Testing The Manual Reset High Limit Switches; Burner Orifice And Gas Control Valve - L.B. White Premier TS170 Owner's Manual And Instructions

Fire H H azard
■
Do not operate the heater with the high limit switch
bypassed.
■
Operating the heater bypassed high limit switch may
lead to overheating, possibly resulting in a fire, with
subsequent damage to the heater or property damage.
This heater has two limit switches, One on the heat
chamber, the other on the fan housing. Both switches
should be tested annually, typically when the heater is given
a thorough cleaning.
1. Remove either high limit switch.
2. Holding the switch by one of its mounting legs, apply
a small flame only to the sensing portion on the back
of the switch. Be careful not to melt the plastic
housing of the switch when conducting this test.
3. Within a minute, you should hear a "pop" coming
from the switch, indicating the contacts of the switch
have opened.
1. Open the burner end access doorand remove gas
hose from heater.
2. Remove the elbow and two screws at inlet of gas
control valve. See Fig. 20.
FIG. 20
SCREWS
4. Disconnect gas control valve's electrical leads.
5. Remove burner retaining bolt, and washer at
underside of heater's base. See Fig. 21. For model
TS080, also remove spacer between heater base
and burner. See Fig. 22.
FIG. 21

TESTING THE MANUAL RESET HIGH LIMIT SWITCHES

WARNING
BOLT
4. Allow the switch cool down for about a minute before
firmly pressing the reset button on the switch.
5. Check for electrical continuity across the switch
terminals to make sure the contacts have closed.
FIG. 19
RESET BUTTON
TERMINAL
MOUNTING
LEG

BURNER ORIFICE AND GAS CONTROL VALVE

FIG. 22
6. Pivot the gas control assembly to expose burner
orifice. See Fig. 23. Replace components as
needed.
FIG. 23
CONTROL
VALVE
SENSING
SURFACE
FLAME
SPACER
ORIFICE
18