L.B. White Guardian 2.0 Owner's Manual And Instructions page 19

High Limit Switch
WARNING
Burn Hazard
■ Do not operate the heater with the high limit
switch bypassed.
■ Operating the heater a bypass high limit switch
may lead to overheating, possibly resulting in
a fire, with subsequent damage to the heater,
building damage, or loss of livestock.
This 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. 21. It is
connected between the ignition control and the gas
control valve.
FIG. 21
HIGH LIMIT SWITCH
The switch has normally closed contacts. If an over-
heat 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
sensing portion on the back of the switch. See Fig.
22. Do not melt the plastic housing of the switch
when conducting this test.
Guardian 2.0 LP or Natural Gas Heater
FIG. 22
RESET BUTTON
TERMINAL
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.
3. To reset, allow the high limit switch to cool down and push
the red reset button. See Fig. 22.
Motor Relay(AW325)
The motor relay is responsible for supplying power to
one of the motor's leads. It is mounted under the lid
of the control box.
Refer to Fig. 23 for connection of wiring and voltage checks.
FIG. 23
120 VAC FROM IGNITION
CONTROLLER (MOTOR)
Owner's Manual • Guardian 2.0
MOUNTING LEGS
TRANSFORMER
NOT USED
NEUTRAL
120 VAC
TO MOTOR
120 VAC FROM
POWER SUPPLY
19
SENSING
SURFACE
FLAME