SAIL SWITCH AND SAIL (FLAPPER)
Service Instructions
1. Shut off the gas supply to the heater.
2. Disconnect the heater from its electrical supply.
3. Open the case fan access panel on the control box
end of the heater.
4. Disconnect the motor leads.
5. Remove the screws securing the motor mounting
plate to the fan housing.
6. Pull the fan and motor assembly from the housing.
7. Loosen the square head set screw(s) on the fan
wheel with a wrench.
8. Pull the fan wheel from the motor shaft. Use a wheel
puller if necessary.
9. Remove the four (4) nuts securing the motor to the
mounting plate.
10. To replace the motor and fan, reverse the above
procedures.
NOTES: a. Fan wheel to motor mount plate spacing
must be adjusted to 3.2 mm clearance
before tightening the fan wheel to the
motor shaft.
b. Make sure that set screw(s) of the fan are
on the “flats” of motor shaf t when
tightening.
FIG. 8
MOTOR AND FAN WHEEL ASSEMBLY
13
MOTOR MOUNT PLATE
FAN WHEEL
CLEARANCE
MOTOR
BLOWER OUTLET
OF HEATER
AIR PROVING
SWITCH
ARM OF
FLAPPER
AIR PROVING
SWITCH ARM
FAN WHEEL
PIVOT POINT
OF FLAPPER
EDGE OF
FLAPPER
PIVOT POINT
OF FLAPPER
FLAPPER
31.7 MM TO 34.9 MM
1. Shut off the gas supply to the heater.
2. Disconnect the heater from its electrical supply.
3. Make sure there is not any dust, dirt, etc. that will
cause “binding” on the pivot points of the sail as it
rides within the blower housing. If debris is found,
use a soft brush or compressed air to clean the area
as necessary.
4. The “arm” of the sail should engage the arm of the
sail switch when the trailing edge of the sail body is
lifted and is approximately 31.7 mm to 34.9 mm off
the blower housing bottom. At this distance you will
hear a “click” which are the contacts closing within
the switch mechanism.
5. If the switch contacts do not close within this
distance, then manually push in the arm in the switch
to make sure the switch is not defective. If a “click” is
heard, the switch is good and the sail arm then needs
to be adjusted to engage the switch arm.
6. Using a needle nose pliers, gently bend up the arm of
the sail
(NOT THE SWITCH ARM)
in increments until
the sail arm engages the switch arm, closing the
contacts of the switch when the sail body trailing
edge is 31.7 mm to 34.9 mm from the housing
bottom.
FIG. 9
