Lennox International Inc. o23v - Manual (Page 3)

Page 3
FIGURE 1
O23 GENERAL PARTS ORIENTATION
LIMIT SWITCH
CONTROL BOX
WITH FAN
CONTROL
BECKETT
AFII BURNER
INDOOR BLOWER
VARIABLE SPEED
BLOWER MOTOR
COMBUSTION AIR INTAKE
OBSERVATION PORT
CLEAN-OUT PORT
VENT OPENING
HEAT EXCHANGER
CLEAN-OUT PORT
I−UNIT COMPONENTS
General parts orientation for the O23V is shown in fig-
ure 1. The O23V control box, burner, limit switch and
clean-out ports may be accessed by removing the front
access panel. The blower can be accessed by removing
the blower access panel.
ELECTROSTATIC DISCHARGE (ESD)
Precautions and Procedures
CAUTION
Electrostatic discharge can affect electronic
components. Take precautions during unit instal-
lation and service to protect the unit’s electronic
controls. Precautions will help to avoid control
exposure to electrostatic discharge by putting
the unit, the control and the technician at the
same electrostatic potential. Neutralize electro-
static charge by touching hand and all tools on an
unpainted unit surface before performing any
service procedure.
A−Blower Control Board (A54) Figure 2
WARNING
Electric shock hazard. Can cause
injury or death. Before attempting to
perform any service or maintenance,
turn the electrical power to unit OFF at
disconnect switch(es). Unit may have
multiple power supplies.
O23V units are equipped with a variable speed motor
which is controlled by the A54 blower control board. Blower
control board settings and operation are described in this
section.
O23V units equipped with a variable speed motor are ca-
pable of maintaining a specified CFM throughout the exter-
nal static range. A particular CFM can be obtained by posi-
tioning jumpers (COOL, HEAT, and ADJUST) on the
blower control board. The HEAT and COOL jumpers are
labeled A, B, C and D; each letter corresponds with an air
volume (CFM) setting. The ADJUST jumper is labeled
Test, −, +, and Norm. The + and − pin settings are used to
add or subtract a percentage of the CFM selected in the
COOL mode only. The Test jumper is used to operate the
motor in the test mode.