Fume Exhaust Fans
9
NOTE
On the model VJI, the plug needs to be removed from
threaded drain connection regardless of plans to pipe
and trap.
Fan Drainage Piping and Trap Detail
(by others)
Fans have been supplied with a drain. Drains are
located at the underside of the scroll housing. The drain
may need to be connected to a drainage system to
ensure proper disposal of any water or condensate that
may occur.
• Drain connections are 1.0 inch MNPT (model VJI)
•
Installed piping to have a downward angle to allow
for drainage
•
Fill traps to recommended level before start-up
Note:
A conservative method of trap design is to set
N = total static pressure.
Check local codes for proper disposal of drain water
which has been in contact with the exhaust air.
Positive Pressure Trap
N = Negative fan pressure (inches W.C.)
H = N - 0.5 inches minimum
H/2
H/2
H
1.25 inch
minimum
N
FAN ON
FAN OFF
Connect
this end
to fan drain.
The adjustable motor pulley is set at the factory for
the fan RPM specified by the customer. Fan RPM can
be increased by closing or decreased by opening the
adjustable motor pulley. Multigroove variable pitch
pulleys must be adjusted an equal number of turns
open or closed. Any increase in fan speed represents a
substantial increase in load on the motor.
To avoid motor overheating and possible burnout, motor
load amperes should always be checked and compared
to nameplate rating when fan speed is increased.
Alignment of Pulleys and Belts
Check pulleys and belts for proper alignment to avoid
unnecessary belt wear, noise, vibration and power loss.
Motor and drive shafts must be parallel and pulleys in
line as shown in Figure 1.
CORRECT
WRONG
WRONG
WRONG
Figure 1
V-Belt Drives
V-Belt Drive Installation
1. Remove the protective coating from the end of the
fan shaft using mineral spirits or another similar
solvent. Check to ensure that the shaft is free of
nicks and burrs.
2. Slide sheaves on shafts. Do not drive
sheaves on as this may result in
bearing damage.
3. Align fan and motor sheaves
with a straight edge or string
and tighten.
4. Place belts over sheaves.
Do not pry or force belts, as
this could result in damage
to the cords in the belts.
5. Adjust the tension until the
belts appear snug. Run the
unit for a few minutes and allow the belts to “Set”
properly.
6. With the fan off and disconnect locked out, adjust
the belt tension by moving the motor pivot plate.
When in operation, the tight side of the belts should
be in a straight line from sheave to sheave with a
slight bow on the slack side.
Aligning Sheaves with
a Straight Edge
