I Unit Components - Lennox 80UGH Unit Information

SURELIGHT
IGNITOR
BURNER BOX
TOP
UPPER
BURNER
MOUNTING
RAIL
LOWER
BURNER
MOUNTING
RAIL
FLAME
SENSOR
ORIFICE
MANIFOLD
I−UNIT COMPONENTS (Figures 1, 2, 3)
80UHG unit components are shown in figure 1. The gas
valve, combustion air inducer and burners can be ac-
cessed by removing the burner access panel. Electrical
components are mounted to the blower housing.
80UHG units are factory equipped with bottom return air pan-
els in place. The panels are designed to be field removed as
required for bottom air return. Knockout panels are provided
for side return air.
ELECTROSTATIC DISCHARGE (ESD)
Precautions and Procedures
CAUTION
Electrostatic discharge can affect electronic
components. Take precautions during furnace
installation and service to protect the furnace's
electronic controls. Precautions will help to
avoid control exposure to electrostatic dis-
charge by putting the furnace, the control and
the technician at the same electrostatic poten-
tial. Neutralize electrostatic charge by touching
hand and all tools on an unpainted unit surface,
such as the gas valve or blower deck, before per-
forming any service procedure.
80UHG BURNER ASSEMBLY (shown in upflow position)
−2 MODEL SHOWN
ROLLOUT
SWITCHES
VEST PANEL
BURNER
GAS VALVE
BURNER BOX
FIGURE 3
1− Control Transformer (T1)
A transformer located on the blower housing provides
power to the low voltage section of the unit. Transformers
on all models are rated 30VA with a 120V primary and a
24V secondary.
2−Door Interlock Switch (S51)
A door interlock switch rated 16A at 125VAC is wired in se-
ries with line voltage. When the blower door is removed the
unit will shut down.
Shock hazard.
Spark related components contain high voltage.
Disconnect power before servicing. Control is
not field repairable. If control is inoperable, sim-
ply replace entire control.
Can cause injury or death. Unsafe operation will
result if repair is attempted.
Page 6
HEAT EXCHANGER
PRIMARY LIMIT
Top
Left
Front
Bottom
DANGER
Back
Right