Comfort-Aire HBH Series 6-10 Tons - Manual (Page 28)

IOM Manual HBH SERIES Heat Controller, Inc.
27
Blower Adjustment
Airflow and External Static Pressure
Selection Adjustment - The TCH Series is available with
standard, low, and high static options. These options will
substitute a different blower drive sheave for each static
range. In addition certain static ranges (bold print in Tables
5a through 5k) may require the optional large fan motor.
Please specify static range and motor horsepower when
ordering. See model nomenclature.
Sheave Adjustment - The TCH Series is supplied with
variable sheave drive on the fan motor to adjust for
differing airflows at various ESP conditions. Select an
airflow requirement on the left side of the table, then move
horizontally to right under the required ESP. Note the
sheave turns open, rpm and horsepower for that condition.
Fully closed the sheave will produce the highest static
capability (higher rpm). To adjust sheave position: loosen
belt tension and remove belt, loosen set screw on variable
sheave (on fan motor) and open sheave to desired
position. Retighten set screw and replace belt and set belt
tension as below.
Belt Tensioning - An overly loose belt will, upon motor
start, produce a slippage 'squeel' and cause premature
belt failure and or intermittent airflow. An overly tight belt
can cause premature motor or blower bearing failure.
Belt Tensioning Procedure - HBH
1. Remove belt from motor sheave
2. Lift motor assembly
3. Loosen the 5/16" hex nuts on the grommet motor
adjustment bolts (2 per bolt). To increase the
belt tension loosen the top hex nut. To decrease
the belt tension loosen the bottom hex nut.
4. Turn the bolts by hand to the desired position
then tighten the 5/16" hex nuts ( 2 per bolt).
5. Lower the motor assembly
6. Install the belt
7. The belt should be tensioned tensioning gauge
method such as the Browning Belt Tensioner to
set proper belt tension (See next page).
Notes:
- Motor position should not need adjustment.
- Motor sheave position is at mid position of each
sheave. Thus the motor sheave is typically 2.5
turns open on a 5 turn sheave.
Special Note for AHRI Testing
The Units should be adjusted as follows for rated airflow:
HBH072 - 2400cfm/2.5 turns and 0.57 in wg ESP
HBH096 - 3200cfm/3.0 turns and 0.62 in wg ESP
HBH120 - 4000cfm/3.0 turns and 0.59 in wg ESP
� CAUTION! �
Always disconnect all power supply(s) to unit prior to
making belt or sheave adjustments. Inadvertently starting
of the motor can cause damage to the equipment and
personal injury.
CAUTION!
! !