Page 20
SERVICE MUST BE PERFORMED BY A
QUALIFIED SERVICE AGENCY.
A.) Turn thermostat to “OFF” or lowest setting.
B.) Allow heater to cool.
C.) Turn off electric power to heater..
D.) Turn gas supply valve to “OFF”.
E.) Disconnect gas supply line from gas valve.
F.) From outside, remove six (6) screws
securing back of outer cabinet to air in
take and exhaust flanges. (See Figure 5).
G.) From inside, gently slide combustion tube
assembly forward and out of outer
cabinet. (See Figure 6).
H.) Disconnect air pressure switch tubing from draft
inducer. See Figure 18-A.
I.) Remove draft inducer. (See Figure 18-A).
J.) Disconnect ignition cable and pressure
switch tubing from top of burner box.
(See Figure 16).
K.) Remove screws securing collection box and
burner box flange to liner top, bottom, left side,
right side and back. (See Figure 19).
L.) Pull combustion tube assembly forward
and out of the liner. (See Figure 20).
M.) You can now inspect, clean or replace
tubular heat exchanger as needed. NOTE: If
combustion tube assembly is being replaced,
you must keep and use collection and burner
box from assembly being replaced.
N.) Carefully check integrity of all gaskets (replace
as needed), then reinstall combustion tube
assembly by reversing Steps L - A.
Follow lighting instructions to put heater
in operation.

TO REMOVE COMBUSTION TUBE ASSEMBLY FOR

INSPECTION, CLEANING AND REPLACEMENT

FIGURE 16
IGNITOR
IGNITOR
CABLE
PRESS URE
S W I T C H
TUBING
BURNER
BOX
FIGURE 19
FIGURE 20
For WOW253 / WOW254
FIGURE 18-A (For WOW253 / WOW254)
TRANSFORMER
CIRCUIT
BOARD
JUNCTION BOX
AIR INTAKE
CIRCULATING
BLOWER #1
LINER
PRESSURE
SWITCH
DRAFT INDUCER