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I-UNIT COMPONENTS
ELECTROSTATIC DISCHARGE (ESD)
Precautions and Procedures
CAUTION
Electrostatic discharge can aect electronic
components. Take precautions to neutralize
electrostatic charge by touching your hand and
tools to metal prior to handling the control.
EL195UHNE unit components are shown in gure 1. The
combustion air inducer, gas valve and burners can be ac-
cessed by removing the outer access panel. The blower
and control box can be accessed by removing the blower
access panel.
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.
DOOR INTERLOCK
SWITCH (S51)
INTEGRATED IGNITION
CONTROL
(A92)
TRANSFORMER
(T1)
CIRCUIT
BREAKER
(CB8)
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
voltage. When the blower door is removed the unit will
shut down.3.
Circuit Breaker (CB8)
A 24V circuit breaker is also located in the control box. The
switch provides overcurrent protection to the transform-
er (T1). The breaker is rated at 3A at 32V. If the current
exceeds this limit the breaker will trip and all unit opera-
tion will shutdown. The breaker can be manually reset by
pressing the button on the face.
4. Integrated Ignition Control (A92)
WARNING
Shock hazard.
Disconnect power before servicing. Control is not
eld repairable. If control is inoperable, simply
replace entire control. Can cause injury or death.
Unsafe operation will result if repair is attempted.
The hot surface ignition control system consisting of an
integrated control (gure 3 with control terminal designa-
tions in tables 1, 2 and 3), sensor and ignitor (gure 5).
The integrated control and ignitor work in combination to
ensure furnace ignition and ignitor durability. The integrat-
ed control, controls all major furnace operations. The inte-
grated control also features a RED LED for troubleshoot-
ing and two accessory terminals rated at (1) one amp. See
table 4 for troubleshooting diagnostic codes. The nitride
ignitor is made from a non-porous, high strength propri-
etary ceramic material that provides long life and trouble
free maintenance.
TABLE 1
4-Pin Terminal Designation
PIN # FUNCTION
1 Combustion Air Inducer Line
2 Ignitor Line
3 Combustion Air Inducer Neutral
4 Ignitor Neutral
TABLE 2
12-Pin Terminal Designations
PIN # FUNCTION
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
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