18
This heater has two high limit switches. One is located on
the heat chamber face, while the other is located on the fan
housing at the opposite end of the heater. The high limit
switches 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. The high limit switches have different temperature
ratings. To eliminate confusion, remove and test only
one high limit switch at a time.
3. Holding the switch by one of its mounting legs or
terminals, apply a small flame only to the sensing
portion 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. Check for lack of electrical
continuity across the switch terminals to verify
contacts have opened.
5. Allow the switch to cool down for about a minute
before firmly pressing the 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. 13
TESTING THE MANUAL RESET HIGH LIMIT SWITCHES
WARNING
Fire Hazard
■
Do not operate the appliance with the high limit
switches bypassed.
■
Operating the heater with bypassed high limit
switches may lead to overheating, possibly resulting
in a fire, with subsequent damage to the heater,
building damage, or loss of livestock.
IGNITER
IGNITER CABLE
IGNITER / SENSOR
MOUNTING BRACKET
SCREWS
IGNITER TOP TO
BURNER TOP
12.7 MM
BURNER PORT
ELECTRODE GAP IS 3 MM AND
CENTERED OVER BURNER PORT
1. Shut off the gas supply to the heater.
2. Disconnect the heater from its electrical supply.
3. Open the burner end access panel.
4. The igniter and sensor assembly is located at the top
of the burner casting mounted on a bracket.
5. Disconnect the high voltage lead from the igniter by
pulling downward on the lead connector at the igniter.
6. Loosen the screws that secure the igniter bracket to
the burner and remove this assembly from the heater.
7. Remove the screws that secure the igniter to the
mounting bracket.
8. To assemble, reverse the procedure.
IMPORTANT
■
The igniter can accumulate dust or dirt over a period of
extended use thereby affecting its ability to spark. If the
spark appears to be weak, rub the igniter electrode and
ground rod with steel wool or emery cloth to remove any
build up.
■
Make sure the gap between the igniter electrode and
the ground rod is set at 3 mm. Check the igniter’s
ceramic base for cracks. If any cracks are found,
replace the igniter.
FIG. 12
RESET BUTTON
SENSING
SURFACE
TERMINAL
FLAME
MOUNTING
LEG