Reznor RDF Series User manual

Page 1
INDOOR OR OUTDOOR, GAS,
DIRECT-FIRED, MAKEUP
AIR/HEATING SYSTEMS
(Specifications subject to change without notice.)
Installation Form RZ-NA 440 (Version B)
Obsoletes Form RZ-NA 440 (Version A)
WARNING: On makeu air heaters which also
recirculate room air, outside ventilation air must
be rovided in accordance with the information
shown on the heater name late.
Recirculation of room air may be hazardous in the
resence of:
(a) Flammable solids, liquids, and gases;
(b) Ex losive materials; or
(c) Substances which may become toxic when
ex osed to heat.
General Description
The information in this manual applies to Reznor® Model RDF
direct-fired makeup air heating systems. These systems consist
of a direct-fired, natural gas-fueled burner and a draw-through
blower housed in a weatherized cabinet. The systems may be
installed either indoors or outdoors.
This direct-fired makeup air system pro ides tempered makeup
air. Makeup air is defined as air that enters a building or area due
to negati e pressure created by an air exhaust load in excess of
the olume of entering air. This system warms the outside air
and monitors the olume and temperature of the makeup air added
to the building. The system may be used to pro ide entilation
in whole building or in spot applications. In whole building ap-
FOR YOUR SAFETY
WARNING: The use and storage of gasoline or
other flammable va ors and liquids in the vicinity
of this a liance is hazardous.
If you smell gas:
1. O en windows.
2. Don't touch electrical switches.
3. Extinguish any o en flame.
4. Immediately call your gas su lier.
WARNING: Im ro er installation, adjustment,
alteration, service, or maintenance can cause
ro erty damage, injury or death. Read the
installation, o eration, and maintenance
instructions thoroughly before installing or
servicing this equi ment.
WARNING: Gas-fired a liances are not designed
for use in hazardous atmos heres containing
flammable va ors or combustible dust, or
atmos heres containing chlorinated or
halogenated hydrocarbons. See Hazard Levels,
age 2.
A lies to: Reznor® Model Series RDF
Table of Contents Paragra hs Pages
Installation ............................................ 1-13 ....................... 1-11
Check/Test/Start ................................... 14 .......................... 12-17
Field-Installed Accessories ................... 15 .......................... 18-22
Index y Page Page
Makeup Air ....................................... 7
Motor Loads ................................. 11
Mounting ......................................... 6
Recirculation .................................... 2
Remote Console .............................. 7
Rigging ........................................... 6
Pressure Null Switch ....................... 9
Technical Data ................................. 3
Uncrating ......................................... 6
Warranty ......................................... 2
Index y Page Page
Belt Tension ................................... 11
Blower Rotation ............................ 11
Blower Speed Adjustment ............. 11
Clearances ....................................... 6
Installation Codes ........................... 2
Control Wiring ................................. 7
Con enience Outlet Option ............ 7
Optional Roof Curb .......................... 5
General Description ......................... 2
Dimensions ...................................... 3
Dirty Filter Switch ............................. 8
Index y Page Page
Disconnect Switch ........................... 7
Sizing and Installation of
Distribution Ductwork .................. 7
Electrical Supply and Connections .. 7
Optional Filter Cabinets ............ 4, 18
Gas Piping and Pressures............... 10
Gas Piping for Optional Vent
Val e ............................................ 10
HAZARD INTENSITY LEVELS ....... 2
Optional Outside Air Hoods ...... 4, 18
Reference: Operating/Maintenance/Service Manual, Form RZ-NA 440-OMS
Replacement Parts Manual, Form RZ-NA 740
MFG P/N 148384,
NOTE: Obsolete Form R M 440-9 included installation, operation, and maintenance information. Form 440 (Version B) includes only installation
information. For operation and maintenance information, refer to Form 440-OMS (Version A).

Page 2
plications, adding controlled makeup air will cause less infiltra-
tion of dust and dirt; will eliminate continuous backdraft in chim-
neys and ents; and will reduce space heating fuel costs.
This system is a ailable with arious air control options to meet
a wide range of application requirements. Depending on the air
control option ordered, the supply air olume may be aried or
the outside air may be supplemented with up to 75% building air
(recirculation) for increased energy sa ings.
These systems are designed-certified to ANSI Standards by the
Canadian Standards Association. In order to retain certification,
the installer must adhere to the installation and operation re-
quirements in the instruction manual. These direct-fired makeup
air systems are not appro ed for residential use.
1. Installation Codes/
Requirements
Installation should be done by a qualified agency in accordance
with the instructions in this manual and in compliance with all
codes and requirements of authorities ha ing 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 National Fuel Gas Code ANSI Z223.1a
(latest edition). This code is a ailable from CSA Information Ser-
ices, 1-800-463-6727.
Before installation, always consult authorities ha ing local ju-
risdiction to erify that local codes and procedures are being
followed.
The building should always pro ide 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 engi-
neering methods, the structure's designed infiltration rate; by
pro iding properly sized relief openings; by interlocking a pow-
ered exhaust system; or by a combination of these methods.
Excessive recirculation or insufficient ventilation air which
results in inadequate dilution of the com ustion products gen-
erated y the heater may create hazardous concentrations of
car on dioxide, car on monoxide, nitrogen dioxide, and other
com ustion products into the heated space.
If the failure or malfunction of this heater creates a hazard to
other fuel burning equipment in the building, interlock the sys-
tem to open inlet dampers or other such de ices.
Recirculation Requirements - Do not install a system with op-
tional recirculation (building air) in the presence of flammable
solids, liquids, or gases; explosi e 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 sys-
tem with recirculation is being installed in an area where propane
fork trucks or other fossil fuel powered equipment are used, the
entilation requirements for that equipment must be met. Recir-
culation is not recommended in uninsulated buildings where
outside temperatures fall below 32°F (0°C).
If in doubt regarding an application, consult the heater
manufacturer's representati e before installation.
Codes for Special Installations: (1) Aircraft Hangar -- Installa-
tion in an aircraft hangar must be in accordance with the Stan-
dard for Aircraft Hangars, ANSI/NFPA 409 (latest edition); (2)
Public Garage -- Installation in a public garage must be in accor-
dance with the Standard for Parking Structures, ANSI/NFPA 88A
(latest edition) or the Standard for Repair Garages, ANSI/NFPA
88B (latest edition).
HAZARD INTENSITY LEVELS
1. DANGER: Failure to com ly will result in severe
ersonal injury or death and/or ro erty damage.
2. WARNING: Failure to com ly could result in
severe ersonal injury or death and/or ro erty
damage.
3. CAUTION: Failure to com ly could result in
minor ersonal injury and/or ro erty damage.
2. Warranty
Refer to the limited warranty information on the warranty card
included in the "Owner's En elope".
3. Technical Data
Model Sizes 1-20 1-40 1-50 1-65 2-80 2-120 3-180 3-260
110-A 112-A 115-A 118-A 119-A 120-A 122-A 130-A
Maximum Capacity (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
Maximum Temperature Ris e (°F) 120 120 120 120 120 120 120 120
Control Amps (110V) 6666 6 6 6 6
Net Weight (Lbs) 915 925 935 950 1455 1505 2410 2480
General Description (cont d)

Page 3
4. System Dimensions
Figure 1 - Dimensions (inches and mm)
*Measurements for locating ottom air openings are from the edge of the inside of the cur cap. For dimensions to
optional roof cur , see Figure 3.
A
D (Inside the curb cap)
Optional
Return
Air
Opening
Optional
Bottom
Discharge
a
b
b
a
Z
Y
M
N
L
op View
of Curb Cap
(not roof curb)
E
(Inside
the
curb
cap)
R
SPO
a
b
b
a
D (Inside the curb cap)
A (Full length of outside of curb cap)
b
b
a
a
Side View B
1-1/4
(32)
2-5/8
(67)
P
R
SO
Gas Supply
Connection
Gas Vent
Connection
Blower
Compartment
Service Panel
Recommended location
for disconnect switch
24V Control wiring box
Standard
Horizontal
Discharge
CGF
J
H
MN L
E (Inside the curb cap)
K
Front View
Outside Air
Inlet Opening
Rear View
C
V
XB
1-1/4
(32)
ab
2-5/8
(67)
W
Location Key:
a = Recommended locations for disconnect switch and 24 volt control wiring box on Sizes 1-20, 1-40, 1-50, 1-65, 110, 112, 115, 118
b = Recommended locations for disconnect switch and 24 volt control wiring box on Sizes 2-80, 2-120, 3-180, 3-260, 119, 120, 122, 130
Dimensions (inches)
ModelSizes ABCD E F GHJ K L*M
1-20, 1-40, 1-50, 1-65, 110, 112, 115, 118 88-3/8 37-1/8 44-1/4 85-1/4 45-1/2 7-5/8 22 5-3/8 18-7/8 12-7/8 8-1/4 22
2-80, 2-120, 119, 120 88-1/8 48-3/4 68-1/4 85-1/4 69-7/16 16-1/8 27-1/4 6-5/8 27-1/4 14-7/8 16-3/4 27-1/2
3-180, 3-260, 122, 130 136-1/8 61-3/4 82-1/2 132-5/8 83-1/16 14-1/4 37 4 37 20-3/4 14-25/32 37
Model Sizes N* O* P R S* T V W X Y* Z
1-20, 1-40, 1-50, 1-65, 110, 112, 115, 118 15-1/4 12-5/8 19-1/8 17 2-3/8 10-1/16 31-1/8 3 33-5/8 15-1/8 22-1/8
2-80, 2-120, 119, 120 25-3/16 9-5/8 27-1/2 22 6-1/2 10 55-3/16 3 45-9/16 18-1/16 41-7/8
3-180, 3-260, 122, 130 31-5/16 9-3/16 37 30-1/4 11-11/16 12-1/2 67-1/8 3 54-5/8 13-15/16 57-1/8
Dimensions (mm)
ModelSizes ABCD E F GHJ K L*M
1-20, 1-40, 1-50, 1-65, 110, 112, 115, 118 2245 943 1124 2165 1156 194 559 137 479 327 210 559
2-80, 2-120, 119, 120 2238 1238 1734 2165 1764 410 692 168 692 378 425 699
3-180, 3-260, 122, 130 3458 1568 2096 3369 2110 362 940 102 940 527 375 940
Model Sizes N* O* P R S* T V W X Y* Z
1-20, 1-40, 1-50, 1-65, 110, 112, 115, 118 387 321 486 432 60 256 791 76 854 384 562
2-80, 2-120, 119, 120 640 244 699 559 165 254 1402 76 1157 459 1064
3-180, 3-260, 122, 130 794 233 940 768 297 318 1704 76 1387 354 1451

Page 4
5. Accessories - Technical Data and Dimensions
Figure 2 - Optional Outside Air Hoods and Filter Ca inets with and without Filters
Technical Data and Dimensions - inches (mm)
Dimensions - inches (mm) Technical Data
Description/Installation
All of the inlet options (outside air hood and filter cabinets) require field attachment directly to the system cabinet. To prevent damage, it is
recommended that the system be set in its permanent location before installing the air hood or filter cabinet option.
The unit should be positioned so that an outside air hood is not facing into the prevailing wind. A minimum clearance of 14" (356mm) is required
from the bottom of the hood to the mounting surface (roof).
Refer to the chart below for specifications and field requirements of each option.
Refer to Paragraph 15 for assembly and installation instructions.
A
B
C
G
H
D
E
F
1-1/4 (32)
19-1/2
(495)
3 (76)
AS2 Outside Air Hood
AS6 Outside Air Hood with 1" Filters
AS7 Outside Air Hood with 2" Filters
AW3 Indoor Filter Ca inet with 1" Filters
AW6 Indoor Filter Ca inet with 2" Filters
Size 1-20, 1-40, 2-80, 3-180,
1-50, 1-65, 2-120, 3-260,
110, 112, 119, 122,
115, 118 120 130
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* 32-15/16 (837) 56-15/16 (1446) 69-3/8 (1762)
H* 30-3/8 (772) 41-7/8 (1064) 57-7/16 (1459)
*Duct connection
Sizes No. of Filter Size
Filters AS6, AW3 AS7, AW6 AS2 AS6 AS7 AW3 AW6
lbs 225 250 270 100 120
kg 102 113 122 45 54
4 12x35x1 12x35x2 lbs 310 350 380 150 180
4 12x24x1 12x24x2 kg 141 159 172 68 82
12 12x35x1 12x35x2 lbs 400 450 490 200 240
kg 181 204 222 91 109
1-20, 1-40, 1-
50, 1-65, 110,
112, 115, 118
2-80, 2-120,
119, 120
3-180, 3-260,
122, 130
Ap p roximat e Weight
3 12x35x1 12x35x2
Options AS2 AS6 and AS7 AW3 and AW6
Model Sizes 1-20, 1-40, 2-80, 3-180, 1-20, 1-40, 2-80, 3-180, 1-20, 1-40, 2-80, 3-180,
1-50, 1-65, 2-120, 3-260, 1-50, 1-65, 2-120, 3-260, 1-50, 1-65, 2-120, 3-260,
110, 112 119, 122, 110, 112 119, 122, 110, 112 119, 122,
115,118 120 130 115,118 120 130 115,118 120 130
Ship p ed Sep arat ely X X X X X X X X X
FactoryAssembled XXXXXX
Requires Field Assembly X X X
Requires Field Installation X X X X X X X X X
Includes Filters X X X X X X
One Filter Door - Side Opposite Controls only X
Two Filter Doors - Both Sides X X X X X
See instructions
beginning on page 18.

Page 5
Figure 3 - Optional Roof Cur (Option CJ3) - Shipped Separately
Roof Curb Installation Instructions - Option CJ3
CAUTION: Before assembly, 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 above.
1. Position the curb cross rails and curb side rails as shown in the
assembly drawing. Fasten curbing pieces with bolts and lag screws
as illustrated in the corner detail.
2. Check the assembly for squareness. The curb must be adjusted
so that the diagonal measurements are equal within a tolerance of
± 1/8".
3. 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 directions with no twist end to end. Shim as required
and secure curb to the roof deck before installing flashing.
4. Install field-supplied flashing.
5. Before placing the unit into position, apply furnished 1/4" x 1-
1/4" foam sealant tape to the top surface of the curb, making
good butt joints at corners. The unit must be sealed to the curb
to prevent water leakage into the curb area due to blown rain
and capillary action.
Dimensions
Roof Curb and Bottom Duct
Connections - If the system be-
ing installed has a bottom return
air and/or a bottom discharge air
opening, the openings have duct
flanges for connection to field in-
stalled ductwork. This illustration
shows duct opening sizes and spac-
ing in relation to currently manu-
factured optional roof curbs.
Note: Duct openings should be cut
larger than the duct size for instal-
lation clearance.
16
(406mm)
1-7/8 (48mm)
4
(102mm)
2 x 6 Wood Nailer
1-1/2 x 3 lb
Fiberglass
Flashed by he
ins aller (flashing mus
be under lip of curb)
Lag Screw
Cap
Screws
BDA
C
1-7/8
(48)
16 (406)
1-7/8 (48)
1-7/8
(48)
NOTE:
IMPORTANT: Area enclosed by roof curb must com-
ply 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-combustible material which has an "R" value
of at least 5. If area within curb is left open, higher
radiated sound levels may result.
J
G
M
A
Airflow
Direction
Bottom
Return Air
Opening
H
K
LF
C
D
E
B
1-7/8 (48)
1-7/8 (48)
Bottom
Discharge
Air
Opening
Control Side of Heater
Roof Curb
1-7/8 (48)
1-7/8 (48)
Sizes AB CDEFGHJKLM
inches 80-7/8 39-7/8 5-7/16 22 12-7/16 19-1/8 10-7/16 5-7/16 22-1/8 12-5/16 17 3/16
mm 2054 1013 138 559 316 486 265 138 562 313 432 5
inches 80-7/8 63-13/16 13-15/16 27-1/2 22-3/8 27-1/2 7-7/16 6-11/16 41-7/8 15-1/4 22 4-5/16
mm 2054 1621 354 699 568 699 189 170 1064 387 559 110
inches 128 78-5/16 12-13/32 37 28-29/32 37 6-7/8 9-5/8 57-1/8 11-9/16 30-1/4 9-3/8
mm 3251 1989 315 940 734 940 175 244 1451 294 768 238
1-20, 1-40, 1-50, 1-65,
110, 112, 115, 118
2-80, 2-120, 119, 120
3-180, 3-260, 122, 130
Roof Curb Dimensions - inches (mm)
Sizes 1-20, 1-40, 1-50, 1-65, 2-80, 2-120, 3-180, 3-260,
110, 112, 115, 118 119, 120 122, 130
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)
We i gh t 133 lbs (60 kg) 167 lbs (76 kg) 236 lbs (107 kg)

Page 6
6. Uncrating
Immediately upon uncrating the unit, check the gas specifications and
electrical 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 dis-
tributor.
Depending on the gas and/or air controls selected, the following parts
are shipped loose inside the unit.
Gas Controls Shipped-Loose Parts
Standard as Control (A 30) *Remote Temperature Selector
Option A 31 Space Override Thermostat
Option A 32 *Remote Temperature Selector
Option A 33 Remote Temperature Selector
Air Controls Shipped-Loose Parts
Standard Air Control (AR21) None
Option AR19 *Potentiometer
Option AR20 Remote Pressure Sensor
Option AR22 *Potentiometer
Option AR23 Remote Pressure Sensor
*These controls are mounted on the console. The console is shipped
separately.
On Size 3-180, 3-260, 122, and 130 systems, the 24-volt wiring enclo-
sure is packed inside the cabinet for field-installation. The package
includes the enclosure base with waterproof plugs, the enclosure cover,
and hardware. (See Paragraph 11 for installation instructions.)
On all sizes with an optional dirty filter switch, the tubing and clamps
are shipped inside the cabinet.
Be sure that all shipped-separate accessories for the installation are
available. All installations include a remote console. Other shipped-
separate accessories could include a roof curb, an outside air hood, a
disconnect switch, and/or an indoor filter cabinet.
7. 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.
8. 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.
9. Mounting
Mounting the system is the responsibility of the installer. Verify that
the supporting structure has sufficient load-carrying capacity to sup-
port the weight.
NOTE: Net weights are approximate for the standard system. Op-
tional equipment is not included.
Depending on the building and its use, determine whether or not addi-
tional 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 service platform requirements.
Mounting on Field-Supplied Supports
Units may be placed directly on a slab or on a roof where support is
adequate. The curb cap provides required clearance from combustibles.
Mounting on a Roof Curb
CAUTION: Before installation, re-check 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 curb dimension table in Figure 3.
Apply weather stripping or caulking to the roof curb. Lift the unit to
the roof and set it on the curb.
Figure 4 - Sla Mounting
Field
Supplied
Duct
Field
Supplied
Duct
Support Rail 4 x 4 Rail on center
beneath each support rail
= Support leg location
Clearances - inches (mm)
Side Bottom
Top Control Opposite To To
Side Controls Combustibles Non-Combustibles
3 (76) Wi dth
of unit 3 (76) 3 (76) 0 - Curb
Curb
Cap
Roof
Curb
Caulk this surface
before setting unit
on curb.
16
(406mm)
5
(127mm)
1-1/2
(38mm)
Figure 5 - Cur
Mounting
Net Weight of Basic System
Sizes 1-20 1-40 1-50 1-65 2-80 2-120 3-180 3-260
110-A 112-A 115-A 118-A 119-A 120-A 122-A 130-A
lbs 915 925 935 950 1455 1505 2410 2480
kg 415 420 424 431 670 683 1093 1125

Page 7
10. Distribution of Makeup Air
Makeup air can be introduced to the building either through distribu-
tion ducts or through controlled pressurization with little or no duct-
work. Makeup air should be introduced and maintained using the low-
est possible air velocity. With ductwork distribution, this is accom-
plished using a multiplicity of discharge openings over the greatest
centerline distance. When a makeup air system is automatically con-
trolled to maintain a set building pressure, the entering air will travel
naturally toward the relief areas at the perimeter walls using the build-
ing 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.
Always introduce fresh makeup air so that it moves across the greatest
distance within the room or building before reaching an exhauster.
Sizing and Installation of Distribution Ductwork
Proper sizing of warm air ductwork is necessary to ensure a satisfac-
tory heating installation. The recognized authority for such informa-
tion is the Air Conditioning Contractors Association, 1228 17th Street,
N.W., Washington, DC 20036. A manual covering duct sizing in detail
may be purchased directly from them.
nstalling Ducts (See Figure 1 for duct connection dimensions.):
oThe type of duct installation depends in part on the type of con-
struction 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 insu-
lation.
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
installations, the ducts can be slid over the flange of the heater and
then sealed for an airtight and watertight fit. On duct-to-heater con-
nections, use sheetmetal screws to fasten ducts to the heater flange.
Use stiffening flanges around the perimeter of the duct connections.
oReturn Air Duct - The return air duct must be sized for a pres-
sure drop of .5" w.c. at 2850 fpm in order to balance the system.
If not sized properly, there may be difficulty in obtaining the de-
sired air flow over the burner when the return air damper is full
open.
be within approved conduit and have a minimum temperature rise rat-
ing of 60°C. For motor load amps, see Paragraph 13 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.
Disconnect Switch - A safety disconnect is required. Refer to Figure 6
for recommended location and install the disconnect switch in accor-
dance with Article 430 of the National Electrical Code ANSI/NFPA 70.
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 dis-
connect tightly against the heater cabinet.
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 conve-
nience outlet must meet National Electrical Code ANSI/NFPA No. 70
(latest edition) and any local or utility codes that may apply.
Control Wiring
A separate weatherproof field wiring enclosure is provided as the en-
trance of 24-volt control wiring to the electrical compartment. For
locations, see Figure 6, page 8. Low voltage wiring must be in individual
conduit, separated from primary high voltage wiring.
CAUTION: Su ly voltage and 24-volt control
wiring cannot be installed in the same conduit.
Maxitrol systems will be adversely affected if
control wiring is in conduit with su ly voltage
wiring.
A 3-position control switch is the standard switch supplied with each
system, either packed loose inside the unit or mounted on a remote
console.
Control Wiring nclosure
On Sizes 1-20, 1-40, 1-50, 1-65, 2-80, 2-120, 110, 112, 115, 118, and
119, the 24-volt field-wiring enclosure is factory-mounted on the heater.
Remove the cover to facilitate feeding the 24-volt wiring through the
enclosure. When replacing the cover, be careful to slide it under the edge
of the heater to maintain waterproof integrity.
On Sizes 3-180, 3-260,
122 and 130, the 24-volt
field-wiring enclosure is
packed inside the heater for
field installation. The pack-
age contains all items in the
table.
nstructions for nstalling 24-volt Wiring Enclosure
1. Refer to Figure 6, page 8, for mounting location. Loosen the screws
that are in the top side of the cabinet in the selected location. Slide
the field-wiring enclosure base under the edge of the top of the
cabinet.
2. Align the four mounting holes in the enclosure base with the holes in
the cabinet side panel. Attach the enclosure base with four sheetmetal
screws.
3. Insert the Heyco bushing through the side panel of the unit.
4. Feed the 24-volt control wiring through the control-wiring enclo-
sure.
5. To install the enclosure cover, slide the upper edge of the enclosure
cover under the top panel of the cabinet. Place the cover on the base
and secure it using the six remaining sheetmetal screws.
6. Tighten the two screws loosened in Step No. 1.
11. Electrical Supply and
Connections
All electrical wiring and connections including electrical grounding must
be in accordance with the National Electric Code ANSI/NFPA No. 70
(latest edition). Check any local ordinances or utility company require-
ments that apply.
Wire Gauge Sizes -- 100 ft maximum
Full Load Amps 510152025303540
Wire Gauge 141412108866
Run a separate line voltage supply directly from the building electrical
panel to the disconnect switch for the system. All external wiring must
Qty Description
10 1/2 x 10 Sheetmetal Screws
1 SB-1, 500-21 Heyco Bushing
1 Enclosure Base with three plugs
1 Enclosure Cover

Page 8
Recommended Location
for Disconnect Switch 24V Wiring Enclosure
Blower
Compartment
Service Panel
Gas Vent
Connection
Gas Supply
Connection
a
b
b
b
b
a
a
a
Control Side View
Location Key by
Model Size:
a = 1-20, 1-40, 1-50, 1-65
b = 2-80, 2-120, 3-180, 3-260
Figure 6 - Location
of Gas Connection,
Electrical Supply
Connection, and
Control Wiring
Connections
11. Electrical Supply, Connections, and Controls (cont d)
Control Wiring nclosure (cont'd)
2-3/8
(60mm)
6 (152mm)
5-15/32
(139mm)
1-5/16 (33mm)
2-13/32 (61mm)
2-3/8
(60mm)
2-13/32 (61mm)
Control Wiring - Maximum Lengths
Volt s Wire
Gauge
Total Wire
Length
Distance from Unit
to Control
24 18 150 ft (45.7M ) 75 ft (22.9M )
24 16 250 ft (76.2M ) 125 ft (38.1M )
24 14 350 ft (106.7M) 175 ft (53.3M)
Figure 7 - Technical Data of the Remote Console (Variations dependon options selected; consult custom wiring diagram for controls
andto determine wiring required.)
Control Qty of Temperature Potentiometer Dimensions - inches (mm) Locations of Knockout Holes
Switch Lights* Selector** *** L**** H**** D (dimensions to centerlines of holes)
Yes 3 Yes No 10-3/4 (273) 7-3/16 (183) 2-5/8 (67)
Yes 3 No No 10-3/4 (273) 7-3/16 (183) 2-5/8 (67)
Yes 3 Yes Yes 15-3/4 (400) 7-3/16 (183) 2-5/8 (67)
Yes 3 No Yes 10-3/4 (273) 7-3/16 (183) 2-5/8 (67)
Yes 4 Yes No 15-3/4 (400) 7-3/16 (183) 2-5/8 (67)
Yes 4 No Yes 15-3/4 (400) 7-3/16 (183) 2-5/8 (67)
Yes 4 Yes Yes 15-3/4 (400) 7-3/16 (183) 2-5/8 (67)
Yes 4 No No 15-3/4 (400) 7-3/16 (183) 2-5/8 (67)
* 3 - Blower On, Burner On, and Safety Lockout;
4th light is Dirty Filter Indicator
** On the console with Standard Gas Controls, Options AG31, 32, or 33
*** On the console with Air Control Options AR19 or AR22
**** Subtract 5/8" (16mm) when recessing
Control wiring requirements depend on the options selected. Follow the
custom wiring diagram supplied with the system to connect any remote
controls. For additional reference, the control manufacturer's instructions are
included in the owner's envelope.
CAUTION: If any of the original wire must be re laced,
the re lacement wire must have a tem erature rating of
at least 105°C exce t for sensor lead wire which must be
150°C. See Hazard Levels, age 2.
Remote ndicator/Control Console - The remote console is shipped
separately. Remote consoles include terminal blocks for wiring. All
consoles include a 3-position summer/winter/vent switch and three
indicator lights. The lights are labeled "Burner on", Blower on", and
"Safety Lockout". 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 7 for console size.
Dirty Filter Light - 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.
Instructions
oBefore the system is operating, connect the sensing tubes from
the switch to their sensing locations in the field-installed filter cabi-
net. (Cabinet 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.

Page 9
Electric Box
Span
Adjust
Screw
Mounting Plate
Pressure aps
Low
High
Pressure
Adjust Screw
Increasing
Decreasing
Linkage to
Diaphragm
Low
Common
High
Span Adjustment
Span of
floating
contact
Switching action in the pressure null switch
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 8) 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 (Figure 8) 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 sys-
tems; 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 manu-
ally set. With clean filters in place, blower doors closed, and blower
in operation, increase the pressure setting by adjusting the set screw
Figure 9 - Pressure Null Switch
included in Air Control Options
AR20 and AR23
Adjustment of the Switch - The "high"
actuation point of the null switch is indi-
cated on a calibrated scale secured to the
transparent range screw enclosure. Build-
ing pressure is set by turning the adjust-
ment screw. The "low" actuation point is
set by adjusting the span on the null by
turning the span adjustment screw. The
span range is .01 to .03" w.c.
MPORTANT: To eliminate shipping
damage to the switch contacts, the manu-
facturer 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.
Continue 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 sensitivity. The wider the gap,
the lower the sensitivity.
on the switch 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 block-
age.
Pressure Null Switch (applies to systems with Air Control Option
AR20 or AR23) - If the system includes Air Control Option AR20 or
23, a pressure null switch is shipped in the control cabinet. Refer to the
following paragraphs and to the manufacturer's installation instruc-
tions to install and connect this switch.
The pressure null switch is Dwyer #1460-0 with a range of .01-.20"
w.c. The pressure null switch is a diaphragm operated differential pres-
sure switch used in makeup air applications to control building pres-
sure. It maintains a selected positive or negative pressure setpoint by
changing the amount of outside air being introduced to the building
through the modulating 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 position. Conversely, as
less pressure is required, the switch drives the damper in the opposite
direction.
Installation Instructions for Pressure Null Switch (Refer to
Figure 9):
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 dia-
phragm is vertical. Mount switch securely.
Connect the pressure taps on the top of switch to sources of air pres-
sure differential. Metal tubing with 1/4" O.D. is recommended but any
tubing which will not unduly restrict the airflow can be used. To main-
tain 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.
Figure 8 - Dirty Filter
Pressure Switch
Set screw (on
front of switch)
must e manually
adjusted after
system is in
operation.
Negative pressure
connection is toward
the " ack or ottom"
of the switch (senses
blower side of filters)
Positive pressure connection is
toward the "front or top" of the
switch (senses air inlet side of filters)

Page 10
12. Gas Piping and Pressures
All piping must be in accordance with the requirements of the
National Fuel as Code ANSI/Z223.1 (latest edition ) published
by the American as Association. as supply piping installation
must conform with good practice and with all local codes.
Read this section of the installation manual to determine the mini-
mum gas supply pressure required to provide a maximum gas ca-
pacity. Minimum gas supply pressure is also stated on the heater
rating plate. The heater manifold terminates at the gas supply con-
nection with a black iron pipe union. See Figure 10. Local codes
may require a 6" condensate trap. as connection is either 1",
1-1/4", or 2" depending on the size of the system.
WARNING: All com onents of the gas su ly
system must be leak tested rior to lacing
equi ment in service. NEVER TEST FOR
LEAKS WITH AN OPEN FLAME.
High ressure testing of su ly lines is
acce table, rovided the su ly line has been
disconnected from the unit and the i e end is
ca ed. See Hazard Levels, age 2.
Supply Pressure - These direct-fired makeup air systems are de-
signed to operate on a natural gas supply pressure range from 6"
w.c minimum to a maximum of 5 psi. If the natural gas supply
pressure is above the maximum allowed, it is necessary to install a
field-supplied stepdown gas regulator in the supply line. Measure
the gas pressure between the stepdown regulator and the unit. Refer
to the table below for the minimum supply pressure.
Gas Supply Pressure Requirements
Natural Minimum 6" w.c. plus the manifold pressure drop
Gas Maximum 5 psi
Propane Minimum 2" w.c. plus the manifold pressure drop
Gas Maximum 5 psi
Follow the steps and instructions in Paragraph 14, Check-Test-Start, to determine
minimum gas inlet pressure for your specific installation.
Manifold Pressure Drops and Minimum Supply Pressure ( w.c.)
Standard Option BM5 or Option BM9,
MBH Burner Manifold BM7 BM10, or BM11
250 Std 0.9 0.7 N/A
500 BL2 2.3 1.9 N/A
750 BL3 6.8 3.9 N/A
1000 BL4 N/A N/A 3.0
1250 BL5 N/A N/A 4.0
1500 BL6 N/A N/A 5.1
1750 BL7 N/A N/A 6.6
2000 BL8 N/A N/A 8.0
2250 BL9 N/A N/A 2.5
2500 BL10 N/A N/A 2.9
2750 BL11 N/A N/A 3.3
3000 BL13 N/A N/A 3.8
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.
From Gas Supply
From
Gas
Supply
6 Drip Leg
NO E:
Connections
shown are by
the installer.
o Burner and
Controls
Manual
Gas Valve
A manual shutoff valve and an adapter with a
1/8"  NP plugged hole for test gauge
connection must be installed immediately
upstream of the gas supply connection to
the appliance.
Ground
Joint
Union
1/8 NP
NO E: o permit
burner removal this
nipple must extend
beyond the edge
of the heater
Manifold Pressure - Manifold pressure is defined as the
gas pressure as measured at the burner pressure tap. Mea-
sure manifold gas pressure with the blowers operating.
Minimum gas supply pressure is determined by adding 6"
w.c. (minimum required) plus the pressure drop through
the manifold.
Optional Gas Pressure Switches - as pressure switches
included in the system's gas train monitor gas pressure
downstream from the safety valves. If the gas pressure at
this point on a system equipped with a high gas pressure
switch (Option BP2) 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: On units manufacturing beginning April
1993, gas pressure switches incorporate a vent limiting
device and do not require venting to the outdoors when
used in an application installed indoors. Indoor units manu-
factured prior to April 1993 with optional gas pressure
require a 3/4" vent line to the outdoors.)
Gas Vent Piping for Optional Vent Valve (applies only
to an indoor installation with Manifold Option BM7 or
BM11) - When a system installed indoors is equipped
with an optional vent valve (part of manifold Option BM7
and 11), piping must be field-installed to terminate the vent
outdoors. Locate the 3/4" male pipe threads protruding
from the intermediate post next to the control compart-
ment. Extend the 3/4" piping to the outside of the building
and terminate with a screen.
CAUTION: Gas i ing connections are determined
by burner BTU. Use this table as reference for i e
connection at the unit only.
Figure 10 - Gas
Supply Connection
Gas Pipe Connections at the Unit
Burner Size MBH Burner Option Pipe Size
250 - 750 BL2, BL3 1" IP
>750 - 2,000 BL4, BL5, BL6 ,BL7, BL8 1-1/4" IP
>2,000 - 3,000 BL9, BL10, BL11, BL13 2" IP

Page 11
Gas Supply Piping
13. 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 11). Tighten the lock
nut on the adjusting screw. Be sure the belt is aligned in the pulleys.
3/4 (19mm)
Figure 11 -
Belt
Tension
Motor and Belt Shipping Position for Sizes 2-80, 2-120, 3-180, 3-260,
119, 120, 122, 130 - 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 ship-
ment. Install the belt(s) and adjust for proper belt tension.
Blower Pulley - Size 2-80, 2-120, 119
and 120 systems equipped with 3 and 5
HP motors with a 15.4" diameter and
larger blower pulley or a 7-1/2 HP and
larger motor and all Size 3-180, 3-260,
122, and 130 systems are equipped with
a split taper bushing in the blower pul-
ley. 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 12).
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
3 Cap
Screws
Figure 12 - Split Taper
Bushing
2 Push-Off Holes
system, the blower RPM may have to be changed. Motors are
equipped with adjustable pitch pulleys which permit adjustment
of blower speed. Instructions are included in Paragraph 14, Check-
Test-Start for adjusting blower speed.
Blower Rotation - Each blower housing is marked for proper
rotation. Instructions for checking blower rotation are included in
the Check-Test-Start Procedure in Paragraph 14.
Motor Loads - Use an ammeter to check motor amps. Amps may
be adjusted downward by reducing blower RPM or by increasing
duct system static pressure. For accurate amps, read the motor
manufacturer's rating plate; amps will vary depending upon mo-
tor manufacturer. The chart below can be used for sizing line
wiring.
CAUTION: The a ove chart lists full load amp
requirement of standard motor and standard controls.
Optional controls will increase amp requirement. Add
motor amps and control amps for approximate unit full
load amps. System FLA are shown on the rating plate.
Capac i ty of Pi pi ng
Cubic Feet per Hour 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 Diameter of Pipe
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 . Refer to National Fuel Gas Code for additional information on line s izing.
Blower Motor Full Load Amps (open motors)
Motor 1 phase 3 phase
HP 115V 230V 208V 230V 460V 575V
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
2 N/A N/A 7.5 6.8 3.4 2.4
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
110V Std
Control Amps 6.0 3.0 3.4 3.0 1.5 1.2

Page 12
14. Check-Test Start
Sizes 2-80, 2-120,
3-180, 3-260,
119, 120, 122,
130
In the electrical compartment - Sizes 1-20, 1-40, 1-50, 1-65,
110, 112, 115, 118
Outside
Air Hood
(required on
outdoor
installations)
Outside Air Control
810 81
8
3
4
5
6
2
7
9
Sizes 2-80, 2-120, 3-180,
3-260
,
119
,
120
,
122
,
130
Figure 13A
KEY:
1 - Burner
2 - Discharge Damper Motor (Options
AR19 & 20)
3 - Discharge Damper (Options AR19
& 20)
4 - Manual Reset Limit
5 - Automatic Limit
6 - Discharge Air Sensor
7 - Blower Motor
8 - Damper Motor (Optional)
9 - Return Air Damper (Options AR22
& 23)
10 - Bypass Damper (Options AR19,
20, 22 & 23)
Sizes 2-80, 2-120, 3-180, 3-260, 119, 120, 122, and 130
Figure 13B - Electrical Compartment (Optional diagnostic status light board is not shown.)
Sizes 1-20, 1-40, 1-50, 1-65, 110, 112, 115, and 118
Outside
Air Cutoff Maxitrol
Amplifier
Burner Bypass
Damper Motor
(optional)
Service
Switches
Low Voltage erminal Blocks
24V ransformer
Ignition Module
Contactor
or Starter
115V ransformer
Fuse and
Fuseholder
High Voltage erminal Blocks
Control Relays
Low Fire
ime Delay
Prepurge
ime Delay Relay
Setting
.2 w.c.
Low Air
Pressure Switch
Pressure Switch
Pressure SwitchPressure Switch
High Air
Bypass DamperBypass Damper
Setting
.9 w.c.
Normally open;
Setting .65 w.c.
Normally closed;
Setting .5 w.c.
Service
Switches
Normally
closed;
Setting
.5 w.c.
Normally
open;
Setting
.65 w.c.
Setting
.9 w.c.
Setting
.2 w.c. Ignition Module
High Voltage erminal Blocks
Low Voltage erminal Blocks
Fuse and
Fuseholder
24V ransformer
Maxitrol
Amplifier
Low Air
Service
Switches
Contactor
or Starter
Control Relays
Low Fire
ime Delay
Prepurge
ime Delay
Pressure Switch Pressure Switch
Bypass Damper
Bypass Damper
Pressure Switch Pressure Switch
High Air

Page 13
Check/Test/Startup Procedures (Follo Steps in Sequence)
KEY : oProcedure a lies to all units.
¡Procedure only a lies to units with the o tional com onent referred to in that rocedure
Before Startup
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 maximum total input amps. Verify continuity of fuses.
7. Open the gas and electric control compartment door panels --
oClose all manual gas al es.
oCheck all wiring and wiring connections on gas controls and electrical components.
oIf equipped with any manually reset de ices such as an optional firestat limit switch, a high limit switch, and/or optional high
gas pressure switch, reset de ices. Check setpoint on the outside air control (60°F).
8. In the blower compartment --
oRemo e any blocking and shipping supports.
oCheck that the blower belts are installed and ha e correct tension and that pulleys are in alignment and locked to the shaft
(See Paragraph 13).
Inside the compartment, remo e the co er 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 co er.
9. Turn ON gas supply valve and inlet manual shutoff valve on the manifold --
oLeak test gas connections upstream of the electric gas al e. Be sure all connections are tight and leak tested. WARNING:
DO NOT TEST WITH OPEN FLAME.
oTurn OFF manual gas al es.
10. Turn blower service switch (Electrical Compartment See Figure 13) to OFF position. If present verify that
damper test switch is in TEST position.
Startup
1. Prepare system for startup testing --
oAttach a slope gauge (0 to 1.0" scale) to the tubing connections in the control compartment. Disconnect plastic tubing from
high and low air pressure connections (mark tubing) in electrical control compartment. Connect slope gauge between the
high and low pressure connections. (Located in the gas control compartment, the
high pressure connection is on the right, low pressure is on the left.)
oConnect a "U"-tube manometer to the main burner pressure tap.
¡Check optional status lights (If the system is equipped with an optional
lighted status board (Option BS2), check the lights at each step in the Startup
procedure.)
Turn ON disconnect switch.
If equipped with optional status lights, check the lighted status panel - "Circuit
Control Power" light is lit.
Turn OFF disconnect switch.
oTurn the disconnect switch ON and the blower ser ice switch to TEST position.
¡ If equipped with optional status lights, check for lights - "Control Switch Ener-
gized", "Starter Energized", and if equipped with a freezestat, "Freezestat". After
blower obtains normal speed, check for these lights - "Outside Air Cutoff Normal";

Page 14
14. Check-Test Start (cont d)
Startup (cont'd)
o Turn on the disconnect switch and re-check the slope gauge. If air pressure differential is within the limits of -.5" to -.65" w.c., no
further adjustment is required. If the air pressure differential is not within those limits, re-adjust the blower speed.
o When the differential air pressure is within the limits, check the motor amp draw with an ammeter to be sure that the motor is not
o erloaded. Amps are shown on the motor nameplate.
o Record the negati e pressure reading (blower operating) on the manometer in the gas line. (This measurement will be needed if
Startup Step 5 is required.)
oIf an inlet or outlet duct system is attached to the heater, run the blower to purge the olume of air from the duct system with at
least four air changes.
oTurn the blower switch to OFF and damper test switch to RUN. Turn the disconnect switch OFF. Disconnect the manometer and
the slope gauge. Reconnect the tubing to the correct pressure connections.
"Low Air Pressure Normal", "Limit Controls Normal"; "High Air Pressure Normal"; and if equipped with options; "Low Gas
Pressure Normal"; and/or "High Gas Pressure Normal")
oCheck for blower rotation. If the blower is turning backwards (see rotation arrows), do the following:
Turn the disconnect switch OFF
Single-phase units -- rewire motor per instructions on motor wiring plate
Three-phase units -- interchange any two motor leads at the motor contactor or starter
Turn disconnect switch ON and verify rotation.
2. Measure (1) burner differential air pressure on the slope gauge and (2) the negative pressure created in the gas
line by operation of the blower. With the blower operating differential air should read between -.5" and -.65" w.c.
If the slope gauge reading is not within the limits of these numbers do one of the following:
If the slope gauge reading is greater than -.5" (such as -.3"
w.c.), adjust the drive to increase the lower speed.
(1) Turn disconnect switch OFF.
(2) ¡ If equipped with a discharge damper, remove opposite side
blower door panel.
Turn disconnect switch ON.
Check that discharge damper is full open by loosening or tight-
ening the linkage.
Turn disconnect switch OFF.
Replace door panel.
Turn disconnect switch ON and recheck slope gauge.
Turn disconnect switch OFF.
(3) If reading is still greater than -.5" w.c., adjust drive to increase fan
RPM.
For systems with smaller than 7-1/2 HP motor
(a) Loosen belt tension and remove belt.
(b) Loosen the set screw 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 screw on the flat portion of the pulley shaft.
For systems with 7-1/2 HP and larger motor
(a) Slack off all belt tension by moving the motor toward driven
shaft until the belts are free of grooves. For easiest adjust-
ment, remove the belts from the grooves.
(b) On the outer locking ring, locate the two locking screws that
are directly across from each other. Loosen, but do not re-
move, those two screws. Do not loosen any other screws.
(c) Adjust sheave to desired pitch diameter by turning the outer
locking ring. One complete turn of the outer locking ring will
result in .233" change in pitch diameter. To increase blower
speed, decrease diameter. CAUT ON: Do not adjust sheaves
in either direction to the point where moveable and station-
ary flanges are in contact.
(d) Re-tighten the locking screws.
All Motor Sizes - Replace the belts and check belt tension. Be
sure that belts are aligned in the pulley grooves and are not angled
from pulley to pulley.
If the slope gauge reading is less than -.65" (such as -.9" w.c.),
adjust the drive to decrease the lower speed.
(1) Turn disconnect switch OFF.
(2) ¡ If equipped with a discharge damper, remove opposite side
blower door panel.
Turn disconnect switch ON.
Check that discharge damper is full open by loosening or tighten-
ing the linkage.
Turn disconnect switch OFF.
Replace door panel.
Turn disconnect switch ON and recheck slope gauge.
Turn disconnect switch OFF.
(3) If reading is still less than -.65" w.c., adjust drive to decrease fan
RPM.
For systems with smaller than 7-1/2 HP motor
(a) Loosen belt tension and remove the belt.
(b) Loosen the set screw on the side of the pulley away from the
motor.
(c) Turn the adjustable half of the pulley outward to decrease
blower speed. One turn of the pulley will change speed 8% to
10%.
(d) Tighten the set screw on the flat portion of the pulley shaft.
For systems with 7-1/2 HP and larger motor
(a) Slack off all belt tension by moving the motor toward driven
shaft until the belts are free of grooves. For easiest adjustment,
remove the belts from the grooves.
(b) On the outer locking ring, locate the two locking screws that are
directly across from each other. Loosen, but do not remove,
those two screws. Do not loosen any other screws.
(c) Adjust sheave to desired pitch diameter by turning the outer
locking ring. One complete turn of the outer locking ring will
result in .233" change in pitch diameter. To decrease blower
speed, increase diameter. CAUT ON: Do not adjust sheaves in
either direction to the point where moveable and stationary
flanges are in contact.
(d) Re-tighten the locking screws.
All Motor Sizes - Replace the belts and check belt tension. Be sure
that belts are aligned in the pulley grooves and are not angled from
pulley to pulley.

Page 15
D T RMIN the type of gas control system from the unit rating plate:
Serial No. Suffix Option Gas Control System
MV7 AG30 or AG31 Maxitrol Series #14 (Amplifier A1014)
MV8 AG32 Maxitrol Series #14A (Amplifier A1014)
MV9 AG33 Maxitrol Series #44 (Amplifier A1044)
MVC AG37 Maxitrol Series #DDC (Signal Conditioner A200)
For units with Maxitrol Series 14 or 14A, remo e and indi idually tape wires from Terminals #4 and #8 on the amplifier
For units with Maxitrol Series 44, remo e and indi idually tape wires from Terminals #2, #4 and #8 on the amplifier
For units with Maxitrol Series DDC, the customer pro ided input signal must be 4-20 milliamps (conditioner dip switch "on")
or 0-10 olt DC (conditioner dip switch "off").
IMPORTANT NOT : The instructions in 3A are designed for systems manufactured after 3/96 equipped with hot
surface ignition. If the system being started is equipped with a spark pilot and a flame rectification or ultraviolet flame
sensor follow instructions in 3B.
3A. Check pilot and burner ignition and pilot operation (hot surface ignition)
oTurn the disconnect switch ON. Turn blower ser ice switch and burner ser ice switch to TEST
position.
oObser e for ignition through the iewport.
¡ If equipped with optional status lights, check for lights - Lights listed in prior Steps should be ener-
gized). After 15-20 seconds, the "Pilot Valve" light will light to signal the pilot ignition, followed by
the "Main Valve" light signaling main burner operation.
oWith both the burner and blower operating, measure the gas pressure at the burner. Gas pressure
should match the required manifold pressure listed on the rating plate. (If pressure does not match the
required pressure, further testing is required in Step 5.) Remo e the manometer.
oLeak test all connections in the pilot and main burner supply lines. WARNING: DO NOT TEST WITH
OPEN FLAME.
oCheck output of pilot flame signal. Use microampmeter; reading should be .5.
oTo check lockout feature of the pilot ignition system, turn pilot manual shutoff al e OFF. Pilot should
lockout after two trials for ignition. To reset unit, open the al e and cycle the main disconnect switch.
oTurn OFF the manual gas al e. Wait 30 seconds for unit to cool. Return both burner and blower
switch to OFF position. Turn OFF disconnect switch.
3B. Check pilot and burner ignition and pilot operation
oRemo e co er from flame safeguard relay (in the electrical compartment).
oDisconnect and tape orange wire from Terminal C on 115 olt terminal strip leading to flame safeguard
relay. Wire must be taped. This disrupts power to safety al e(s) after establishing pilot.
oJumper Terminals K and L on 115 olt terminal block. This bypasses outside air cutoff.
oOpen main, pilot and leak test shutoff al es.
oTurn the disconnect switch ON. Turn blower ser ice switch and burner ser ice switch to TEST
position.
oObser e pilot for spark and ignition through the iewport.
oTurn pilot manual shutoff al e OFF. After pilot goes out, flame safeguard relay should lockout.
oTurn disconnect switch OFF and burner ser ice switch to OFF. Reset flame safeguard relay and replace
co er. Turn pilot manual shutoff al e ON. Reconnect wire to Terminal C on 115 olt terminal block
from the flame safeguard relay. Turn disconnect switch ON. Turn burner ser ice switch to TEST
position. Obser e spark and pilot operation. Obser e "low-fire" start. Burner should lightoff across
the whole length.
¡ If equipped with optional status lights, check for lights - Lights listed in prior Steps should be ener-
gized). After 15-20 seconds, the "Pilot Valve" light will light to signal the pilot ignition, followed by
the "Main Valve" light signaling main burner operation.
oUsing microampmeter, check the output of pilot flame at flame safeguard relay. (May require a flame
current test jack.)
Type of Flame Sensor Microamps
RA890F (Flame Rectification) 2.0-5.0
RA890G (Ultra iolet) 1.5-3.0
R7795A (Ultra iolet) 3.5-7.5
R7795B (Flame Rectification) 2.0-5.0

Page 16
14. Check-Test Start (cont d)
Startup (cont'd)
oWith both the burner and blower operating, measure the gas pressure at the burner. Gas pressure
should match the required manifold pressure listed on the rating plate. (If pressure does not match the
required pressure, further testing is required in Step 5.) Remo e the manometer.
oLeak test all connections in the pilot and main burner supply lines. WARNING: DO NOT
TEST WITH OPEN FLAME.
oTurn disconnect switch OFF. Reconnect wire to Terminal #8 on the amplifier. Turn disconnect
switch ON. Obser e burner. Unit should stage through spark, pilot, low-fire, and then go to
high-fire.
oTurn OFF the manual gas al e. Wait 30 seconds for unit to cool. Return both burner and
blower switch to OFF position. Turn OFF disconnect switch.
4. Check pilot pressure (hot surface ignition units only) --
oTo check pilot gas pressure, connect a "U"-tube manometer to the pressure tap on the
downstream side of the pilot solenoid al e.
oPut BOTH the blower and burner switch in TEST position. Turn ON disconnect switch.
Blower should be energized.
oMeasure pilot gas pressure. Pilot pressure for natural gas should be 3.5" w.c.; pilot pressure
for propane gas should be 6" w.c. Pilot pressure should be correct, but if the pressure is not
correct, discontinue startup until the pilot gas pressure is regulated correctly.
(To adjust pilot pressure, remo e the cap from the regulator. Turn adjustment clockwise to increase gas pressure or counter-
clockwise to decrease gas pressure.) When pressure is correct, shut off the gas, remo e the manometer, and replace the
pressure tap cap on the pilot solenoid al e.
5. If, with the blower and burner operating the main gas pressure measured in Step 3 does not correspond with
what is stated on the rating plate check the main burner gas differential pressure.
oTurn disconnect switch OFF.
oRe-connect the "U"-tube manometer to the main burner pressure tap.
oTurn pilot manual shutoff al e back ON.
oTurn the disconnect switch ON; ignition sequence will occur.
oObser e the main burner. Light off should occur along the entire length of the burner.
oAfter approximately one minute, record the gas pressure reading on the manometer. NOTE: High outside air temperature on high
fire may cause the automatic high limit to trip. Manometer reading may only be a ailable for a ery short time.
oTurn disconnect switch OFF.
oRemo e the manometer and replace the plug.
Startup for Continuous Operation
oSystem with flame rectification or ultraviolet sensor (manufactured prior to 3/96) recon-
nect wires to Terminals #2 and #4 on the amplifier.
oRemove all jumper wires and reconnect wires.
oVerify that the blower burner and damper switches are in RUN position. CAUTION: If
blower or burner service switches are left in TEST position they will override control from
the remote console switch or automatic control.
oCheck that all manual valves are ON.
oClose the control door panel; secure latches.
Calculate the required burner differential gas pressure --
Factor 1 - Actual as Pressure Reading with blower and burner oper-
ating (just recorded)
Factor 2 - Negative pressure Reading in the gas line with blower
operating as recorded in Startup Step 2
Ignoring the minus, deduct the negative pressure from the actual gas
pressure. EXAMPLE: as Pressure Reading 5.7" w.c.
Negative Pressure -.6" w.c.
Differential Pressure 5.1" w.c.
Differential gas pressure is the figure used when determining mini-
mum gas supply pressure. Add differential gas pressure plus the drop
in gas pressure as it flows through the gas train (See Paragraph 13) to
determine the minimum required supply pressure of inlet gas.
For maximum firing rate, a minimum of 5" w.c. of actual measured
natural gas pressure is required at the burner. (If maximum firing rate
is not required, divide the actual input rate by the maximum rate,
square the answer, and multiply by 5" w.c. to determine the required
gas pressure at less than maximum capacity.)

Page 17
oTurn ON the disconnect switch. The system is now operational from the control switch
the remote console or other type of optional automatic control. CAUTION: Burner will
not operate if ambient air temperature is above setpoint of outside air control (factory
setting is 60°F).
After Startup
oReturn this manual to the owner's envelope. Keep for future reference.
oTo check for toxic vapors coming from the surrounding outside atmosphere or being
produced by the installation (See DANG R below) it is recommended that the tempered
makeup air entering the building be tested at its point of discharge from the heating unit.
The table below shows limits for various substances including carbon monoxide.
Certified portable detector tubes may be used; follow the manufacturer's instructions.
Limits Based on Eight -Hour Exposure and a Fi e-Day Week (Guide Only)
Substance Percent PPM
Acetaldehyde .001 10
Carbon Dioxide .250 2500
Carbon Monoxide .001 10
Formaldehyde .000025 0.25
Nitrogen Dioxide .0001 1
Sulphur Dioxide .00005 0.5
Note: At 100°F rise the CO2 concentration will be in the order of 2500 ppm.
DANGER: The gas burner in this direct gas-fired system is designed and equi ed to rovide safe and
economically controlled com lete combustion. However, if the installation does not ermit the burner to
receive the ro er su ly of combustion air, com lete combustion may not occur. The result is incom lete
combustion which roduces carbon monoxide, a oisonous gas that can cause death.
Always com ly with the combustion air requirements in the installation codes and o erating instructions.
The amount of air over the burner must be within the s ecified range. The burner rofile lates are set at
the factory to match CFM requirements. Do not adjust the burner rofile lates without contacting a
factory re resentative. FAILURE TO PROVIDE PROPER COMBUSTION AIR CAN RESULT IN A
HEALTH HAZARD WHICH CAN CAUSE PROPERTY DAMAGE, SERIOUS INJURY, AND/OR
DEATH. Direct-fired installations should rovide for air changes as required by the a licable installation
codes.

Page 18
Field Installed Accessories
15. Optional Screened Air Hood for outdoor Units (Options AS2, AS6,
AS7) and Filter Sections for Indoor Units (Options AW3, AW6)
All of these air inlet accessories are designed to be attached directly to the system cabinet. All are shipped separately and require field installation.
See Paragraph 5 for a brief description and the dimensions of these optional accessories.
CAUTION: It is recommended that the inlet to the outside air hood NOT be facing into revailing wind.
Provide a minimum of 14" clearance from the bottom of the air hood to the mounting surface.
1) Remove the sheetmetal
screws from the bottom
rear inset and across the
top rear of the cabinet.
2) Align edges of assembly to the slip
grooves. Slide top edge of assembly
under the lip formed by the top rear of
the cabinet.
3) Rotate the inlet assembly so that it
fits into the recess across the bottom
of the cabinet. Replace all screws re-
moved in Step 1.
4) If the system has filters with an op-
tional dirty filter light, follow the in-
structions on page 9 to attach the sens-
ing tubes.
Installation Instructions for Items 1 and 3 above
S EP 2
S EP 3
nstructions for nstalling tem 2 above è
Remove sheetmetal
screws
Slip
Groove
Remove
sheetmetal
screws
Item Options Description For Sizes Installation Requirements
1 AS2, AS6, AS7 Outdoor Screened Air Hood with
and without filters
1-20, 1-40, 1-50, 1-65, 2-80, 2-120,
110, 112, 115, 118, 119, 120
Factory Assembled; Field Installed -
Follow instructions below.
2 AS2, AS6, AS7 Outdoor Screened Air Hood with
and without filters
3-180, 3-260, 122, 130 Field Assembled and Installed -
Follow instructions pages 19 to 22.
3AW3,AW6 Indoor Filter Cabinet with Filters All Factory Assembled; Field Installed -
Follow instructions below.

Page 19
Installation Instructions for Item 2 on page 18
Option AS2 Outdoor Screened Air Hood without Filters - Pkg P/N 71150
Option AS6 Outdoor Screened Air Hood with 1" Filters - Pkg P/N 71152
Option AS7 Outdoor Screened Air Hood with 2" Filters - Pkg P/N 72627
Step 1A - Assemble Inner Side of
Filter Rack (Applies to Options AS6
and AS7 only; for Option AS2
without filters, proceed to Step 1D)
Parts Required -- Right corner post, left corner
post, three of the five pre-assembled center filter
channels, and twelve 1/2" long screws
Corner posts come with two sets of holes.
For 1" filters (Option AS6), attach the three fil-
ter channel assemblies using the holes in the corner
posts closest to the inside.
For 2" filters (Option AS7), attach the three fil-
ter channel assemblies using the holes in the corner
posts closest to the outside edge.
Pre-assembled Center Filter Channels
(NOTE: There are five cen er fil er channels
.
The o her wo are used on he o her side of
he fil er rack in S ep 1C)
P/N 91579
Corner Post
P/N 91579
Corner Post
(See Paragraph 5 for dimensions and weights.)
Assembly and Installation Instructions (Do not install hile system is operating.)
1. Screened Air nlet Hoods with Filters (Options AS6 and AS7 for Sizes 3-180, 3-260) - Build filter racks and cabinet section; follow all Steps.
Screened Air nlet Hood without Filters (Option AS2 for Sizes 3-180, 3-260) - Build cabinet section; skip Steps 1A, 1B, and 1C. Start with
Step 1D ignoring filter rack illustrations.
Components Option AS2 Option AS6 Option AS7
Qty P/N Qty P/N Qty P/N
Top of Inlet Hood Cabinet Section 1 91575 1 91575 1 91575
Top of Inlet Hood 1 91576 1 91576 1 91576
Clamp for Top Seam (Hood to Cabinet) 1 91577 1 91577 1 91577
Bottom of Hood Cabinet Section 1 91567 1 91567 1 91567
Supports (2 pieces per leg) 6 91581 6 91581 6 91581
Left Side of Hood 1 91568 1 91568 1 91568
Right Side of Hood 1 91569 1 91569 1 91569
Intermediate Posts - Cabinet Section 2 91578 2 91578 2 91578
Right Corner Post - Cabinet Section 1 91579 1 91579 1 91579
Left Corner Post - Cabinet Section 1 91579 1 91579 1 91579
Doors (Filter Access on AS6 and AS7) 2 91585 2 91585 2 91585
Center Louver Top/Bottom Supports 2 91582 2 91582 2 91582
Factory-assembled Louver Sections with Screens 2 113003 2 113003 2 113003
Top and Bottom Filter Channels N/A 2 91580 2 94224
Pre-assembled Center Filter Channels N/A 5 91586 5 94223
Top Filter Block Off Plate N/A 1 91584 1 98764
Bottom Filter Block Off Plate N/A 1 91584 1 98764
Filter Block Off Sections N/A 6 95335 6 96335
Permanent Filters N/A 12 1", 87251 12 2", 94383
Sheetmetal Screws #10 x 1/2" long 100 11813 100 11813 100 11813
Screws 1/4-20 x 5/8" long (bolt type) 15 10393 15 10393 15 10393
Hex Nuts 1/4-20 (Keps) 15 7328 15 7328 15 7328
Sheetmetal Screws #14-110 x 3/4" long 3 41463 3 41463 3 41463
Tinnerman Clip, Palnut #PW-1880-008-21 5 87900 5 87900 5 87900

Page 20
op Filter channel
Bottom Filter
Channel op Blockoff
Plate
Bottom Blockoff
Plate
Step 1 B - Sup-assemble Top
and Bottom Filter Channels and
Filter Blockoff Plates (AS6 & AS7)
Parts Required - Top and bottom filter channel; top and bottom
filter blockoff plates; and 14 screws (1/2" long)
Assemble the top blockoff plate and the top filter channel being
sure the filter channel groove is on the same side as the 90° bend in
the blockoff plate but directed away from it. Use seven screws to
attach the top blockoff plate to the top filter channel. Repeat the
process with the bottom filter channel and bottom blockoff plate.
op Filter Channel with
Blockoff Plate (assembled in 1B)
Center Channel Assy
P/N 91578
Intermediate
Cabinet 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 Required - Two intermediate posts; two remaining pre-as-
sembled center filter channels; the top and bottom filter channel/
blockoff plate assemblies form Step 1B; and 12 sheetmetal screws
(1/2" long)
For 1" filters (Option AS6), attach the channel assemblies to the
holes closest to the inside of the intermediate posts.
For 2" filters (Option AS7), attach the channel assemblies to the
holes closest to the outside edge of the posts.
P/N 91575 op of Inlet
Hood Cabinet Section
Intermediate
Post
Corner
Post
Intermediate
Post
Corner
Post
Step 1D - Attach Cabinet Section To Corner
Posts and Intermediate Posts (Options AS2,
AS6, and AS7)
Parts Required - Cabinet top; the two corner cabinet posts (if inlet
hood with filters, posts will be sub-assembled to filter channels -
Step 1A) (if AS2 with no filters, ignore illustrated filter rack); the
two intermediate cabinet posts (if inlet hood with filters, posts will
be sub-assembled to filter channels - Step 1C); and six 1/2" long
sheetmetal screws.
Attach cabinet section top to the four posts as illustrated.
Step 1 - Attach Cabinet Section Bottom
Parts Required - Subassembly from Step 1D; cabinet section
bottom; and six 1/2" sheetmetal screws.
Position the cabinet section bottom to the inside of the four posts
(corners). Attach as illustrated.
Assembly and Installation Instructions (cont'd)
P/N 91567
Bottom of Hood
Cabinet Section