Reznor CAUA Unit Installation Manual - Manual (Page 30)

Form I-CAUA, P/N 164771 R8, Page 30
6.0 Mechanical
(cont'd)
Direct Drive Motors
TABLE 22 - Direct Drive
Motor Wiring
CAUA
Sizes
Speed
Use these
two motor
wires:
150, 200,
250, and
350
High
White and
Black
Medium White and
Black
300 and
400
High
White and
Black
Medium White and
Black
Belt drives have an adjustable pulley which permits adjustment of the blower speed.
Follow these instructions to adjust blower speed of a belt drive motor. ( NOTE: These
instructions apply only to a belt drive motor that is not equipped with an optional vari-
able frequency drive.)
1. Turn off the gas and the electric power.
2. Loosen belt tension and remove the belt.
3. Loosen the set screw on the side of the pulley away from the motor.
4.
To increase the blower speed, turn the adjustable half of the pulley inward. To
decrease the blower speed, turn the adjustable half of the pulley outward. One
turn of the pulley will change the speed 8-10%.
5. Tighten the set screw on the flat portion of the pulley shaft.
6. Replace the belt and adjust the belt tension. Adjust tension by turning the adjusting
screw on the motor base until the belt can be depressed 3/4". (See FIGURE 23.)
Re-tighten the lock nut on the adjusting screw. Be sure that the belts are aligned in
the pulley grooves properly and are not angled from pulley to pulley.
7. Turn on the gas and electric. Light the heater following the instructions on the light-
ing instruction plate.
8. Check the motor amps with an amp meter. The maximum motor amp rating on the
motor nameplate must not be exceeded.
When service is complete, check for proper operation.
When an optional variable frequency drive is ordered, the motor operates on two
speeds as determined by the electrical frequency. High speed is used for cooling and
low speed for heating. 60 hertz is the maximum high speed. Maximum speed for low
speed heating is the frequency that will provide the maximum temperature rise of the
heater. Allowable temperature rise range for a Model CAUA heater is 45-75°F.
Follow the variable frequency controller manufacturer's instructions that are packaged
with the heater (in the owner's envelope) to program the variable frequency drive set-
tings.
Belt Drive Motors
If the duct resistance is low, the blower may deliver too high an air volume. If the resis-
tance is very low, the blower may deliver excess air to overload the motor, causing the
overload protector to activate. Reducing the blower speed will correct these conditions.
If ductwork is added to an installation, it may be necessary to increase the blower
speed.
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 the
blower speed or by increasing the duct system static pressure. The temperature rise
must be within the range specified on the unit rating plate.
Direct drive motors have multi-speed taps for speed adjustment. If your installation
requires an adjustment of the blower speed, the motor may be re-wired to an alternate
tap by following these instructions.
1. Turn off the gas and electric power.
2. Remove the blower door panel.
3. Consult the wiring diagram on the heater and follow the chart in TABLE 22 to
choose the wiring for the desired adjustment. Units are wired at high speed for
cooling (if ordered) and medium speed for heating.
4. Cut the crimped cap for the end of the wire that you intend to use and strip the
insulation.
5. Disconnect the factory-wired connection and rewire using the newly stripped wire.
6. Put a wire nut on the end of the blower motor wire that was disconnected.
7. Replace the heater door panel. Turn on the gas and electric. Check for proper
operation.
6.5 Blower, Motor,
and Drive
(cont'd)
Belt Drive with Optional
Variable Frequency
Drive
Adjusting Blower Speed (cont'd)