Air Proving Switch; Manual Reset High Limit Switch - L.B. White Guardian AW060 Owner's Manual And Instructions

Guardian Agricultural Animal Confinement Building Heaters
b. Make sure that set screw(s) of the fan are on the
flats of motor shaft when tightening.
FIG. 8
MOTOR MOUNT PLATE
MOTOR

Air Proving Switch

The air proving switch is located on the fan housing at
the motor end of the brood heater. It must work prop-
erly to allow an ignition cycle. If the air proving switch
contacts are closed before the igntion control starts the
fan motor, or do not close on a call for heat after the fan
motor starts, ignition will not occur . See Fig. 9a or 9b.
AW060/AW100/AW250 service (Fig. 9a):
-- Remove the two (2) sheet metal screws holding
the switch with bracket to blower housing.
-- Remove the assembly by turning the switch so the
paddle on the switch arm can be pulled through
the oblong hole on side of fan housing.
AW325 service (Fig. 9b):
-- Remove the two mounting nuts and slide the
switch from its mounting screws.
FIG. 9a
AIR PROVING SWITCH
FAN WHEEL
CLEARANCE
AD060/AD100; 6mm
AD250/325; 3 mm
Owner's Manual • Guardian
FIG. 9B
AIR PROVING SWITCH
Manual Reset High Limit
Switch
WARNING
Fire Hazard
■ Do not operate the brood heater with the high
limit switch bypassed.
■ Operating the brood heater a bypassed high
limit switch may lead to overheating, possibly
resulting in a fire, with subsequent damage to
the brood heater, building damage, or loss of
livestock.
This brood heater uses a high limit heat switch for the
purpose of over heat protection. The high limit switch
is located on the heat chamber, see Fig. 10, AW250
shown. It is connected between the ignition control and
the gas control valve.
The switch has normally closed contacts. If an overheat
condition occurs, the switch contacts will open, thereby
opening the circuit to the gas control valve. The high
limit switch should be tested a minimum of once per
year when the heater is given a thorough cleaning.
1. Remove the switch. Holding the switch by one of its
mounting legs, apply a small flame only to the sens-
ing portion on the back of the switch. See Fig. 11.
Do not melt the plastic housing of the switch when
conducting this test.
2. 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.
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