FLAME SENSOR
Complete this procedure at least once during the heating season.
9. Install igniter retaining screw and tighten snugly. DO
NOT OVERTIGHTEN. Overtightening can cause cracks in
base of igniter, possibly leading to future igniter failure.
IMPORTANT
■
Do not handle the igniter by the igniter element. Doing
so may cause premature igniter failure. Handle the
igniter by its ceramic base, or by its leads.
■
Center the igniter shield over the igniter element,
making sure the shield does not touch the igniter
element, otherwise igniter damage will occur when the
igniter is energized..
■
Do not over tighten the igniter mounting screw.
Overtightening will crack the base of the igniter, leading
to premature failure.
IGNITER
SHIELD, IGNITER
SCREW
WASHER, LOCK
MALE CONNECTOR
FEMALE CONNECTOR
SCREW
BRACKET, IGNITER
BURNER, CASTING
SENSOR, FLAME
BURNER
FLAME
BURNER
CASTING
FLAME SENSOR
3/8 TO 1/2 IN.
1. To help maintain proper flame sense, the sensor
should be removed from its mounting bracket and its
metal rod cleaned using steel wool or emery cloth.
Rub briskly to remove build up of dust, dirt and
aluminum oxide. Be careful not to fracture the
ceramic base of the sensor. See Fig. 12 for sensor
location.
FIG. 12
2. Check the flame sensor’s ceramic base for any
cracks. If cracks are found, replace the sensor.
IMPORTANT
■
For proper flame sense operation, the flame sensor tip
must be properly positioned within the burner flame.
Normally 12.7 mm to 19 mm is sufficient. See Fig. 13.
FIG. 13
The high limit switch should be tested a minimum of once
per year when the heater is given a thorough cleaning.
1. Disconnect the heater from its electrical supply.
2. Remove the high limit switch from the heat chamber.
3. Holding the switch by one of its mounting legs or
electrical terminals, apply a small flame only to the
sensing surface on the back of the switch.
Be
careful not to melt the plastic housing of the switch
when conducting this test.
4. Within a minute, you should hear a “pop” coming
from the switch, which indicates the contacts of the
switch have opened.
5. Allow the switch cool down for about a minute before
firmly pressing the red reset button on the switch.
6. Check for electrical continuity across the switch
terminals to make sure the contacts have closed.
7. Reinstall the switch back into the heater. Reconnect
the heater to its electrical supply. Start the heater
and check for proper operation.
FIG. 14
TESTING THE MANUAL RESET HIGH LIMIT SWITCH
WARNING
Fire Hazard
■
Do not operate the appliance with the high limit switch
bypassed.
■
Operating the heater bypassed high limit switch may
lead to overheating, possibly resulting in a fire, with
subsequent damage to the heater, building damage, or
loss of livestock.
RESET BUTTON
SENSING
SURFACE
TERMINAL
FLAME
MOUNTING
LEG
15
12.7 MM to 19 MM
