THERMOCOUPLE
SCREWS
UNION
PILOT LINE
18
This heater has two high limit switches. One is located near
the heat chamber. The other is located at the fan end of the
heater. The high limit switches should be tested a minimum
of once per year when when the heater is given a thorough
cleaning.
1. The high limit switches have different temperature
ratings. To eliminate confusion, remove and test only
one high limit switch at a time.
2. Holding the switch by one of its mounting legs or
electrical terminals, apply a small flame only to the
sensing portion on the back of the switch. Be ccareful
not tto m
melt tthe pplastic hhousing oof tthe sswitch w
when
conducting tthis ttest.
3. Shortly, you should hear the contacts of the switch
opening. Check for continuity across the switch
terminals to verify contacts have opened.
5. Allow the switch cool down 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. Start the
heater and check for proper operation.
FIG. 15
TESTING THE MANUAL RESET HIGH LIMIT SWITCH
WARNING
Fire H
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
1. Remove the hose from the sediment trap, and the
sediment trap from the gas control inlet.
2. Remove the screws securing the valve to the control
box.
3. Remove the pilot line and thermocouple from the gas
control, and loosen the union at the control valve
outlet.
FIG. 16
GAS CONTROL VALVE
