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Page 18

3 Cap

Screws

FIGURE 25 - Split Taper
Bushing

2 Push-Off Holes

Motor and Belt Shipping Position for Sizes 2-80, 2-120, 3-180, 3-260 - To
relieve tension on the motor mounting bracket, the belt(s) are taken off the
motor and blower sheaves before shipping. The belt(s) are taped to the blower
shaft to prevent loss or damage during shipment. Install the belt(s) and adjust
for proper belt tension.

Blower Pulley - Size 2-80 and 2-120 systems equipped with 3 and 5 HP mo-
tors with a 15.4" diameter and larger blower pulley or a 7-1/2 HP and larger
motor and all Size 3-180 and 3-260 systems are equipped with a split taper
bushing in the blower pulley. The split taper bushings must be loosened in
order to remove the pulley. Follow these instructions to loosen the bushing.
1) Notice that there are three cap screws in the bushing and two holes

without screws, called push-off holes (See FIGURE 25).

2) Remove the three cap screws.
3) Put two of the cap screws into the two push-off holes. Tighten these two

screws evenly until the pulley is loosened.

4) Pulley may now be removed from the shaft.

Blower Speed Adjustment - Units are set at the factory for the RPM required
to meet the CFM and external static pressure specified on the order. If the
estimated external static is incorrect, or changes are made to the duct system,
the blower RPM may have to be changed. Motors are equipped with adjust-
able pitch pulleys which permit adjustment of blower speed. Instructions are
included in Paragraph 13, Check-Test-Start for adjusting blower speed.
Blower Rotation - Each blower housing is marked for proper rotation. In-
structions for checking blower rotation are included in the Check-Test-Start
Procedure in Paragraph 13.
Motor Loads - Use an ammeter to check motor amps. Amps may be adjusted
downward by reducing blower RPM or by increasing duct system static pres-
sure. For accurate amps, read the motor manufacturer's rating plate; amps will
vary depending upon motor manufacturer. The chart below can be used for
sizing line wiring.

Gas Pressure
Switches

High gas pressure switches included in the gas train monitor gas pressure
downstream from the safety valves. If the gas pressure at this point on a sys-
tem equipped with a high gas pressure switch (standard with Manifolds BM
78, 79, 80, and 81 or Option BP2 with other manifolds) exceeds the setpoint,
the switch will open the electrical circuit to the burner, stopping all gas flow.
The high gas pressure switch is a manual reset device.
A low gas pressure switch (Option BP3) will shutoff the gas flow if the gas
pressure drops below the setpoint of the low pressure switch. The low gas
pressure switch will automatically reset when the gas pressure rises above the
setpoint.
(NOTE: Model RDF units manufactured prior to April 1993 installed indoors
with optional gas pressure switches require a 3/4" vent line to the outdoors.
Beginning with units manufactured April 1993, the gas pressure switches in-
corporate a vent limiting device and do not require venting to the outdoors.)

12. Blowers,

Drives, and
Motors

Belt Tension - Check belt tension. Proper belt tension is important to the long
life of the belt and motor. A loose belt will cause wear and slippage. Too much
tension will cause excessive motor and blower bearing wear. If adjustment is
required, adjust belt tension by means of the adjusting screw on the motor
base until the belt can be depressed 1/2" to 3/4" (FIGURE 24). Tighten the
lock nut on the adjusting screw. Be sure the belt is aligned in the pulleys.

3/4” (19mm)

FIGURE 24 - Belt Tension

11. Gas Piping

and
Pressures
(cont'd)

Summary of Contents for RDF 1-20-3

Page 1: ...tem provides tempered makeup air Makeup air is defined as air that enters a building or area due to negative pressure created by an air exhaust load in excess of the volume of entering air This system...

Page 2: ...account through standard engineering methods the structure s designed infiltration rate by providing properly sized relief openings by interlocking a powered exhaust system or by a combination of thes...

Page 3: ...e Sensor Option AR32 Toggle Switch Option AR36 Photohelic Pressure Sensor Option AR37 Photohelic Pressure Sensor If an optional remote console is ordered these controls are mounted on the console The...

Page 4: ...al to the width of the unit Top View Control Side Front View Rear View A Full Length of Outside of Curb Cap D Inside of Curb Cap Z Y B Cabinet Height 2 5 8 67 Control Compartment Blower Compartment Su...

Page 5: ...88 37 1 8 44 3 16 84 13 16 45 1 2 24 1 2 10 1 2 5 7 16 14 9 32 15 5 8 21 29 32 19 1 8 2 80 3 2 120 3 88 48 11 16 68 1 4 84 13 16 69 1 2 52 16 1 4 5 5 16 10 15 16 15 1 2 27 9 32 27 7 32 3 180 3 3 260...

Page 6: ...placed directly on a surface cross supports should be placed underneath the rails at the ends and at the cabinet joint Refer to FIGURE 4 IMPORTANT NOTE Mount an outdoor unit with a minimum of 14 clear...

Page 7: ...8 1 7 8 48 1 7 8 48 Roof Curb Ductwork for Bottom Discharge Option AQ1 or AQ3 Roof Curb Ductwork for Optional Return Air Airflow See IMPORTANT NOTE on the left Roof Curb Dimensions for Model RDF Serie...

Page 8: ...tolerance of 1 8 5 Level the roof curb To ensure a good weatherproof seal between the unit curb cap and the roof curb the roof curb must be leveled in both direc tions with no twist end to end Shim as...

Page 9: ...system is automatically controlled to maintain a set building pressure the en tering air will travel naturally toward the relief areas at the perimeter walls using the building structure as the distr...

Page 10: ...the type of construction of the roof wood joist steelbar joist steel truss pre cast concrete etc and the ceiling hung flush etc o Rectangular ducts should be constructed of not lighter than No 26 U S...

Page 11: ...er Light and Potentiometer If ordered the optional remote console is shipped separately Re mote consoles include terminal blocks for wiring Depending on what gas control or inlet air options were orde...

Page 12: ...normally open differential pressure switch that senses air pressure across the filter bank There are field installation procedures that must be done for the proper operation of the dirty filter indic...

Page 13: ...valve will not open If the actual temperature of the outside air is above the setpoint on the outside air control the burner will not ignite may modulate to satisfy discharge setting would shutdown co...

Page 14: ...t this switch The pressure null switch is Dwyer 1460 0 with a range of 01 12 w c The pressure null switch is a diaphragm operated differential pressure switch used in makeup air applications to contro...

Page 15: ...n AR33 or AR34 and or with Gas Control Option AG37 or AG51 If the system includes Air Control Option AR33 the discharge damper is con trolled by a field supplied 0 10VDC or 4 20 milliamp signal If the...

Page 16: ...dance with the requirements of the National Fuel Gas Code ANSI Z223 1 latest edition or CAN1 B149 1 and B149 2 Gas supply piping installation must conform with good practice and with all local codes R...

Page 17: ...te on a natural gas pilot supply pressure of 3 5 w c or propane gas of 6 0 w c Measure both operating pressure and pilot supply pressure with the blower in operation Manifold pressure is defined as th...

Page 18: ...ocedure in Paragraph 13 Motor Loads Use an ammeter to check motor amps Amps may be adjusted downward by reducing blower RPM or by increasing duct system static pres sure For accurate amps read the mot...

Page 19: ...k Test Start FIGURE 26 Control Locations in the Electrical Compartment RDF Series 3 Direct Fired Systems NOTE Locations may not be identical but controls should be smilar Check Test Startup Procedures...

Page 20: ...oIf equipped with any manually reset devices such as an optional firestat limit switch a high limit switch and or optional high gas pressure switch reset devices Check setpoint on the high ambient bu...

Page 21: ...oosen the setscrew on the side of the pulley away from the motor c Turn adjustable half of the pulley inward to increase blower speed One turn of the pulley will change speed 8 to 10 d Tighten the set...

Page 22: ...er 2 Model No AG3 Two Stage with Two Stage Ductstat MV 7 Serial No AG30 orAG31 Maxitrol Series 14 Outside Air Only Amplifier A1014 MV 8 Serial No AG32 Maxitrol Series 14A Outside Air Only Amplifier A1...

Page 23: ...k the main burner inlet gas pressure If the main inlet gas pressure is lower than stated on the rating plate full burner firing rate will not be achieved Check main gas supply service regulator for ad...

Page 24: ...irements in the installation codes and operating instructions The amount of air over the burner must be within the specified range The burner profile plates are set at the factory to match CFM require...

Page 25: ...ate N A 2 91584 2 98764 Filter Block Off Sections N A 6 95335 6 96335 Permanent Filters 12 N A 1 87251 2 94383 Sheetmetal Screws 10 x 1 2 long Screws 1 4 20 x 5 8 long bolt type Hex Nuts 1 4 20 Keps S...

Page 26: ...inet Post Bottom Filter Channel with Blockoff Plate assembled in 1B P N 91578 Intermediate Cabinet Post Center Channel Assy Step 1C Assemble Outer Side of Filter Rack Options AS6 and AS7 only Parts Re...

Page 27: ...tach Assembled Cabinet Section 4 Assemble Air Inlet Hood Section P N 91569 Right Side of Hood P N 91568 Left Side of Hood Step 4A Attach Hood Sides Attach the sides to the interme diate posts and bott...

Page 28: ...er Louver Supports Step 4E Install Louvers Parts Required Two factory assembled louver sec tions 19 screws 1 2 long and five Tinnerman clips Position one louver section in the left side of the hood at...

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