Direct Drive Blower Guide for Residential and Commercial Furnace Blowers and Fans

BLOWER INSTALLATION, ADJUSTMENT and SERVICE GUIDE for DIRECT DRIVE BLOWERS

Direct Drive Blowers

A GOOD INSTALLATION PAYS OFF ...

for you and your homeowner. Here are four simple steps to follow for trouble-free installation.

1. BEGIN BY MOUNTING BLOWER FEET....

Feet can be mounted in any of four standard positions by using the slotted holes and screw holes in the housing sides. Any variation in position may be easily obtained by trimming off the tabs and drilling new screw holes. The hardware bag contains rubber Vibro-Pads. Slip one into each of the corner holes of the feet.

2. MOUNT VARIABLE MOTOR SPEED CONTROLLER ...

to the blower housing or remotely on the unit. Finger tip control gives an infinite number of motor speeds. Wire to the blower motor by following diagram (A), below. Use a capacitor when PSC motors larger than 1/4 hp are used. See wiring diagram (B).

Click on Image for Larger Version

3.INSTALL THE BLOWER... in the furnace or air conditioning unit following this checklist.

	Center and seal the blower outlet in the blower opening of the unit, so that there is no air leakage,
	Support the blower by its mounting feet. Avoid metal-to-metal contact.
	Wire the motor according to the diagram supplied with the unit, or its control, following all local codes.
	Anchor the wiring with resilient clips to keep it from rattling or transmitting vibration noises.

4. ADJUST BLOWER SPEED...

with a clean rag to get rid of oil and dirt. Dirt and grease are tough abrasives that cause the belt to wear out faster, throwing it out of balance and shortening its life.

PREVENTATIVE MAINTENANCE FOR DIRECT DRIVE BLOWERS

Show the homeowner how they can perform basic service on the blower:

	Oil the motor seasonally with medium weight (SAE 20) motor oil.
	Vacuum the blower and blower compartment seasonally.
	Change filters seasonally and replace when dirty.

CHECKLIST FOR BOTH BLOWERS:	Belt Drive	Direct Drive
Pulleys...Be sure they are tight on their shafts and are in line.	X
Belt...If worn, replace it after determining and correcting the cause of wear (i.e. belt to loose, belt too tight, pulleys not in line, shafts not parallel, dirt and grease on belt and pulleys, etc.)	X
*Electrical Connections...*Be sure lead cable is resiliently anchored and cannot rattle or transmit vibrations.	X	X
*Blower Outlet...*See that the outlet is centered in the blower opening of the unit and sealed against air leakage.	X	X
*Noise...*Make sure there is no metal-to-metal contact.	X	X
*Blower Bearings...*Worn bearings mean trouble. Replace bearings and shaft if necessary.	X
*Wheel...*See that the wheel is centered in the blower housing and that the thrust collars are tight on the shaft.	X	X
*Lubrication...*Oil the motor and blower bearings, if needed.	X
Filters...Filters should be replaced at the beginning of each season and should be changed during the season.	X	X

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BLOWER SPEED ADJUSTMENT AND INSTALLATION TIPS

BELT DRIVE...

Loosen the setscrew on the outer face of the variable pitch moor pulley and turn the face. The speed is reduced by turning the outer face to move the two pulley faces further apart. The speed is increased by turning the outer face to move the faces closer together. Be sure to retighten the setscrew against the flat spot on the pulley hub after adjusting the speed of the blower. Readjust the belt tension and align the belt and pulleys.

DIRECT DRIVE...

The finger-tip control on the top of the Variable Motor Speed Controller adjusts the voltage of the motor, controlling its speed.

ALL BLOWERS...

Install the filters in the unit before running the blower, especially during new home construction. If the unit is not equipped with filters, protect the blower and motor from airborne dust and dirt by fitting standard furnace filters on the return air side of the unit, until construction is completed. All units should have filters, which trap abrasive dirt that could cause damage to the blower bearings and motor.

In a forced warm air furnace, use this procedure to obtain a recommended heat-rise of about 90ºF (unless otherwise specified by the manufacturer).

Place one thermometer in the return air plenum and one in the warm air plenum. After the temperature of the warm air side has leveled off with the blower and burner running, compare the reading of the two thermometers. If the difference is less than 90ºF, slow down the blower speed. If it is more, increase the blower speed. Keep adjusting until a rise of approximately 90ºF is maintained.

In an air conditioning unit, use a 20ºF drop instead of the 90ºF rise specified above for heating purposes (unless otherwise specified by the manufacturer of the unit). The air delivery should be sufficient to keep the coils from frosting and the refrigerant suction pressure from rising.