Manual Reset High Limit Switch - L.B. White Premier 40 Series Owner's Manual And Instructions

20
Premier Ductable Heater
Manual Reset High Limit
Switch
WARNING
Fire Hazard
■ Do not operate the heater with the high limit
switch bypassed.
■ Operating the heater with the high limit switch
bypassed or jumper-ed may lead to overheating,
possibly resulting in a fi re, with subsequent
damage to the heater or property damage.
This heater has one high limit switch; located directly
below the burner on the underside of the heat chamber.
It is easily identifi ed by a red reset button in the center of
the switch. See Figs. 15.
FIG. 15
Function
If the heater overheats, the high limit switch can trip,
opening the electrcial circuit to the gas control valve.
Overheating is generally caused by duct restrictions, low
voltage, blocking the heater's air inlet, or excessive gas
pressure.
Resetting
If the high limit switch trips; remove the red cap and fi rmly
press the reset button in the middle of the switch. Then,
shut the heater off and turn it back on. Determine the
cause of the limit tripping.
Testing
To ensure proper function of this critcal safety
component, test the switch annually, typically when the
heater is given a thorough cleaning.
Owner's Manual • Premier 40
1. Remove the high limit switch from the heater.
2. With a pliers hold the switch by one of its mounting
legs, apply a small, soft fl ame only to the sensing
portion on the back of the switch. See Fig. 16. Be
careful not to melt the plastic housing of the switch
when conducting this test.
3. Within a minute, you should hear a click coming from
the switch, indicating the contacts of the switch have
opened.
4. Allow the switch cool down for about a minute.
Remove the red cap and fi rmly press the reset button
on the switch.
5. Check for electrical continuity across the switch ter-
minals to make sure the contacts have closed. Install
Igniter
the red cap; reinstall back into the heater and connect
the wires to the terminals.
FIG. 16
RESET BUTTON
Burner
High Limit
MOUNTING
LEG
TERMINAL
SENSING
SURFACE
FLAME