply air temperatures.
Table 8 provides the blower off timings that will result from
different switch settings.
Page 28
HIGH HEAT AND LOW COOL SPEED
DIP SWITCH FUNCTIONS
F
U
N
C
I T
Selects t/stat type (single or two-stage)
Second stage ON delay (single-stage t'stat)
Heating fan OFF delay
Cooling fan OFF delay
O
N
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