Reznor RDF 1-20-3 User manual

Form I-RDF, P/N 148384 (Rev 1), Page 1
Indoor or Outdoor, Gas, Direct-Fired
Makeup Air/Heating Systems
(Specifications subject to change without notice.)
Installation Form RZ-NA I-RDF
Obsoletes Form RZ-NA 440 (Version B)
WARNING: The use and storage of gasoline or other flammable
vapors and liquids in the vicinity of this appliance is hazardous.
FORYOURSAFETY
If you smell gas:
1.Openwindows.
2. Don't touch electrical switches.
3. Extinguish any open flame.
4. Immediately call your gas supplier.
WARNING: Improper installation, adjustment, alteration,
service, or maintenance can cause property damage, injury or
death. Read the installation, operation, and maintenance
instructions thoroughly before installing or servicing this
equipment.
WARNING: Gas-fired appliances are not designed for use in
hazardous atmospheres containing flammable vapors or
combustible dust, or atmospheres containing chlorinated or
halogenated hydrocarbons. See Hazard Levels, page 2.
WARNING: On makeup air heaters which also recirculate room
air, outside ventilation air must be provided in accordance with
the information shown on the heater nameplate.
Recirculation of room air may be hazardous in the presence of:
(a) Flammable solids, liquids, and gases;
(b) Explosive materials; or
(c) Substances which may become toxic when exposed to heat.
General Description
The information in this manual applies to Reznor®Model RDF Series 3 direct-
fired makeup air heating systems. The typical system consists of a direct-fired,
natural gas-fueled burner, and a draw-through blower housed in a weatherized
cabinet. The system may be installed either indoors or outdoors.
This direct-fired makeup air system 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 warms the outside air and monitors the volume and temperature of the
makeup air added to the building. The system may be used to provide ventila-
tion in whole building or in spot applications. In whole building applications,
adding controlled makeup air will cause less infiltration of dust and dirt; will
eliminate continuous backdraft in chimneys and vents; and will reduce space
heating fuel costs.
Applies to: Reznor® Mo el RDF Series 3
Index .................................... Page
Belt Tension ........................................ 18
Blower Rotation ............................. 18
Blower Speed Adjustment ................. 18
Clearances ............................................. 4
Installation Codes ................................. 2
Computer Control (Field)................... 15
Control Locations................................ 19
Control Wiring.................................... 10
Convenience Outlet (Option)............ 11
General Description ............................. 1
Dimensions............................................ 4
Dirty Filter Switch (Option) ............... 11
Discharge Sensor (Option)................. 13
Discharge Temperature
Low Limit (Freezestat Option) ....... 16
Disconnect Switch ............................... 10
Door Switch (Option) ......................... 13
Ductwork Sizing and Installation ..... 10
Electrical Supply and Connections .... 9
Filter Cabinets (Option) ................ 5, 24
Firestat (Option) .................................. 14
Gas Piping and Pressures................... 16
HAZARD INTENSITY LEVELS ...... 3
Maintenance
............... See Form O-DV/RDF/ADF
Makeup Air ............................................ 9
Manifold Pressure ............................... 16
Motor Loads ....................................... 18
Mounting............................................... 6
Operation
............... See Form O-DV/RDF/ADF
Outside Air Cutoff (Option) ............... 13
Outside Air Hoods (Option) ......... 5, 24
Photohelic Pressure Switch (Opt) ...... 15
Potentiometer (Option)....................... 14
Recirculation (Option) ......................... 2
Remote Console (Option).................. 11
Replacement Parts
....See Form 740 or P-DVRDF/ADF
Rigging .................................................. 6
Roof Curb ............................................. 7
Pressure Null Switch (Option) .......... 14
Service...... See Form O-DV/RDF/ADF
Smoke Detector (Option) ................... 16
Technical Data ...................................... 3
Uncrating............................................... 3
Warranty ........................................... 3
®
C E R T I F I E D
Table of Contents
Paragraphs Pages
Installation ..................1-12 ..... 1-18
Check/Test/Start ............ 13 ... 19-24
ADDENDUM - Field-I stalled
Accessories ............................ 24-28

Page 2
This system is available with various air control options to meet a wide range
of application requirements. Depending on the air control option ordered, the
supply air volume may be varied or the outside air may be supplemented with
up to 75% building air (recirculation) for increased energy savings.
These systems are designed-certified to ANSI Standards by the Canadian Stan-
dards Association (CSA). (NOTE: Optional recirculation is available for U.S.
installations only; recirculation is not available for Canadian installations.)
In order to retain certification, the installer must adhere to the installation and
operation requirements in the instruction manual. These direct-fired makeup
air systems are not approved for residential use.
1. Installation Codes/Requirements
Installation should be done by a qualified agency in accordance with the in-
structions in this manual and in compliance with all codes and requirements of
authorities having jurisdiction. The qualified agency installing this system is
responsible for the installation.
These units must be installed in accordance with local building codes. In the
absence of local codes, the unit must be installed in accordance with the Na-
tional Fuel Gas Code ANSI Z223.1a (latest edition) or CAN/CGA B149, In-
stallation Codes for Gas Burning Appliances. These codes are available from
CSA Information Services, 1-800-463-6727.
Before installation, always consult authorities having local jurisdiction to verify
that local codes and procedures are being followed.
The building should always provide adequate relief for the heater to operate at
its rated capacity. It should be noted that this can be accomplished by taking
into 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 these methods. Excessive
recirculation or insufficient ventilation air which results in inadequate dilu-
tion of the combustion products generated by the heater may create haz-
ardous concentrations of carbon dioxide, carbon monoxide, nitrogen diox-
ide, and other combustion products into the heated space.
If the failure or malfunction of this heater creates a hazard to other fuel burn-
ing equipment in the building, interlock the system to open inlet dampers or
other such devices.
Recirculation Requirements - Do not install a system with optional recircula-
tion (building air) in the presence of flammable solids, liquids, or gases; explo-
sive materials (i.e., grain dust, coal dust, gun powder, etc.); or substances which
may become toxic when exposed to heat (i.e. refrigerants, aerosols, etc.). If a
system with recirculation is being installed in an area where propane fork trucks
or other fossil fuel powered equipment are used, the ventilation requirements
for that equipment must be met. Recirculation is not recommended in uninsu-
lated buildings where outside temperatures fall below 32°F (0°C).
If in doubt regarding an application, consult the heater manufacturer's repre-
sentative before installation.
Codes for Special Installations: (1) Aircraft Hangar -- Installation in an air-
craft hangar must be in accordance with the Standard for Aircraft Hangars,
ANSI/NFPA 409 (latest edition) or CAN/CGA B149 Installation Codes; (2)
Public Garage -- Installation in a public garage must be in accordance with the
Standard for Parking Structures, ANSI/NFPA 88A (latest edition) or the Stan-
dard for Repair Garages, ANSI/NFPA 88B (latest edition) or in Canada with
CAN/CGA B149 Installation Codes.
General
Description
(cont'd)

Form I-RDF, P/N 148384 (Rev 1), Page 3
Hazard Intensity
Levels Apply to
Warnings
throughout this
Manual
3. Technical Data
Immediately upon uncrating the unit, check the gas specifications and electri-
cal voltage (system rating plate is in the control compartment) to be sure that
they agree with the supply at the installation site. Check for any damage that
may have been incurred during shipment. If damage is found, document the
damage with the carrier and contact your distributor.
The following control parts are shipped loose inside the unit:
a 3-position control switch mounted in a 4x4 junction box (except units
with Option AG37) NOTE: If an optional remote console is ordered, this
switch is mounted on the console; the console is shipped separately.
Depending on the gas and/or air controls selected, the following additional
parts are shipped inside the unit or separately.
Gas Controls Shipped-Loose Parts
Options AG30, AG32, *Remote Temperature Selector
AG33, AG47, AG48
Option AG31 *Remote Temperature Selector,
Space Override Thermostat
Option AG36 Remote Console
Air Controls Shipped-Loose Parts
Option AR19, AR22 *Potentiometer
Option AR20, AR23 Remote Pressure 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 console is shipped separately.
On all sizes with an optional dirty filter switch, the tubing and clamps are
shipped inside the cabinet.
4. Uncrating/
Preparation
Model Sizes 1-20-3 1-40-3 1-50-3 1-65-3 2-80-3 2-120-3 3-180-3 3-260-3
MaximumCapacity (MBH) 400 600 750 750 1500 1500 2500 3000
CFM Range 1,000 - 2,000 - 3,000 - 4,000 - 6,000 - 9,000 - 11,000 - 16,000 -
3,000 4,500 6,000 6,500 12,000 16,000 20,000 28,000
MaximumTemperature Rise 120°F 120°F 120°F 120°F 120°F 120°F 120°F 120°F
MaximumDischarge Temperature 120°F 120°F 120°F 120°F 120°F 120°F 120°F 120°F
Typical Control Amps (24V) 8.0 8.0 8.0 8.0 8.0 8.0 8.0 8.0
Net Weight (lbs) 915 925 935 950 1455 1505 2410 2480
GasConnection(inches) 11111or1-1/41or1-1/41,1-1/4,or21,1-1/4,or2
HAZARDINTENSITYLEVELS
1. DANGER: Failure to comply will result in severe personal
injury or death and/or property damage.
2. WARNING: Failure to comply could result in severe personal
injury or death and/or property damage.
3. CAUTION: Failure to comply could result in minor personal
injury and/or property damage.
2. Warranty Refer to the limited warranty information on the warranty card included in the
"Owner's Envelope".

Page 4
6. Dimensions
System Dimensions
FIGURE 1 - Dimensions (inches and mm)
4. Uncrating/
Preparation
(cont'd)
Be sure that all shipped-separate accessories for the installation are available.
Other shipped-separate accessories could include a roof curb, a remote con-
sole, an outside air hood, a disconnect switch, and/or an indoor filter cabinet.
5. Clearances -
All Sizes
Clearance to combustibles is defined as the minimum distance from the heater
to a surface or object that is necessary to ensure that a surface temperature of
90°F above the surrounding ambient temperature is not exceeded. In order to
service the system, the minimum clearance on the control side of the unit must
be equal 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)
Y
B
(Cabinet
Height)
2-5/8 (67)
Control
Compartment*
Blower
Compartment
Supply Wiring**
24V Wiring**
E (Inside Width of Curb Cap)
X
U
W
TV
C (Cabinet Width)
1 (25)
Horizontal
Discharge
(T x U )
S
R
Outside Air
Opening
(R x S)
See Outside Air Hood or
Filter Cabinet Dimensions
on page 5.)
N
L
P
QM
G
K
J
F
H
Optional Return Air
Opening (F x G)
Bottom
Discharge
(L x M)
3 (76)
Gas Supply
(Y and )
* RDF-2 and RDF-3 systems have double hinged doors as illustrated. Control compartment on RDF-1 has a single hinged door.
** Configuration is for RDF-2 and RDF-3. The supply connection on the RDF-1 systems is above the control wiring connection.
Clearances - inches (mm)
Control Side O
pp
osite Bottom
Side O
pp
osite To Combustibles To Non-Combustibles
3 (76) Width ofunit 3 (76) 3 (76) 0 -Curb
Top

Form I-RDF, P/N 148384 (Rev 1), Page 5
Outside Air Hood
or Indoor Filter
Cabinet
FIGURE 2 - Optional
OutsideAirHoods and
Filter Cabinets with and
withoutFilters
A
B
C
G
H
D
E
F
1-1/4 (32)
19-1/2
(495)
3 (76)
OptionAS2, OutsideAir Hood
OptionAS6, OutsideAir Hood
with 1" Filters
OptionAS7, OutsideAir Hood
with 2" Filters
OptionAW3, IndoorFilter
Cabinet with 1" Filters
OptionAW6, IndoorFilter
Cabinet with 2" Filters
NOTE: Refer to Paragraph 15
for assembly and installation
instructions.
Dimensions
Size
inches mm inches mm inches mm
A38 965 62 1575 74-1/4 1886
B55 1397 54 1372 64 1626
C36 914 47-1/2 1207 61-3/8 1559
D35-9/16 903 59-9/16 1513 71-9/16 1818
E33-1/8 841 44-5/8 1133 58-1/2 1486
F19-1/2 495 19-1/2 495 19-1/2 495
G (Duct Connection) 32-15/16 837 56-15/16 1446 69-3/8 1762
H (Duct Connection) 30-3/8 772 41-7/8 1064 57-7/16 1459
1-20, 1-40, 1-50, 1-65 3-180, 3-2602-80, 2-120
Dimensions (inches)
Model Sizes A B C D E F G H J K L M
1-20-3, 1-40-3,
1-50-3, 1-65-3 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, 3-260-3 135-3/4 61-5/8 82-9/16 132-9/16 83-1/8 64-9/16 19-1/16 5-5/32 13-13/32 21-5/8 37 37-3/32
Model Sizes N P Q R S T U V W X Y Z
1-20-3, 1-40-3,
1-50-3, 1-65-3 7-11/16 14-5/8 12-5/8 31-1/8 31-1/8 21-3/4 18-3/4 7-3/4 5-1/4 13-1/8 8-9/16 42-7/32
2-80-3, 2-120-3 16-5/16 24-21/32 11-7/32 55-3/16 42-5/8 27-1/4 27-1/4 16-5/32 6-11/32 15-3/32 8-3/4 48-15/16
3-180-3, 3-260-3 14-9/16 31-9/16 7-7/16 67-1/8 55-9/16 36-3/4 36-3/4 14-7/16 4 20-7/8 8-11/16 56
Dimensions (mm)
Model Sizes A B C D E F G H J K L M
1-20-3, 1-40-3,
1-50-3, 1-65-3 2235 943 1122 2154 1156 622 267 138 363 397 556 486
2-80-3, 2-120-3 2235 1237 1734 2154 1765 1321 413 135 278 394 691 691
3-180-3, 3-260-3 3448 1565 2097 3367 2111 1640 484 131 341 549 940 942
Model Sizes N P Q R S T U V W X Y Z
1-20-3, 1-40-3,
1-50-3, 1-65-3 195 371 321 791 791 552 476 197 133 333 217 1072
2-80-3, 2-120-3 414 626 285 1402 1083 692 692 410 161 383 222 1243
3-180-3, 3-260-3 370 802 189 1705 1411 933 933 367 102 530 221 1422

Page 6
8. Location and
Mounting
7. Rigging All cabinets are furnished with a curb cap and four lifting lugs for attaching
rigging. To prevent damage to the cabinet, use spreader bars with the rigging
chains.
Mounting the system is the responsibility of the installer. Verify that the sup-
porting structure has sufficient load-carrying capacity to support the weight.
NOTE: Net weights are approximate for the standard system. Optional equip-
ment is not included.
Mounting on Field-
Supplied Supports
The system is equipped with a load-bearing curb cap which forms an integral
part of the unit. The curb cap provides required clearance from combustibles.
Whether the system is being mounted directly on a surface or being placed
"up" on additional structure, the horizontal length must be supported by two
4x4 treated wooden rails. Refer to FIGURE 3 for the appropriate lengths and
spacing. When the system is placed on the rails, the curb cap "skirt" must fit
over the edge of the boards with the rails setting inside the horizontal length of
the curb cap.
If the rails are laid directly on the mounting surface, position them as shown in
FIGURE 3. Set the system on the rails leaving the "ends" underneath open for
ventilation.
If the wooden rails are not 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-
ance from the bottom of the inlet air hood to the mounting surface.
Depending on the building and its use, determine whether or not additional
measures should be taken to reduce the effect of blower vibration and/or noise.
When selecting a location for an outdoor installation, position the unit so that
the air inlet will NOT be facing into the prevailing wind. A minimum of 14"
(356mm) clearance is required from the bottom of the air inlet hood to the
mounting surface.
Prior to installation, be sure that the method of support is in agreement with all
local building codes. For both indoor and outdoor installations, check for ser-
vice platform requirements. If an outdoor system is being installed with bot-
tom discharge and/or return air, a full perimeter roof curb is recommended.
FIGURE 3 - Placement of
MountingRails
A
B
4 x 4 Treated Lumber
Weights Net Wei
g
ht of Basic S
y
stem
Sizes 1-20 1-40 1-50 1-65 2-80 2-120 3-180 3-260
lbs 915 925 935 950 1455 1505 2410 2480
kg 415 420 424 431 670 683 1093 1125
Mounting Rail Placement
Model A (inches) B (inches)
1-20, 1-40, 1-50, 1-65 85-1/4 45-1/2
2-80, 2-120 85-1/4 69-7/16
3-180, 3-260, 122, 130 132-5/8 83-1/16
Model A(mm) B (mm)
1-20, 1-40, 1-50, 1-65 2165 1156
2-80, 2-120 2165 1764
3-180, 3-260 3369 2110

Form I-RDF, P/N 148384 (Rev 1), Page 7
FIGURE 4 - Cross Support
MountingRequirements
Field
Supplied
Duct
Field
Supplied
Duct
4 x 4 reated Lumber
= support location
FIGURE 5 - Dimensions
of Optional Roof Curb
(Option CJ3) - Shipped
Separately
CAUTION: Before installing curb, recheck to be sure that the
correct curb has been ordered. Be sure that the curb selected
matches the unit ordered. Verify the dimensions of the curb
received with the dimension table in FIGURE 5.
Mounting on a
Roof Curb
IMPORTANT NOTE:
Area enclosed by roof curb
must comply with clearance
to combustible materials. If
the roof is constructed of
combustible materials, area
within the roof curb must be
ventilated, left open, or
covered with non-combus-
tible material which has an
"R" value of at least 5. If
area within curb is left
open, higher radiated sound
levels may result.
B
A
C
D
1-7/8
(48)
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 Series 3
Whether the roof curb is Option CJ3 designed for the system or a field-sup-
plied curb, the roof curb dimensions in FIGURE 5 and the ductwork opening
dimensions in FIGURE 7 apply.
The roof curb designed for the system includes dividers that will create internal
ductwork and duct connection flanges for ease of installation and so that the
building ductwork can be attached before the system is set on the roof curb.
NOTE: Drawing is
not proportional for
all sizes.
Sizes inches mm inches mm inches mm
A84-5/8 2149 84-5/8 2149 131-3/4 3346
B43-5/8 1108 67-9/16 1716 82-1/16 2084
C80-7/8 2054 80-7/8 2054 128 3251
D39-7/8 1013 63-13/16 1621 78-5/16 1989
Height
Weight
RoofCurbDimensions (±1/8"or 3mm)andA
pp
roximate Wei
g
hts
171 lbs(78 kg) 224 lbs(102 kg) 307 lbs(139 kg)
1-20-3, 1-40-3,1-50-3,1-65-3 2-80-3,2-120-3 3-180-3,3-260-3
16 inches (406 mm)

Page 8
16
(406mm)
1-7/8(48mm)
4
(102mm)
2 x 6 Wood Nailer
1-1/2 x 3 lb
Fiberglass
Flashed by the
installer (flashing must
be under lip of curb)
Lag Screw
Cap
Screws
FIGURE 6 - Option CJ3
Roof Curb Cross Section
and Corner Detail
Corner
Detail
Curb
1. If installing an Option CJ3 curb, follow these instructions. If installing a
field-supplied curb, the curb must be level and must be sealed to the
system curb cap.
2. Position the roof curb end assemblies and side assemblies as shown in the
drawing in FIGURE 5, page 7. Fasten with bolts and lag screws as
illustrated in the corner detail (FIGURE 6).
8. Mounting
(cont'd)
3. If the system has a bottom discharge and/or a return air inlet, use the
sheetmetal screws to sub-assemble the dividers. Refer to the dimensions
in FIGURE 7 to appropriately position the roof curb dividers to create the
needed duct opening flanges. Attach the dividers to the roof curb with
sheetmetal screws. NOTE: If the system does not have a bottom discharge
and/or a return air opening, the dividers for an opening that is not going
to be used may be installed but are not required.
4. Check the assembly for squareness. The curb must be adjusted so that the
diagonal measurements are equal within a 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 required and secure curb to the roof
deck before installing flashing.
6. Install field-supplied flashing.
7. Before placing the RDF unit on the curb, apply furnished 1/4" x 1-1/4"
foam sealant tape to the top perimeter surface of the curb, making good
butt joints at corners. The sealant tape must be applied to the curb rails to
Mounting on a Roof
Curb (cont'd)
Components in Option CJ3
Roof Curb (Refer to
FIGURE 5 to identify the
Item)
Roof Curb
Installation
Instructions
Com
p
onents in Roof Curb O
p
tion CJ3
RoofCurbFrame and Internal DuctworkDividers (See FIGURE 5)
Item Qty Description
12 Curb Front and Back Assemblies
22 Curb Side Assemblies
34 Full Width Curb Dividers -- two (2) for bottom discharge supply
airduct o
p
enin
g
and two
(
2
)
for o
p
tional return air duct o
p
enin
g
42 Cross Dividers forBottomDischarge Supply AirOpening
52 Cross Dividers for Optional Return Air Opening
RoofCurbCorner Hardware
8 5/16"x 1"Lag Screws,P/N16243
8 5/16"Lockwasher, P/N1333
8 5/16"x 3/4"Hex Head Cap Screw,P/N16247
8 5/16"Lockwasher, P/N1333
8 5/16-18 Hex Nut, P/N1035
Hardware to Assemble and AttachDividers to make DuctworkOpenings
64
For Top
Two "Holes"
For Bottom
Two "Holes"
#10 Sheetmetal Screws, P/N11813

Form I-RDF, P/N 148384 (Rev 1), Page 9
Airflow
Assembled Dividers for Optional
Return Air Ductwork in the Roof Curb
Field-supplied ductwork may be either
dropped in from the top resting on
the top flange or be attached to the bottom
flange, using the dividers as ductwork.
Bottom
Discharge
Supply Air
Opening
(A x B)
Return
Air
Opening
(E x F)
A
C
BD
E
F
G
H
3/4 (19)
3/4 (19)
Top View
FIGURE 7 - Divider Locations for
Bottom Ductwork Openings
NOTES:
Drawing is not proportional for all
sizes.
3/4" (19mm) measurement is the
width of the flanges where the roof
curb mates with the heater. Flange
surface must be sealed.
When cutting duct openings in the
roof, cut opening(s) 1” (25mm)
larger than duct size opening for
installation clearance.
9. Distribution of
Makeup Air
Makeup air can be introduced to the building either through distribution ducts
or through controlled pressurization with little or no ductwork. Makeup air
should be introduced and maintained using the lowest possible air velocity.
With ductwork distribution, this is accomplished using a multiplicity of dis-
charge openings over the greatest centerline distance. When a makeup air
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 distribution ductwork.
Makeup air should enter at the highest point practical. By doing this, the fresh
air will entrain dust laden air at the ceiling and move it toward the point of
exhaust. Also, fresh air directed downward from the roof or ceiling will mix
with hot ceiling air resulting in improved distribution of heat in the building.
Sizes inches mm inches mm inches mm
A23-11/32 593 28-13/32 722 38 965 A
B20-1/8 511 28-11/32 720 38 965 B
C5 127 13-15/32 342 11-19/32 294 C
D10-1/4 260 7 178 4-5/8 17 D
E25-1/2 648 54-11/16 1389 66-3/4 1695 E
F11-1/2 292 17-23/32 432 20-1/16 510 F
G11-15/32 291 8 203 10-15/32 266 G
H11-1/32 280 11-3/32 282 17-1/4 438 H
Roof Curb Duct O
p
enin
g
Dimensions (±1/8"or 3mm)
1-20,1-40,1-50,1-65 2-80,2-120 3-180,3-260
prevent water leakage into the curb area due to blown rain and capillary
action.
Also place the foam sealant tape on the perimeter of the top surface of the
duct opening(s), being sure to make good butt joints at corners. If install-
ing ductwork from the top, it is recommended that tape be put on again
after the ductwork is "dropped in", sealing below and above the duct
flanges.

Page 10
Always introduce fresh makeup air so that it moves across the greatest dis-
tance within the room or building before reaching an exhauster.
Proper sizing of warm air ductwork is necessary to ensure a satisfactory heat-
ing installation. The recognized authority for such information is the Air Con-
ditioning Contractors Association, 1228 17th Street, N.W., Washington, DC
20036. A manual covering duct sizing in detail may be purchased directly
from them.
10. Electrical
Supply,
Connections,
and Controls
All electrical wiring and connections including electrical grounding must be in
accordance with the National Electric Code ANSI/NFPA No. 70 (latest edition)
or the Canadian Electrical Code Part 1-C.S.A. Standard C22.1. Check any
local ordinances or utility company requirements that apply.
Run a separate line voltage supply directly from the building electrical panel
to the disconnect switch for the system. All external wiring must be within
approved conduit and have a minimum temperature rise rating of 60°C. For
motor load amps, see Paragraph 12 or check the motor nameplate. System
FLA is on the rating plate.
Specific wiring diagrams and complete instructions are packed with each unit
and should be kept readily accessible in legible condition.
9. Distribution of
Makeup Air
(cont'd)
Sizing and
Installation of
Distribution
Ductwork
(See FIGURE 1, page 4,
for duct dimensions.)
Wire Gauge - 100 ft (30M) maximum
Full Load
Amps 5 10152025303540
Wire
Gauge 141412108866
Disconnect Switch A safety disconnect is required. Refer to FIGURE 8 for recommended loca-
tion and install the disconnect switch in accordance with Article 430 of the
National Electrical Code ANSI/NFPA 70 or in accordance with Canadian Elec-
oThe type of duct installation depends in part on the type of construction of
the roof (wood joist, steelbar joist, steel truss, pre-cast concrete, etc.) and
the ceiling (hung, flush, etc.).
oRectangular ducts should be constructed of not lighter than No. 26 U.S.
gauge galvanized iron or No. 24 B&S gauge aluminum.
oAll duct sections 24" or wider, and over 48" in length, should be cross-
broken on top and bottom and have seams or angle-iron braces. Joints
should be S and drive strip or locked.
oWarm air ducts should not contact masonry walls. Insulate around all air
ducts through masonry walls with not less than 1/2" of insulation.
oInsulate all exposed warm air ducts passing through an unheated space
with at least 1/2" thickness of insulation.
oDuct Supports - Suspend all ducts securely from adjacent building
members. Do not support ducts from unit duct connections.
oDuct Connections - At the heater, use a flexible canvas connection on
indoor units to eliminate vibration transmission.
On outdoor roof curb, down discharge connections, either drop an appro-
priate sized and flanged duct into the roof curb prior to setting the unit or
attach ductwork to the bottom flange (using curb dividers as ductwork). If
dropping ductwork from the top, it is recommended that the top perimeter
be sealed above and below the added ductwork. Do not use screws. See
ductwork connection locations and sizing, pages 7 and 9.
On outdoor horizontal installations, the ducts can be slid over the flange
of the heater and then sealed for an airtight and watertight fit. On horizon-
tal duct-to-heater connections and connections to the flanges at the
bottom of the curb, use sheetmetal screws to fasten ducts to the heater
flange. Use stiffening flanges around the perimeter of all duct connec-
tions.
oReturn Air Duct - The return air duct must be sized for a pressure drop
of .5" w.c. at 2440 fpm in order to balance the system. If not sized
properly, there may be difficulty in obtaining the desired airflow over the
burner when the return air damper is full open.

Form I-RDF, P/N 148384 (Rev 1), Page 11
Control Side
Control
Compartment*
Blower
Compartment
Supply Wiring**
24V Wiring**
Gas Supply
CAUTION: If any of the
original wire must be
replaced, the replace-
ment wire must have a
temperature rating of at
least 105°C except for
controls mounted in the
discharge airstream
which must be 150°C.
See Hazard Levels, page
2.
trical Code Part 1-C.S.A. Standard C22.1. When attaching the disconnect switch
to the heater, use hardware with "teeth" to provide electrical grounding. The
"teeth" should face the disconnect switch, scratching off the painted surface.
Attach the disconnect tightly against the heater cabinet. Run cable so that it
does not interfere with cabinet panels or doors.
When providing or replacing fuses in a fusible disconnect switch, use dual
element time delay fuses and size according to 1.25 times the maximum total
input amps.
Convenience Outlet Option
When a convenience outlet option is included, an individual power supply
must be provided to the receptacle. This circuit MUST BE on a ground fault
breaker to meet requirements. All wiring to the convenience outlet must meet
National Electrical Code ANSI/NFPA No. 70 (latest edition) or the Canadian
Electrical Code Part 1-C.S.A. Standard C22.1. and any local or utility codes
that may apply.
Control Wiring Maximum Lengths (ft)
Volts Wire
Gauge Total Wire
Length Distance from Unit to Control
24 18 150 75
24 16 250 125
24 14 350 175
Control Wiring Maximum Lengths (M)
Volts Wire
Gauge Total Wire
Length Distance from Unit to Control
24 18 45.7 22.9
24 16 76.2 38.1
24 14 106.7 53.3
FIGURE 8 - Location of Gas Connec-
tion, Electrical Supply Connection, and
Control Wiring Connections on RDF
Series3 Direct-FiredSystems
FIGURE 9 - Option RC14 with Dirty
FilterLight andPotentiometer 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 ordered, the console could
include a temperature selector and/or a potentiometer. If a dirty
filter switch is ordered the indicator light is on the console. See
FIGURE 10 for console size.
NOTES:
*RDF-2 and RDF-3 Series 3 systems have double hinged doors as
illustrated. Control compartment on RDF-1 Series 3 systems has a
single hinged door.
** Configuration shown is for RDF-2 and RDF-3 Series 3. The
supply connection on the RDF-1 Series 3 systems is above the
control wiring connection.
Disconnect
Switch
Location
Control Wiring A 7/8" diameter opening suitable for watertight conduit connection is pro-
vided as the entrance of 24-volt control wiring to the electrical compartment.
For location, see FIGURE 8. Low voltage wiring must be in individual con-
duit, separated from primary high voltage wiring.
CAUTION: Supply voltage and 24-volt control wiring cannot be
installed in the same conduit. Maxitrol systems will be adversely
affectedif controlwiring is inconduit with supplyvoltage wiring.
If required, field-supplied wiring between any Maxitrol
components must be completed with shielded wiring.
A 3-position control switch mounted in a 4x4 box is supplied with each system
(exception - not included with systems with Option AG37 designed for com-
puter control), either packed loose inside the unit, or if an optional control
console (Option RC13 or RC14; See FIGURE 9) is ordered, the switch is
mounted on the console.
Control wiring requirements depend on the options selected. Follow the cus-
tom wiring diagram supplied with the system to connect any remote controls.
In this paragraph, there is a brief description of the optional electrical controls
used for airflow. Refer to the operation manual, Form O-DV/RDF/ADF, for
additional control information.

Page 12
FIGURE 11 - Dirty Filter
Pressure Switch Set screw (on
front of switch)
must be
manually
adjustedafter
systemis in
operation.
Negative pressure connection is
toward the "back or bottom"
of the switch (senses blower side
offilters)
Positivepressure connectionis
toward the "front or top" of the
switch(senses air inlet side of filters)
FIGURE 10 - Remote Console Dimensions
Dirty Filter Light
2-3/8
(60)
6 (152)
5-15/32 (139)
1-5/16 (33)
1-3/32 (28)
4-7/16
(113)
1-3/32 (28)
FIGURE 10 - Technical Data ofthe Remote Console (Variationsdependon options selected;consultcustom wiring diagram for
controls andto determine wirin
g
re
q
uired.)
Control Qty of Temperature Potentiometer Dimensions - inches (mm)
Switch Lights* Selector** *** L**** H**** D
Yes 3 Yes No 10-3/4 (273) 7-5/8 (194) 2-5/8 (67)
Yes 3 No No 10-3/4 (273) 7-5/8 (194) 2-5/8 (67)
Yes 3 Yes Yes 15-3/4 (400) 7-5/8 (194) 2-5/8 (67)
Yes 3 No Yes 10-3/4 (273) 7-5/8 (194) 2-5/8 (67)
Yes 4 Yes No 15-3/4 (400) 7-5/8 (194) 2-5/8 (67)
Yes 4 No Yes 15-3/4 (400) 7-5/8 (194) 2-5/8 (67)
Yes 4 Yes Yes 15-3/4 (400) 7-5/8 (194) 2-5/8 (67)
Yes 4 No No 15-3/4 (400) 7-5/8 (194) 2-5/8 (67)
* 3 - Blower On, Burner On, and Safety Lockouton both RC13 and RC14;
4th light is Dirty Filter Indicator on Option RC14 only
** On the console with Gas Control Options AG 31, 32, 33, 35, 47, or 48
*** On theconsole with Air Control Options AR19 or AR22
**** Subtract 1" (25mm) when recessing
Locations of Knockout
Holes(dimensions to
centerlines)
When a console with a dirty filter indicator is selected, the remote console
includes a fourth light (dirty filter indicator light). The light is activated by an
adjustable, single-pole/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 indicator light.
10. Electrical Supply, Connections and Controls (cont'd)
DirtyFilter Light
InstallationInstructions
oBefore the system is operating, connect the sensing tubes from the
switch to their sensing locations in the field-installed filter cabinet. (Cabi-
net installation instructions are in Paragraph 15.)
1) Run the tubes through the holes in the cabinet wall. Pull gently to
extend the tubing to its entire length without stress.
2) Position the tubing approximately at the center of the height of the filter
rack.
3) Identify the tube connected to the positive connection on the switch
(FIGURE 11) as the positive pressure tube. Determine the length of
tubing required to attach the positive pressure tube so that it will sense
pressure at the inlet side of the filter rack.
Identify the tube connected to the negative connection on the switch (FIG-
URE 11) as the negative pressure tube. Determine the length of tubing
required to attach the negative pressure tube so that it will sense the
pressure at the blower side of the filter rack.
(NOTE: Tubing shipped is the same length for all sizes of systems; cut to
the appropriate length for the smaller systems.)
4) If required, cut the tubing to the proper lengths. Using the clamps
provided, attach the ends of the tubing to the filter rack at about center
height being careful not to kink or compress the tubing.
oAfter the system is operating, the filter switch must be manually set.
With clean filters in place, blower doors closed, and blower in operation,
increase the pressure setting by adjusting the set screw on the switch

Form I-RDF, P/N 148384 (Rev 1), Page 13
clockwise until the filter light is energized or the screw is bottomed out. At
that point, adjust the set screw three full turns counterclockwise or until
the screw is top ended. At that setpoint, the filter light will be activated at
approximately 50% filter blockage.
Discharge Sensor (Maxitrol) for Gas Control Options
AG30, AG31, AG32, AG33, AG47, AG48
A discharge sensor may be shipped separately for field installation. Attach the
discharge sensor and mixing tube in the ductwork about six feet (1.8 M) from
the discharge opening of the system.
The sensor housing is not waterproof. If the installation is outdoors, field-fab-
ricate a waterproof protective enclosure for the discharge sensor, being careful
not to affect its air temperature sensing capability. If the ductwork is insulated,
be sure that the sensing bulb is mounted so that it is fully exposed to the air-
stream being sensed.
Refer to the wiring diagram and connect the sensor to the terminal strip in the
blower section electrical box. Use shielded wire to alleviate any electrical in-
terference that may cause an erroneous discharge temperature reading.
Outside Air Cutoff Control (Option BN2)
After sensing pilot flame, the burner ignites at its lowest input rate. The "amount
of heat" required to reach the desired discharge temperature also depends on
the temperature of the incoming outside air. The outside air cutoff (high ambi-
ent control) is factory set at 60°F (adjustable 25-250°F). The burner reacts
differently depending on the entering air temperature and the setting on this
control. The burner --
• may not ignite (pilot 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 completely only on Option BN2 control, once burner has
been fired; or
Modulating operation will depend on the temperature rise between the
outside air and the discharge air setting.
• may remain on continuous low fire.
If the outside air control is set too high, the burner will continuously burn
on low fire as long as the control switch is set to "winter".
When the outside air control is set properly for the climate, the system blower
will continue to provide the required makeup air (ventilation) at the ambient
outdoor temperature (burner not operating) even when the control switch is set
to "winter".
If at startup, it is determined that the outside air cutoff control is not set prop-
erly, change the setting on the control (located in the main electrical compart-
ment) and test for proper operation.
Discharge Temperature Low Limit (Option BE2)
If the system has an optional low limit switch for discharge temperature
(freezestat), the control is in the blower section electrical box. The sensing
bulb must be field-mounted in the blower discharge duct connector. Uncoil the
control and extend the bulb to the blower discharge, being careful to not inter-
fere with any mechanical parts. Use the bulb holder provided and mount the
sensor according to the manufacturer's instructions.
Door Switch (Option BX1)
If the system is to be used as an overhead door heater, an optional door switch
(Option BX1) must be installed. The function of the switch is to energize and
FIGURE 12 - Discharge
Sensor and Mixing Tube
FIGURE 13 - Control used
for Outside Air Cutoff and
Discharge Temperature
LowLimit (Freezestat)
FIGURE 14
-Optional
Door Switch

Page 14
10. Electrical
Controls
(cont'd)
interlock the system when an outside overhead door reaches approximately
80% of full open travel. The switch will de-energize the system when the over-
head door closes approximately 20%. Follow the installation instructions in
the door switch option package and the wiring diagram.
Firestat (Option BD5)
If the system has an optional firestat, the control is factory installed in the
heated airstream so that the sensor extends into the duct. This control requires
manual reset so is installed in an accessible location.
Optional Potentiometer (applies to systems with Air
Control Option AR19 for makeup air only or AR22
for outside and recirculation air)
If the system includes Air Control Option AR19, the discharge damper is con-
trolled by a manually set potentiometer. If the system includes Air Control
Option AR22, the potentiometer controls the return air damper. The potenti-
ometer is shipped loose in the control compartment, or if a remote console is
ordered, it is mounted on the console.
Follow the wiring diagram to connect the potentiometer.
Optional Pressure Null Switch (applies to systems
with Air Control Option AR20 for makeup air only or
AR23 for outside and recirculation air)
If the system includes Air Control Option AR20, the discharge damper is con-
trolled by a pressure null switch. If the system includes Air Control Option
AR23, the pressure null switch controls the return air damper. The pressure
null switch is shipped in the control cabinet. Refer to the following paragraphs
and to the manufacturer's installation instructions to install and connect 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 control building pressure. It maintains a selected
positive or negative pressure setpoint by changing the amount of outside air
being introduced to the building through the modulating outside air dampers.
As more pressure is required in the building, the pressure null switch activates
the damper motor driving the outside air damper towards the full open posi-
tion and the recirculated air damper towards the closed position. Conversely,
as less pressure is required, the switch drives the dampers in the opposite di-
rection.
FIGURE 15
-Optional
Firestat
FIGURE 16 -
Optional
Potentiometer
FIGURE 17 - Pressure
Null Switch
InstallationInstructionsfor
Pressure Null Switch (See
FIGURE 18):
Select an indoor location free from excessive vibration where oil or water will
not drip on the switch and where ambient temperature will be within a range of
-30°F (dry air) to 110°F.
Mount the switch with the diaphragm in a vertical plane. The switch is position
sensitive and is calibrated to operate properly when the diaphragm is vertical.
Mount switch securely.
Connect the pressure taps on the top of the switch to sources of air pressure
differential. Metal tubing with 1/4" O.D. is recommended but any tubing which
will not unduly restrict the airflow can be used. To maintain a positive building
pressure, vent the low pressure tap to the outdoors and allow the high pressure
tap to monitor building pressure. To maintain a negative building pressure,
reverse the functions of the high and low pressure taps. In either case, be sure
that the outdoor vent is protected from the wind and screened from insects.
Door Switch (cont'd)

Form I-RDF, P/N 148384 (Rev 1), Page 15
Increasing
Decreasing Linkage to
Diaphragm
Low
Common
High
Span Adjustment
Span of
floating
contact
Switching action in the pressure null switch
Electric Box
Span
Adjust
Screw
Mounting Plate
Pressure Taps
Low
High
Pressure
Adjust
Screw
FIGURE 18 - Pressure Null
Switch included inAir
Control OptionsAR20 and
AR23
Optional Photohelic Pressure Switch (applies to
systems with Air Control Option AR36 for makeup
air only or AR37 for outside and recirculation air)
If the system includes Air Control Option AR36, the discharge damper is con-
trolled by a photohelic pressure switch. If the system includes Air Control
Option AR37, the photohelic pressure switch controls the return air damper.
The photohelic pressure switch is shipped separately.
The photohelic switch uses relays to control between high and low pressure
setpoints. When the pressure changes, reaching either setpoint, the beam from
an LED to the limiting phototransistor will be cut off by the helix-driven light
shield. The resulting signal change is electronically amplified to actuate its
DPDT slave relay and switching occurs. Pressure rating is 0" w.c. to .25" w.c.
Mount the switch with the scale vertical in a location where the ambient tem-
perature is between 20° and 120°F. Pneumatic pressure sensing lines may be
run any distance. Refer to the manufacturer's installation instructions and the
wiring diagram to install and connect this switch.
Optional Field-Provided Computer Control (applies
to systems with Air Control Option 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 system
includes Air Control Option AR34, the computer controls the return air damper.
With AG37, the gas valve and burner modulation are controlled by the field-
supplied computer signal. With AG51, the gas valve and burner modulation
and outside air damper are controlled by the field-supplied computer signal.
Follow the signal conditioner manufacturer's instructions included with the
system for connecting to the field-provided control.
FIGURE 19 - Photohelic
Pressure Switch
IMPORTANT: To eliminate shipping damage to the
switch contacts, the manufacturer reduced the span
adjustment to zero before shipping. The span should be
adjusted prior to using the switch. (If the switch has been
installed, disconnect the vent tube so that the null switch
is in a neutral position.) Remove the switch electrical box
cover and while observing the contacts, turn the span
adjustment screw slowly in a clockwise direction. Con-
tinue turning the adjustment screw until you are able to
see gaps between the common and both the low and high
contacts. A minimum gap provides the greatest sensitiv-
ity. The wider the gap, the lower the sensitivity.
Adjustment of the Switch - The "high" actuation point of the null switch is
indicated on a calibrated scale secured to the transparent range screw enclo-
sure. Building pressure is set by turning the adjustment screw. The "low" ac-
tuation point is set by adjusting the span on the null by turning the span adjust-
ment screw. The span range is .01 to .03" w.c.
FIGURE 20 - Maxitrol
A200 Signal Conditioner,
P/N 134170

Page 16
Gas
Supply
Piping
Capacity of Piping
Cubic Feet perHour based on 0.3" w.c. Pressure Drop
Specific Gravity for Natural Gas -- 0.6 (Natural Gas -- 1000 BTU/Cubic Ft)
Specific Gravity for Propane Gas -- 1.6 (Propane Gas -- 2550 BTU/Cubic Ft)
Length DiameterofPipe
of 1" 1-1/4" 1-1/2" 2" 2-1/2" 3" 4"
Pipe Natural Propane Natural Propane Natural Propane Natural Propane Natural Propane Natural Propane Natural Propane
20’ 350 214 730 445 1100 671 2100 1281 3300 2013 5900 3599 12000 7320
30’ 285 174 590 360 890 543 1650 1007 2700 1647 4700 2867 9700 5917
40’ 245 149 500 305 760 464 1450 885 2300 1403 4100 2501 8300 5063
50’ 215 131 440 268 670 409 1270 775 2000 1220 3600 2196 7400 4514
60’ 195 119 400 244 610 372 1105 674 1850 1129 3250 1983 6800 4148
70’ 180 110 370 226 560 342 1050 641 1700 1037 3000 1830 6200 3782
80’ 170 104 350 214 530 323 990 604 1600 976 2800 1708 5800 3538
90’ 160 98 320 195 490 299 930 567 1500 915 2600 1586 5400 3294
100’ 150 92 305 186 460 281 870 531 1400 854 2500 1525 5100 3111
125’ 130 79 275 168 410 250 780 476 1250 763 2200 1342 4500 2745
150’ 120 73 250 153 380 232 710 433 1130 689 2000 1220 4100 2501
175’ 110 67 225 137 350 214 650 397 1050 641 1850 1129 3800 2318
200’ 100 61 210 128 320 195 610 372 980 598 1700 1037 3500 2135
Note: When sizing supply lines, consider possibilities of future expansion and increased
requirements.Referto NationalFuelGas Code foradditionalinformation on line sizing.
FIGURE 21 - Duct Smoke
Detector (cover removed)
All piping must be in accordance 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. Read this section of the installation manual to determine the minimum
gas supply pressure required to provide a maximum gas capacity. Minimum
gas supply pressure is also stated on the heater rating plate. The heater mani-
fold terminates at the gas supply connection with a black iron pipe union. See
FIGURE 22. Local codes may require a 6" condensate trap. Gas connection is
either 1", 1-1/4", or 2" depending on the size of the system.
11. Gas Piping
and
Pressures
Optional Photoelectric Duct Smoke Detector
If the system has an optional photoelectric air duct smoke detector, the control
is shipped separately for field installation. The sensor must be field-mounted
in the discharge duct and electrically connected in the blower section electrical
box.
Follow the manufacturer's instructions and the wiring diagram for mounting
and connecting the control.
WARNING:High
pressure testing of
supply lines is
acceptable, provided the
supply line has been
disconnected from the
unit and the pipe end is
capped. See Hazard
Levels, page 2.
From Gas
Supply
From
Gas
Supply
6 Drip Leg
NOTE: Connections
shown are by the installer.
To Burner
and Controls
Manual
Gas Valve
A manual shutoff valve and an adapter with a 1/8"
NPT plugged hole for test gauge connection must
be installed immediately upstream of the gas
supply connection to the appliance.
Ground
Joint
Union
1/8
NPT
NOTE: To permit
burner removal this
nipple must extend
beyond the edge
of the heater.
FIGURE 22 - Gas Supply
Connection
10. Electrical Controls (cont'd)

Form I-RDF, P/N 148384 (Rev 1), Page 17
These direct-fired makeup air systems are designed to operate on a natural gas
supply differential pressure range of a minimum of 4.3-5.0" w.c. plus the mani-
fold pressure drop. Maximum supply pressure depends on specific unit firing
rate and manifold selection; see below. If the natural gas supply pressure is
above the maximum allowed, it is necessary to install a field-supplied step-
down gas regulator in the supply line. Order and install the appropriate Gas
Regulator Kit, Option CZ1 (1") or CZ2 (1-1/2"). These kits include spring-
loaded, lockup type regulators that comply with national and local codes speci-
fying that type of regulator. Follow the instructions provided with the kit. Mea-
sure the gas pressure between the step-down regulator and the unit.
Maximum Supply Pressure by Manifold
Manifold Option BM75, BM76, BM77 - 1/2 psi
Manifold Option BM78, BM79 - 2 psi
Manifold Option BM80, BM81 - 5 psi
Supply Pressure
Requirement by
Manifold Option
WARNING:All
components of the gas
supply system must be
leak tested prior to
placingequipmentin
service.NEVERTEST
FORLEAKSWITHAN
OPENFLAME.
Pilot Supply
Pressure
These systems are designed to operate 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 the gas pressure as measured at the burner
pressure tap. Measure manifold gas pressure with the blowers operating. Mini-
mum gas pressure at the burner is typically 4.3" w.c. for natural gas or typi-
cally 1.5" w.c. for propane gas.
FIGURE 23 - Pressure Tap
Locationsfor Measuring
Manifold and Pilot Pressure
Manifold Pressure
Minimum Supply Gas Pressure ("w.c.) for Full Fire
Manifold O
p
tion
with Gas Control
O
p
tion
Manifold Size
MBH Nat Pro Nat Pro Nat Pro Nat Pro Nat Pro Nat Pro Nat Pro Nat Pro
250 4.0 1.4 4.0 N/A 4.1 1.6 4.3 1.5 4.4 1.6 4.6 1.6 4.5 1.6 5.1 1.8
500 5.3 1.9 5.0 N/A 5.8 2.3 6.2 2.2 6.0 2.3 5.2 1.9 5.0 1.7 5.3 1.9
750 7.5 2.7 6.8 N/A 8.5 3.3 9.5 3.3 8.4 3.3 6.1 2.3 5.7 2.0 5.5 1.9
1000 12.4 4.7 11.7 4.6 7.4 2.8 6.7 2.4 5.8 2.1
1250 9.1 3.5 8.0 2.9 6.2 2.2
1500 11.2 4.3 9.6 3.5 6.6 2.4
1750 13.6 5.3 11.5 4.2 7.2 2.6
2000 16.5 6.3 13.7 5.0 7.8 2.8
2500 23.3 8.9 18.9 7.0 9.4 3.4
3000 11.3 4.1
BM80 BM81BM79
AG 30, 31,32, 33,35,36,37,47,48,or 51
1-1/4" 2" 1" 1" 1" 1"
AG1
BM75
1" 1-1/4"
AG3 AG 30, 31, 32, 33,
36,37,47,48,or 51
BM76 BM78
AG50
BM77
Inlet Pressure ap
Valve Valve Regulator Manifold Pressure ap
Gas
Supply
Pilot
Regulator Pilot Solenoid Valve
Pilot Pressure ap

Page 18
3 Cap
Screws
FIGURE 25 - Split Taper
Bushing
2Push-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)

Form I-RDF, P/N 148384 (Rev 1), Page 19
CAUTION:Thischart
lists full load amp
requirement of standard
motor and standard
controls. Optional
controls will increase
amprequirement.Add
motor amps and control
amps for approximate
unit full load amps.
System FLA are shown
on the rating plate.
Blower Motor Full Load Amps (open motors)
Motor HP 115V/1 230V/1 208V/3 230V/3 460V/3 575V/3
1/2 9.8 4.9 2.2 2.0 1.0 N/A
3/4 13.8 6.9 3.1 2.8 1.4 N/A
1 16.0 8.0 4.1 3.6 1.8 1.4
1.5 N/A 10.0 5.75 5.2 2.6 2.0
2N/AN/A7.56.83.42.4
3 N/A N/A 10.6 9.6 4.8 3.6
5 N/A N/A 16.8 15.2 7.6 5.4
7.5 N/A N/A 21.0 19.0 9.5 8.4
10 N/A N/A 29.0 25.2 12.6 10.4
15 N/A N/A 42.0 40.0 20.0 16.0
20 N/A N/A 53.0 50.0 25.0 20.0
25 N/A N/A 66.0 63.0 31.5 26.0
30 N/A N/A 78.0 74.0 37.0 28.5
13. Check-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 (Follow Steps in Sequence)
IMPORTANT NOTE: These instructions are designed for systems manufactured beginning 8/2003 equipped
with hot surface ignition and standard diagnostic lights. If the system being started was manufactured prior to
8/2003, contact your representative or the factory service department for appropriate startup procedures.
Control
Relays
Outside Air Cutoff
(high ambient limit control)
ime Delay
Relay 24-volt erminals
Ignition
Module
Maxitrol Amplifier
or Signal Conditioner Service
Switches
Status Lights
Circuit
Board
24-Volt erminals
Bypass
Damper
Motor
Return
Air
Damper
Motor
Motor
Starter
ransformer
Line Voltage
erminals
Starter
Relay
Relay for
Optional 2-Speed
High Low
Standard Pressure
Switches
Optional Dirty Filter
Pressure Switch

Page 20
Startup
13. Check-Test
Start (cont'd)
KEY to Check/Test/
StartupProcedures:
o Procedure applies to
allunits.
¡Procedure only applies
to units with the
optionalcomponent
referred to in that
procedure.
o1. Check to be sure that all field-installed accessories are installed.
o2. Check all field-installed wiring.
o3. Check all ductwork for obstructions; open all diffusers.
o4. Turn the three-position switch or optional summer/off/winter remote
console switch to OFF position. To prevent someone from turning the
system on, tape the switch leaving a note that it should be left in the OFF
position.
¡5. If the system includes an air control with a remote potentiometer, set
the position as follows::
Option AR19 (Variable Air Volume) - Turn full "open"
Option AR22 (Return Air) - Turn full "closed"
6. Check disconnect switch --
oTurn disconnect switch OFF.
oCheck disconnect switch to be sure that it is tightly secured against the
cabinet.
oIf disconnect is fusible, check that fuses are installed. If fuses are not
installed, insert dual element time delay fuses sized 1.25 times the maxi-
mum total input amps. Verify continuity of fuses.
7. Open the hinged gas/electric control compartment door --
oClose all manual gas valves.
oCheck all wiring and wiring connections on gas controls and electrical
components.
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 burner cutoff air control
(60°F).
8. Open the hinged door to the blower compartment --
oRemove any blocking and shipping supports.
oCheck that the blower belts are installed and have correct tension and that
pulleys are in alignment and locked to the shaft (See Paragraph 12).
Inside the compartment, remove the cover from the limit switch junction
box.
oReset manual limit switch.
oCheck wiring connections to limit switches, discharge air sensor, and
motor.
oReplace the junction box cover.
9. Turn ON gas supply valve and inlet manual shutoff valve on the mani-
fold.
oLeak test gas connections upstream of the electric gas valve. Be sure all
connections are tight and leak tested. WARNING: DO NOT TEST WITH
OPEN FLAME.
oTurn OFF manual gas valves.
10. Turn blower service switch (Electrical Compartment, See FIGURE 26)
to OFF position. If present, verify that damper test switch is in TEST
position.
1. Prepare system for startup testing --
oAttach a slope gauge (0 to 1.0" scale) to the tubing connections in the
control compartment. The two connections are located just left of the
electrical box. Remove the caps on the 1/8" NPT test connections and
attach the slope gauge. (The recommended method for attaching the slope
gauge is to use field-supplied 1/8" female NPT x 1/4" OD barbed hose
connections.)
Before Startup