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1. Blowers should be mounted on the roof in-order that

the ducting leading to the blower inlet is under negative

static pressure. If exhaust blowers are mounted inside

the building, all ducting connected to the blower outlet

will be under positive static pressure, if a leak were to

develop in the section of the duct inside the building,

toxic and or hazardous fumes could be forced out of

the ductwork and into that area of the building.

2. To achieve the lowest practical noise level in the

exhaust system, we suggest that the following

measurements be used when there is no conflict

with other specifications of the system:

a. Use vibration isolators or mounting blower exhaust

assembly.

b. Install a blower fan that will deliver the correct CFM

and static pressure with the lowest practical impeller

wheel RPM. If possible, use a duct size large enough

to keep duct velocity under 1800 FPM velocity.

c. Use a flexible connection at the fan inlet to isolate

mechanical transmission of noise from the ducting

between the hood and the exhaust blower.

d. Exhaust blower system should be designed with the

fewest possible elbows or other fittings. Use radius

type elbows & avoid using square elbows. Use

gradual tapered transitions where necessary, & avoid

abrupt changes in configuration or cross sectional area.

3. When ordering an exhaust blower, specify the

orientation of discharge desired. Vertical up blast

discharge is the most common and will be supplied unless otherwise specified.

4. All fans are shipped with clockwise rotation when viewed from the motor end of the assembly.

5. For normal usage, the standard for both the blower housing and impeller wheel is epoxy coated.

6. Blowers used for hood exhaust at altitudes above

1,000 feet, may require a correction factor to

provide the correct CFM and static pressure.

Motor speed control can be used to manually adjust blower cfm. Adjustable speed control for 3-phase motors 3/4 to 10 horsepower at 230/460 volts and 50/60Hz. these drives provide high operation efficiency and constant input power factor throughout the entire speed range of 3 to 60Hz. Drives are rugged, reliable and backed by years of manufacturing and application experience in motors and controls. These drives are tailored to the variable torque loads in fans or fume hoods.1/2 -5HP 230V 3ph, 50/60Hz................................................Cat.No. 51402