L.B. White Pilot - Manual (Page 52)

High Limit Switch Tests
Component
Testing
6.4-1 1
August 1999
Method oof TTest:
Disconnect the heater from its electrical supply before
conducting this test.
Remove the switch from its location. Hold the switch by one
of its legs with a pliers and apply a small flame only to the
sensing portion on the back side of the switch. Be careful
not to melt the plastic housing of the switch when
conducting this test. Within 1 minute, you should hear a
“pop” coming from the switch which indicates the electrical
contacts have opened.
Let the switch cool down for about 10 - 20 seconds before
firmly pressing the reset button on the switch. Check for
continuity across the terminals of the switch to make sure
the contacts are closed.
Reinstall the switch into the heater and reconnect heater to
its electrical supply.
ATTENTION
Model AB200 heaters incorporate a high limit switch with a
sensing capillary. To test this switch, run a small flame back
and forth along a 6 inch section of the capillary. Within 1
minute the electrical contacts of the switch should open.
You may leave the switch in mounted position to perform the
test.