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B.
Replacing the Temperature High-Limit Cutouts:
1.
Disconnect the heater electrical power supply
and remove the heater enclosure cover.
2.
Remove the wire barrier to expose the high
limit cutout.
3.
Disconnect the wires from the high limit
cutout and mark their location.
4.
Remove the two nuts used to attach the
temperature high limit cutout.
5.
Lift and remove the sheetmetal mounting
plate.
6.
Carefully lift and remove the temperature high
limit cutout.
7.
Use only factory supply parts for safe
operation.
8.
Lightly coat the new manual and automatic
cutout bulbs with the supplied thermal transfer
compound. This is critical for proper cutout
operation.
9.
Carefully slide the automatic cutout bulb into
the
left
thermowell and the manual cutout bulb
into the
right
thermowell.
10.
Reinstall the sheetmetal plate. Note that the
sheetmetal plate also acts as a stop to keep the
cutout bulbs from backing out of the wells.
11.
Carefully install the temperature high limit
control to avoid putting kinks into the
capillary.
12.
Reattach the wires to the cutout and reinstall
the wire barrier.
13.
Ensure heater enclosure cover is in place
before energizing heater.
C.
Resetting the Manual Cutout:
All unit heaters contain a built-in manual reset
thermal cutout with or without backup contactor.
1.
Disconnect the heater electrical power supply
and remove the heater enclosure cover.
2.
Determine the reason for the manual reset
thermal cutout actuating and rectify the
situation. See section titled “maintenance”.
3.
Reset the manual reset thermal cutout by
pressing on the red stem in the center of the
control.
4.
Replace the heater enclosure cover securely.
5.
Energize the heater electrical supply circuit.
6.
The heater and fan should come on and in 5 to
15 minutes reach a stable operating
temperature.
7.
Check out and report any unusual or
questionable operating characteristics, such as
noise, vibration, loss of fluid, etc.
8.
If heater operation appears normal, place the
unit into normal operation.
D.
Replacing the Fan Motor and Blade:
The fan motor is permanently lubricated and does not
require any maintenance. If the fan motor is
defective, a replacement must be obtained from the
factory.
1.
To replace the fan motor:
a.
Disconnect the heater electrical power
supply.
b.
Disconnect the motor supply wires from
the contactor in the wiring enclosure.
c.
Disassemble the conduit union located at
the motor wiring hub.
d.
Remove top fan guard and motor
mounting bolts.
e.
Lift motor out of heater assembly.
f.
Remove fan blade and conduit union from
defective motor and install on new motor.
g.
Install new motor to heater using existing
motor mounting hardware.
h.
Reinstall top fan guard and ensure that the
fan blade rotates freely.
i.
Feed motor wires through conduit and
into wiring enclosure.
j.
Reattach conduit union. Reconnect motor
wires to contactor.
k.
Check fan rotation by momentarily
energizing heater. Airflow should exit
from front of heater cabinet. If rotation is
incorrect, disconnect electrical power
supply and reverse two of the motor lead
wires at the contactor.
l.
Reattach wiring enclosure cover before
placing heater back in service.
2.
To replace the motor fan blade:
a.
Remove the top fan guard.
b.
Remove the four motor mounting bolts
and disconnect the conduit union at the
motor.
c.
Loosen the bolt that connects the fan
blade to the motor shaft.
d.
Slide the motor back and tilt in order to
remove the old blade & install a new one.
e.
Tighten the fan blade attachment bolt to
the motor shaft.
f.
Reattach the motor conduit union and the
four motor mounting bolts.
g.
Reinstall the top fan guard and ensure that
the fan blade rotates freely.
