For H
Heaters W
With FFlapper:
1. Shut off gas supply and disconnect heater from
electrical source.
2. Disconnect air-proving switch leads.
3. Some models may have the air-proving switch
mounting nuts located on the inside of the fan
housing. Remove the motor and fan assembly from
the housing. Remove the nuts and pull the switch and
screws from the housing.
4. The replacement switch will ship with appropriate
quantity of nuts and two screws. Mount the
replacement switch so each mounting screw head is
located inside the fan housing with threads exposed
to the switch side of the housing.
Make sure on reassembly that two nuts per screw are
used as spacers between the switch and housing side
panel. These nuts are tightened securely against the
housing side panel. Slide the switch onto the screws
and secure the switch in place using the two
remaining nuts.
NOTE
:
When replacing the switch, make sure the arm of the switch
is located above the flapper arm.
Air-Proving Switch
Servicing
Instructions
For H
Heaters w
with AAir-PProving S
Switch aand PPaddle:
1. Shut off gas supply to heater and disconnect heater
from its power source.
2. Open case access panel on fan motor end of heater.
3. Remove two (2) sheet metal screws holding the air-
proving switch with bracket to blower housing.
Remove the assembly by turning switch assembly 90°
so the paddle on the switch arm can be pulled through
oblong hole on side of fan housing.
4. Disconnect the leads from the air-proving switch.
5. The replacement switch will be mounted to its
bracket.
6. To install switch with bracket, reverse above
procedure.
IMPORTANT
Make sure you don’t bend the switch arm when installing the
replacement switch. Bending the switch arm may create
ignition problems later.
August 1999
Screw H
Heads
Flapper
Two S
Spacer N
Nuts
per S
Screw
Flapper
Arm
8.5-1
1