Final Start Up Procedure
1.With the air and burner systems in full operation and all ducts attached, measure the system airflow. Motor sheave (pulley) is variable pitch, and allows for an increase or decrease of the fan RPM to adjust the airflow, as shown in the illustration below. For your convenience, a RPM chart is included in the following pages.
2.Once the proper airflow is achieved, measure and record the fan speed with a reliable tachometer. Caution - Excessive speed will result in motor overloading or bearing failure. Do not set fan RPMs higher than specified in the maximum RPM chart. See the troubleshooting guide for more information.
3.Measure and record the voltage and amperage to the motor and compare with the motor nameplate to determine if the motor is operating under safe load condition.
4.Once the rpm of the ventilator has been properly set, disconnect power and recheck belt tension and pulley alignment as described below.
Maximum RPM and HP Chart | Pulley Adjustment Illustration | ||
Blower Size | Maximum RPM | Maximum HP |
|
10” | 1800 | 2 |
|
12” | 1500 | 3 |
|
15” | 1400 | 5 |
|
18” | 1200 | 5 |
|
20” | 1000 | 10 |
|
25” | 900 | 20 |
|
Pulley Adjustment
The adjustable motor pulley is factory set for the RPM specified. Speed can be increased by closing or decreased by opening the adjustable motor sheave. Two groove variable pitch pulleys must be adjusted an equal number of turns open or closed. Any increase in speed represents a substantial increase in horsepower required by the unit. Motor amperage should always be checked to avoid serious damage to the motor when the speed is varied. Always torque setscrews according to the setscrew torque chart.
Setscrew Torque
Thread Size | Torque (IN/Lb) |
No. 10 | 33 |
1/4” | 80 |
5/16” | 156 |
3/8” | 275 |
7/17” | 384 |
1/2” | 600 |
Pulley Alignment | Proper Belt Tension |
13
