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Form 436, Page 16
13. Fan Motor
Fan motors are equipped with thermal overload protection of the auto-
matic reset type. Should the motor refuse to run, it may be because of
improper current characteristics. Make certain that the correct voltage
is available at the motor.
NOTE: If the unit is equipped with an optional totally enclosed motor,
the horsepower may be larger than the standard motor. Refer to the
motor nameplate to verify horsepower.
14. Blower Motor
Blower Model Sizes 25-100 are standardly equipped with a direct drive
motor; an optional belt drive motor is available on Sizes 50-100. Blower
Model Sizes 125-400 have an adjustable belt drive motor.
As part of the Check/Test/Start (Paragraph 24), check the belt for proper
tension. Proper belt tension is important to the long life of the belt and
motor. A loose belt will cause wear and slippage. Too much tension
will cause excessive motor and blower bearing wear. Adjust the belt
tension by turning the adjusting screw on the motor base until the belt
can be depressed 1/2-3/4". (See Figure 13.) After correct tension is
achieved, re-tighten the locknut on the adjusting screw.
Most blower motors are equipped with thermal overload protection of
the automatic reset type. If a motor is not equipped with thermal over-
load protection, the unit will be equipped with a starter. The adjustable
setting on the starter will be factory set to match the amp draw of the
12. Thermostat Connections (cont'd)
There are some unique wiring requirements with the installation of the optional controls (relay and two-stage). Figure 12 illustrates the wiring of the
relay and the connections required for optional thermostat control.
Multiple Heater Control - These unit heaters are not designed for multiple unit connection to one thermostat. If you require that more than one unit
be controlled by a single thermostat, it will be necessary to use relays in the circuit. Options CL31 and CL32 provide the necessary parts and
instructions for multiple heater control. For more information on these options, see Paragraph 30.
motor and sealed. No change should be made to starter set unless the
original motor is replaced.
Starters are supplied from the factory for manual reset operation. If an
overload condition is experienced, the condition must be corrected,
and the starter must be manually reset.
After the installation is complete including all ductwork, the amp draw
of the motor should be checked with an amp meter to verify that the
motor amp rating on the motor nameplate is not being exceeded. Amps
may be adjusted downward by reducing blower speed for by increas-
ing the duct system static pressure. The temperature rise must be within
the range specified on the unit rating plate.
Figure 13 -
Adjusting Belt
Tension
Figure 12 - Wiring Diagrams for Optional Controls
575/3/60