High Limit Switch; Transformer - L.B. White Guardian AD/AW060 Manuel Du Propriétaire

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 fi re, 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.17.
It is connected between the ignition control and
the gas control valve.
FIG. 17
HIGH LIMIT SWITCH
The switch has normally closed contacts. If an
overheat condition occurs, the switch contacts will
open, thereby opening the circuit to the gas con-
trol 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 fl ame only to
the sensing portion on the back of the switch.
See Fig.18. Do not melt the plastic housing of
the switch when conducting this test.
Guardian LP or Natural Gas Heater
FIG. 18
RESET BUTTON
TERMINAL
MOUNTING
LEG
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.

Transformer

The transformer receives 120 volts and reduces it
to 24 volts. The 24 volts is supplied to the ignition
controller to start the ignition process. See Fig. 19.
-- If 24 volts is not supplied from the transformer to
the ignition controller, the heater will not operate.
FIG. 19
24 VOLT OUTPUT
TERMINAL
Owner's Manual • Guardian
SENSING
SURFACE
FLAME
TRANSFORMER
19