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Fan rpm, Vibration, Hot gas bypass valve (standard scroll) – Greenheck ERCH (476054) User Manual

Page 34: Belt drive installation, Direction of fan wheel rotation, Warning

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General Description - NOT model specific

Model ERCH Energy Recovery Ventilator

®

34

Belt Drive Installation

1. Remove the protective coating from the

end of the fan shaft and assure that it is
free of nicks and burrs.

2. Check fan and motor shafts for parallel

and angular alignment.

3. Slide sheaves on shafts. Do not drive

sheaves on as this may result in bearing
damage.

4. Align fan and motor sheaves with a

straightedge to centerline.

5. Place belts over sheaves. Do not pry

or force belts, as this could result in
damage to the cords in the belts.

6. With the fan off, adjust the belt tension

by moving the motor base. (See belt
tensioning procedures in the Routine
Maintenance section of this manual).
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.

WRONG

WRONG

WRONG

CORRECT

Proper alignment of motor and drive shaft.

Direction of Fan Wheel Rotation

Blower access is labeled on unit.
Check for proper wheel rotation
by momentarily energizing the
fan. Rotation is determined
by viewing the wheel from the
drive side and should match the
rotation decal affixed to the fan
housing.

If the wheel is rotating the wrong
way, direction can be reversed
by interchanging any two of the
three electrical leads.

Check

for unusual noise, vibration, or
overheating of bearings. Refer to
the Troubleshooting section of this
manual if a problem develops.

Fan RPM

Supply fan and exhaust fan will have an adjustable
motor pulley (on 15 HP and below) preset at the factory
to the customer-specified RPM. Fan speed can be
increased or decreased by adjusting the pitch diameter
of the motor pulley. Multi-groove 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. Always check
the motor amperage reading and compare it to the

amperage rating shown on the motor nameplate when
changing fan RPM. All access doors must be installed
except the control center door.

WARNING

Do not operate units with access doors open or
without proper ductwork in place as the fan motors
will overload.

Model

Blower Diameter

x Width

(inches)

Maximum RPM for

Forward-Curved Blowers

Class I

Max RPM

Class II

Max RPM

ERCH-20

10 x 6

1700

--

9 x 9

1750

2800

ERCH-45

9 x 9

1750

2800

12 x 8

1400

2000

12 x 12

1500

2000

ERCH-55

12 x 12

1500

2000

15 x 15

1250

1725

ERCH-90

15 x 15

1250

1725

18 x 18

1000

1450

Vibration

Excessive vibration may be experienced during initial
start-up and can cause a multitude of problems,
including structural and/or component failure.

Many of these conditions can be discovered by careful
observation. Refer to the Troubleshooting section of

this manual for corrective
actions. If observation
cannot locate the source
of vibration, a qualified
technician using vibration
analysis equipment

should be consulted. If the problem is wheel unbalance,
in-place balancing can be done.

Generally, fan vibration and noise is transmitted to other
parts of the building by the ductwork. To eliminate this
undesirable effect, the use of heavy canvas connectors
is recommended.

Hot Gas Bypass Valve (standard scroll)

To adjust, connect a pressure gauge to the suction line
and block the entering air to the evaporator coil. The
valve should begin to open when the suction pressure
drops to approximately 115 PSIG for R-410A (the valve
will feel warm to the touch). Adjustments are made by
first removing the cap on the bottom of the valve and
then turning the adjusting stem clockwise to increase
the setting pressure (counterclockwise to decrease).
Allow several minutes between adjustments for the
system to stabilize. When adjustment is complete,
replace the cap on the valve.

2 in.

1.5 in.

0.25 in.

centerline

straightedge

Pulley

alignment

example

Vibration Causes

Off axis or loose components
Drive component unbalance
Poor inlet / outlet conditions
Foundation stiffness

Airflow

R

o

ta

ti

o

n

Forward Curved

Rotation

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