I−Unit Components - Lennox EL195DF SERIES User Manual

I−UNIT COMPONENTS
ELECTROSTATIC DISCHARGE (ESD)
Precautions and Procedures
CAUTION
Electrostatic discharge can affect elec-
tronic components. Take precautions to
neutralize
touching your hand and tools to metal
prior to handling the control.
EL195DF unit components are shown in figure 1. The com-
bustion air inducer, gas valve and burners can be accessed
by removing the burner access panel. The blower and con-
trol box can be accessed by removing the blower access
door.
A−Control Box Components (Figure 2)
Unit transformer (T1) and integrated ignition control (A92)
are located in the control box. In addition, a door interlock
switch (S51) is located in the control box.
EL195DF Control Box
TRANSFORMER
(T1)
INTEGRATED IGNITION
FIGURE 2
1. Transformer (T1)
A transformer located in the control box provides power to
the low voltage section of the unit. The transformers on all
models are rated at 40VA with a 120V primary and 24V
secondary.
2. Door Interlock Switch (S51)
A door interlock switch rated 14A at 120VAC is located on
the control box. The switch is wired in series with line volt-
age. When the blower door is removed the unit will shut
down.
electrostatic charge
DOOR INTERLOCK
SWITCH (S51)
CONTROL
(A92)
3. Integrated Ignition Control (A92)
Shock hazard.
Disconnect power before servicing. Control is not
field repairable. If control is inoperable, simply re-
place entire control.
Can cause injury or death. Unsafe operation will
result if repair is attempted.
by
The ignition control system consists of an integrated con-
trol (figure 4) ignitor (figure 5) and flame sensor (figure 5).
The integrated control and ignitor work in combination to
ensure furnace ignition and ignitor durability. The inte-
grated control, controls all major furnace operations. The
integrated control also features a RED LED light for trou-
bleshooting and two accessory terminals rated at (1) one
amp. Tables 1 and 2 show jack plug terminal designations.
See table 3 for troubleshooting diagnostic codes. The ni-
tride ignitor is made from a non−porous, high strength pro-
prietary ceramic material that provides long life and
trouble free maintenance. The integrated control continu-
ously monitors line voltage and maintains the ignitor pow-
er at a consistent level to provide proper lighting and maxi-
mum ignitor life.
4−Pin Terminal Designation
PIN #
1 Combustion Air Inducer Line
2 Ignitor Line
3 Combustion Air Inducer Neutral
4 Ignitor Neutral
12−Pin Terminal Designations
PIN #
1 High Limit Output
2 Not Used
3 24V Line
4 Not Used
5 Rollout Switch Out
6 24V Neutral
7 High Limit Input
8 Ground
9 Gas Valve Common
10 Pressure Switch In
11 Rollout Switch In
12 Gas Valve Out
Page 6
WARNING
TABLE 1
FUNCTION
TABLE 2
FUNCTION