System Start-Up

For proper unit function and safety, follow everything in this start-up procedure in the order presented. This is to be done after the electrical connections are complete.

PRE-START CHECK LIST

1.Disconnect and lock-out all power switches to fan.

2.Check all fasteners, set screws and locking collars on the fan, bearings, drive, motor base and accessories for tightness.

3.Rotate the fan wheel by hand and assure no parts are rubbing.

4.Check the V-belt drive for proper alignment and tension.





Unit Size	G

25 - 50	1/4 inch



65 - 85	3/8 inch
65 - 85	3/8 inch	G

Wheel Overlap Dimensions

special tools required

•Voltage Meter

•Tachometer

•Amperage Meter

1.Check Voltage

Before starting the unit, compare the supplied voltage with the unit’s nameplate voltage and the motor voltage. Units are not provided with thermal overload protection unless a control center has been ordered with the unit or the motor has been selected with thermal overload protection.

2. Check Blower Rotation

A common problem is wheel rotation in the wrong direction. For centrifugal fans, incorrect wheel rotation will provide poor air performance, motor overloading and possible burnout. Rotation should be checked while the fan is coasting to a stop. Proper wheel rotation is shown.

R			R
ot			ot
	a			a
		ti			ti
		o			o
		n			n

BackwardForward

InclinedCurved

Proper Wheel Rotation

When connecting a 3-phase motor, there is a 50% chance that the fan will run backwards. Changing

any two supply power connections will reverse the direction of rotation.

To reverse the rotation, turn the power off and use the following procedure:

•For single phase units, rewire the motor per the instructions on the motor.

•For three phase units, interchange any two power leads. This can be done at the motor starter.

3.Check for Vibration

Check for unusual noise, vibration or overheating of bearings. Excessive vibration may be experienced during initial start-up. Left unchecked, excessive vibration can cause a multitude of problems, including structural and/or component failure. Many conditions can be discovered by careful observation. If the problem is wheel unbalance, in-place balancing can be done providing there is access to the fan wheel. Generally, fan vibration and noise is transmitted

to other parts of the building by the ductwork. To eliminate this undesirable effect, Greenheck has used a heavy canvas connection between the scroll and the discharge of the fan. If noise is an issue, we recommend using heavy canvas connections on the inlet of the fan. Refer to the Troubleshooting section of this manual if a problem develops.

4. Air Volume Check and Measurement

Along with the building balance, the unit’s air volume (cfm) should be measured and compared with its rated air volume. This unit is flexible for varying air volume, but the actual air volume should be known for making final adjustments. The most accurate way to measure the air volume is by using the pitot traverse method in the ductwork away from the blower. Other methods can be used, but should be proven and accurate. To adjust the air volume, change the fan rpm or the system losses. See Troubleshooting section in this guide.

5. Measure Motor Voltage, Amperage and Fan RPM

All access doors must be installed. Measure and record the input voltage and motor amperage(s).

To measure the fan RPM, the blower door will need to be removed. Minimize measurement time because the motor may over amp with the door removed.

Compare measured amps to the motor nameplate full load amps and correct if over amping. See the Troubleshooting section in this guide.

10 Model MSCF Modular Small Cabinet Fan