Premier Ductable
Heater
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Owner’s Manual •
Premier 350DF 2.0
22
Motor end limit:
Protects from overheating if
the duct is kinked or restricted, or if the air inlet is
blocked.
The switches are wired in series and will discon-
nect power to the gas control valve if either senses
an overheat condition.
Both high limit switches should be tested a mini-
mum of once per year when the heater is given a
thorough cleaning.
1. Remove the high limit switches from the
heater. Also remove the red cap from both
switches.
2. Holding a switch by one of its mounting
legs, apply a small flame only to the
sensing portion on the back of the switch.
See Fig. 30. Be careful not to melt the
plastic housing of the switch when
conducting this test.
FIG. 30
Fan Wheel, Bearings and
Shaft
FIG. 31
Burner Orifice and Gas
Control Valve
Reset Button
Terminal
Sensing
Surface
Shaft flat
Shaft flush
with pulley hub
Pulley hub
Main support
Bearing race flush with front edge of shaft flat.
Set screws tightened to flats.
Fan hub flush with
shaft end
Fan wheel
Flame
Mounting Legs
3. Within a minute, you should hear the contacts of
the switch have opening.
4. Allow the switch to cool for about a minute
before firmly pressing its reset button. Put the red
cap back on the switch.
5. Check for electrical continuity across the switch
terminals to make sure the contacts have closed.
1. Remove the following:
a. Belt guard and belt.
b. Bolts and washers securing the bearing platform
at the heater's base.
c. Screw securing the fan panel to the fan housing.
2. Slide the complete assembly from the heater.
3. Replace the components as needed.
4. When reinstalling, ensure fan shaft is flush with fan hub
and fan pulley. See Fig. 31.
1. Remove hose and pipe nipple from control valve inlet.
2. Open burner end door.
3. Remove the screws from gas control bracket and
disconnect control valve's electrical wiring. See. Fig. 32.
