Bryant 345MAV User Manual

installation, start-up, and operating instructions

4-WAY MULTIPOISE FIXED-CAPACITY CONDENSING GAS FURNACE

345MAV

Series F

Cancels: II 345M-40-7 II 345M-40-8

12-03

AIRFLOW

UPFLOW

A93040

NOTE: Read the entire instruction manual before starting the installation.

This symbol → indicates a change since the last issue. Table of Contents Page

DIMENSIONAL DRAWING........................................................2

SAFETY CONSIDERATIONS.....................................................3

Clearances to Combustibles......................................................3

CODES AND STANDARDS........................................................4

ELECTROSTATIC DISCHARGE (ESD) PRECAUTIONS........5

INTRODUCTION..........................................................................5

APPLICATIONS............................................................................5

General......................................................................................5

Upflow Applications.................................................................6

Downflow Applications............................................................7

Horizontal Left (Supply-Air Discharge) Applications ............9

Horizontal Right (Supply-Air Discharge) Applications........11

LOCATION..................................................................................12

General....................................................................................12

Furnace Location Relative to Cooling Equipment................13

Hazardous Locations...............................................................13

AIR FOR COMBUSTION AND VENTILATION....................13

General....................................................................................13

Unconfined Space...................................................................14

Confined Space.......................................................................14

INSTALLATION.........................................................................15

Leveling Legs (If Desired).....................................................15

Installation In Upflow or Downflow Applications................17

Installation In Horizontal Applications..................................17

Air Ducts.................................................................................17

General Requirements .......................................................17

Ductwork Acoustical Treatment .......................................17

Supply Air Connections....................................................17

Return Air Connections.....................................................18

Filter Arrangement ............................................................18

Bottom Closure Panel........................................................19

Gas Piping..........................................................................19

Electrical Connections............................................................20

115-v Wiring......................................................................21

24-v Wiring........................................................................21

Accessories ........................................................................22

Venting....................................................................................22

Removal of Existing Furnaces from Common

Vent Systems.....................................................................22

Combustion-Air and Vent Piping .....................................23

Vent Termination...............................................................31

Multiventing.......................................................................31

—1—

AIRFLOW

HORIZONTAL

LEFT

DOWNFLOW

AIRFLOW

HORIZONTAL

RIGHT

AIRFLOW

Fig. 1—Multipoise Orientations

As an ENERGY STAR® Partner, BRYANT Heating & Cooling Systems Company has determined that this product meets the ENERGY STAR® guidelines for energy efficiency.

ama

REGISTERED QUALITY SYSTEM

CERTIFIED

Condensate Drain....................................................................31

General...............................................................................31

Application.........................................................................33

Condensate Drain Protection.............................................33

START-UP, ADJUSTMENTS AND

SAFETY CHECK...................................................................33

General...............................................................................33

Prime Condensate Trap With Water.................................34

Purge Gas Lines ................................................................34

Sequence of Operation......................................................34

Heating Mode...............................................................34

Cooling Mode...............................................................35

Continuous Blower Mode............................................35

Heat Pump Mode .........................................................35

Component Test ...........................................................35

Adjustments .......................................................................36

Set Gas Input Rate.......................................................36

Set Temperature Rise...................................................40

Blower Off Delay (Heat Mode) ..................................41

Set Thermostat Heat Anticipator.................................41

Check Safety Controls.......................................................41

Check Primary Limit Control......................................41

A93041

Check Pressure Switch.................................................41

CHECKLIST......................................................................42

SAFETY CONSIDERATIONS

CAUTION: Application of this furnace should be in-

doors with special attention given to vent sizing and material, gas input rate, air temperature rise, unit leveling, and unit sizing. Improper installation or misapplication of furnace can require excessive servicing or cause premature component failure.

WARNING: Improper installation, adjustment, alteration, service, maintenance, or use can cause carbon monoxide poisoning, explosion, fire, electrical shock, or other conditions which may cause personal injury or property damage. Consult a qualified installer, service agency, local gas supplier, or your distributor or branch for information or assistance. The qualified installer or agency must use only factory-authorized and listed kits or accessories when modifying this product. Failure to follow this warning could result in electrical shock, fire, personal injury, or death.

Installing and servicing heating equipment can be hazardous due to gas and electrical components. Only trained and qualified

personnel should install, repair, or service heating equipment.

Untrained personnel can perform basic maintenance functions such as cleaning and replacing air filters. All other operations must

be performed by trained service personnel. When working on heating equipment, observe precautions in literature, on tags, and on labels attached to or shipped with unit and other safety precautions that may apply.

These instructions cover the minimum requirements and conform to existing national standards and safety codes. In some instances, these instructions exceed certain local codes and ordinances, especially those that may not have kept up with changing residential construction practices. We require these instructions as a minimum for a safe installation.

Wear safety glasses and work gloves. Have a fire extinguisher available during start-up and adjustment procedures and service calls.

CAUTION: Sheet metal parts may have sharp edges or burrs. Use care and wear appropriate protective clothing and gloves when handling parts. Failure to follow this caution could result in personal injury.

Recognize safety information. This is the safety-alert symbol . When you see this symbol on the unit and in instructions or manuals, be alert to the potential for personal injury.

Understand these signal words DANGER, WARNING, CAUTION, and NOTE. These words are used with the safety-alert symbol. DANGER identifies the most serious hazards which will result in severe personal injury or death. WARNING signifies hazards which could result in personal injury or death. CAUTION

This forced air furnace is equipped for use with natural gas at altitudes 0 - 10,000 ft (0 - 3,050m), except 140 size furnaces are only appro ved for altitudes 0 - 7,000 ft.

INST ALLATION

(0 - 2,135 m ). An accessory kit, supplied by the manufacturer, shall be used to convert to propane gas use or may be required for some natural gas applications. This furnace is for indoor installation in a building constructed on site. This furnace m a y be installed in a manufactured (mobile) home when stated on rating plate and using factory au thorized kit. This furnace may be installed on combustible flooring in alcove or closet at This furna ce re qu ires a spe cial ve nting s yste m . Re fer to the insta llation instru ction s for parts list and method of installation. This furnace is for use with schedule -40 PVC, PVC-DWV, CPV C, or ABS-DW V pipe, and must not be vented in common with other gas-fired appliances. Construction through which vent/air intake pipes ma y be installed is maxim um 24 inches (600 mm ), minimum 3/4 inches (19 mm) thickness (including roofing materials).

For upflow and downflow applications, furnace must be installed level, or pitched within 1/2" of level. For a horizontal application, the furnace must be pitched minimum 1/4" to m aximum of 1/2" forward for proper drainage. S ee Installation Manual for IM PO R TANT unit support details on horizontal applications.

MINIMUM INCHES CLEARANCE T O COMBUSTIBLE CONSTRUCTION

ALL POSITIONS:

Minimum front clearance for service 30 inches (762mm).

†

140 size furnaces require 1 inch back clearance to combustible materials.

DOWNFLOW POSITIONS:

†

For installation on combustible floors only when installed on special base No. KGASB0201ALL, Coil Assem bly, Part No. CD5 or CK5, or Coil Casing, Part No. KCAKC.

HORIZONTAL POSITIONS:

Line contact is permissible only between lines form ed by intersections of top and two sides of furnace jacket, and building joists, studs, or framing. Clearance shown is for air inlet an d air outlet ends.

120 and 140 size furnaces require 1 inch bottom clearance to combustible materials.

Minimum Inches Clearance To Combustible Construction

LEVEL (0")

UPFLOW OR DOWNFLOW

This furnace is approved for UPFLOW, DOW NF LOW and HORIZONTAL installations.

Clearance arrows do not change with furnace orientatio n.

†

1/2" MAX

as described below.

MIN 1/4" TO 1/2 " MAX

FRONT

TOP/PLENUM

FRONT

HORIZONTAL

MIN

328066-201 REV. A LIT -TO P

Fig. 3—Clearances to Combustibles

—2—

Clearance in inches.

BOTTOM

†

Vent clearance to combustibles 0".

A02248

⁄

A02147

⁄

19"

⁄

OUTLET

2-IN. COMBUSTION-

AIR CONN

⁄2-IN. DIA

GAS CONN

⁄8-IN. DIA

POWER CONN

⁄2-IN. DIA

THERMOSTAT ENTRY

2-IN. VENT CONN

⁄

SIDE INLET

" TYP

⁄

BOTTOM INLET

⁄

TYP

⁄

(DOWNFLOW &

OR ALTERNATE

TRAP LOCATION

OUTLET

AIRFLOW

HORIZONTAL RIGHT)

CONDENSATE DRAIN

-IN. DIA GAS CONN

⁄

TYP

⁄

TYP

⁄

TYP

⁄

TYP

⁄

CONDENSATE

INLET

(UPFLOW)

DRAIN LOCATION

DIMPLE LOCATORS

FOR HORIZONTAL

HANGING

x 12-in. rectangle.

see flex duct manufacturer’s recommendations for equivalent diameters.

a. For 800 CFM–16-in. round or 14

2. Minimum return-air opening at furnace:

-in. rectangle.

x 19

x 23

literature for specific use of single side inlets. The use of both side inlets, a

combination of 1 side and the bottom, or the bottom only will ensure adequate

c. For 1600 CFM–22-in. round or 14

d. For airflow requirements above 1800 CFM, see Air Delivery table in Product Data

b. For 1200 CFM–20-in. round or 14

DIMENSIONS (IN.)

Fig. 2—Dimensional Drawing

return air openings for airflow requirements above 1800 CFM at 0.5” W.C. ESP.

(ALTERNATE

UPFLOW)

SIDE INLET

⁄

TYP

⁄

TYP

CONDENSATE

⁄

DRAIN LOCATION

(UPFLOW)

" TYP

⁄

SIDE INLET

NOTES: 1. Minimum return-air openings at furnace, based on metal duct. If flex duct is used,

024040 17-1/2 15-7/8 16

036040 17-1/2 15-7/8 16

024060 17-1/2 15-7/8 16

036060 17-1/2 15-7/8 16

048060 17-1/2 15-7/8 16

036080 17-1/2 15-7/8 16

048080 17-1/2 15-7/8 16

060080 21 19-3/8 19-1/2

048100 21 19-3/8 19-1/2

060100 21 19-3/8 19-1/2

UNIT SIZE A D E

060120 24-1/2 22-7/8 23

⁄8-IN. DIA

POWER CONN

CONDENSATE

DRAIN TRAP

CONDENSATE DRAIN

TRAP LOCATION

(DOWNFLOW &

HORIZONTAL LEFT)

⁄

⁄2-IN. DIA

2-IN. COMBUSTION-

AIR CONN

GAS CONN

2-IN. VENT CONN

⁄8-IN. DIA

ACCESSORY

ENTRY

⁄

⁄2-IN. DIA THERMOSTAT

LOCATION

POWER ENTRY

—3—

is used to identify unsafe practices which would result in minor personal injury or product and property damage. NOTE is used to highlight suggestions which will result in enhanced installation, reliability, or operation.

The 345MAV Multipoise Condensing Gas-Fired Furnaces are CSA (formerly AGA and CGA) design-certified for natural and propane gases (see furnace rating plate) and for installation in alcoves, attics, basements, closets, utility rooms, crawlspaces, and garages. The furnace is factory-shipped for use with natural gas. A CSA (formerly AGA and CGA) listed gas conversion kit is required to convert furnace for use with propane gas.

See Fig. 3 for required clearances to combustibles. Maintain a 1-in. clearance from combustible materials to supply air

ductwork for a distance of 36 inches horizontally from the furnace. See NFPA 90B or local code for further requirements.

These furnaces SHALL NOT be installed directly on carpeting, tile, or any other combustible material other than wood flooring. In downflow installations, factory accessory floor base MUST be used when installed on combustible materials and wood flooring. Special base is not required when this furnace is installed on manufacturer’s Coil Assembly Part No. CD5 or CK5, or when Coil Box Part No. KCAKC is used.

The design of this furnace is NOT CSA (formerly AGA and CGA) design-certified for installation in recreation vehicles or outdoors.

This furnace is designed for continuous return-air minimum temperature of 60°F db or intermittent operation down to 55°F db such as when used with a night setback thermostat. Return-air temperature must not exceed 85°F db. Failure to follow these return-air limits may affect reliability of heat exchangers, motors, and controls. (See Fig. 4.)

These furnaces are shipped with the drain and pressure tubes connected for UPFLOW applications. Minor modifications are required when used in DOWNFLOW, HORIZONTAL RIGHT, or HORIZONTAL LEFT (supply-air discharge direction) applications as shown in Fig. 1. See details in Applications section.

These furnaces are shipped with the following materials to assist in proper furnace installation. These materials are shipped in the main blower compartment.

A94163

Fig. 4—Return-Air Temperature

Installer Packet includes:

Installation, Startup, and Operating Instructions Service and Maintenance Instructions User’s Information Manual Warranty Certificate

Loose Parts Bag includes: Quantity

Pressure tube extension 1 Collector Box or condensate trap extension tube 1 Inducer housing drain tube 1 1/2-in CPVC street elbow 2 Drain tube coupling 1 Drain tube coupling grommet 1 Vent and combustion-air pipe support 2 Condensate trap hole filler plug 3 Vent and combustion-air intake hole filler plug 2 Combustion-air pipe perforated disk assembly 1

Vent Pipe Extension 1*

* ONLY supplied with some furnaces.

CODES AND STANDARDS

Follow all national and local codes and standards in addition to these instructions. The installation must comply with regulations

of the serving gas supplier, local building, heating, plumbing, and other codes. In absence of local codes, the installation must comply with the national codes listed below and all authorities having jurisdiction.

In the United States and Canada, follow all codes and standards for the following:

I. SAFETY

• US: National Fuel Gas Code (NFGC) NFPA 54-2002/ANSI Z223.1-2002 and the Installation Standards, Warm Air Heating and Air Conditioning Systems ANSI/NFPA 90B

• CANADA: National Standard of Canada, Natural Gas and Propane Installation Code (NSCNGPIC) CSA B149.1-00.

II. GENERAL INSTALLATION

• US: NFGC and the NFPA 90B. For copies, contact the National Fire Protection Association Inc., Batterymarch Park, Quincy, MA 02269; or for only the NFGC contact the American Gas Association, 400 N. Capitol, N.W., Washington DC 20001

• CANADA: NSCNGPIC. For a copy, contact Standard Sales, CSA International, 178 Rexdale Boulevard, Etobicoke (Toronto), Ontario, M9W 1R3, Canada.

III. COMBUSTION AND VENTILATION AIR

• US: Section 5.3 of the NFGC, Air for Combustion and Ventilation

• CANADA: Part 7 of the NSCNGPIC, Venting Systems and Air Supply for Appliances

IV. DUCT SYSTEMS

• US and CANADA: Air Conditioning Contractors Association (ACCA) Manual D, Sheet Metal and Air Conditioning Contractors National Association (SMACNA), or American Society of Heating, Refrigeration, and Air Conditioning Engineers (ASHRAE) 2001 Fundamentals Handbook Chapter 34.

V. ACOUSTICAL LINING AND FIBROUS GLASS DUCT

• US and CANADA: current edition of SMACNA, NFPA 90B as tested by UL Standard 181 for Class I Rigid Air Ducts

VI. GAS PIPING AND GAS PIPE PRESSURE TESTING

• US: NFGC; chapters 2, 3, 4, and 9 and national plumbing codes

• CANADA: NSCNGPIC Parts 3, 4, 5, A, B, E, and H.

VII. ELECTRICAL CONNECTIONS

• US: National Electrical Code (NEC) ANSI/NFPA 70-2002

• CANADA: Canadian Electrical Code CSA C22.1

—4—

BLOWER SHELF

CONDENSATE TRAP (INSIDE)

ALTERNATE DRAIN TUBE LOCATION

CONDENSATE TRAP

DRAIN TUBE LOCATION

UPFLOW APPLICATIONS

FURNACE DOOR

FIELD

DRAIN

CONN

EXTERNAL UPFLOW APPLICATIONS

SLOT FOR SCREW

HORIZONTAL

APPLICATION

(OPTIONAL)

WIRE TIE GUIDES (WHEN USED)

CONDENSATE TRAP

FURNACE

SIDE

FURNACE DOOR

FIELD

DRAIN

CONN

FURNACE SIDE

SIDE VIEW FRONT VIEW END VIEW FRONT VIEW

DOWNFLOW AND ALTERNATE

⁄4 OD COLLECTOR BOX TO TRAP RELIEF PORT

⁄2 OD INDUCER HOUSING DRAIN CONNECTION

⁄8 OD COLLECTOR BOX DRAIN CONNECTION

SCREW HOLE FOR UPFLOW OR DOWNFLOW APPLICATIONS (OPTIONAL)

⁄2-IN. PVC OR CPVC

HORIZONTAL

APPLICATIONS

FRONT VIEW SIDE VIEW

Fig. 5—Condensate Trap

ELECTROSTATIC DISCHARGE (ESD) PRECAUTIONS

CAUTION: Electrostatic discharge can affect electronic

components. Take precautions during furnace installation and servicing to protect the furnace electronic control. Precautions will prevent electrostatic discharges from personnel and hand tools which are held during the procedure. These precautions will help to avoid exposing the control to electrostatic discharge by putting the furnace, the control, and the person at the same electrostatic potential.

1. Disconnect all power to the furnace. Multiple disconnects may be required. DO NOT TOUCH THE CONTROL OR ANY WIRE CONNECTED TO THE CONTROL PRIOR TO DISCHARGING YOUR BODY’S ELECTROSTATIC CHARGE TO GROUND.

2. Firmly touch a clean, unpainted, metal surface of the furnace chassis which is close to the control. Tools held in a person’s hand during grounding will be satisfactorily discharged.

3. After touching the chassis, you may proceed to service the control or connecting wires as long as you do nothing that recharges your body with static electricity (for example; DO NOT move or shuffle your feet, DO NOT touch ungrounded objects, etc.).

4. If you touch ungrounded objects (recharge your body with static electricity), firmly touch metal surface again before touching control or wires.

A93026

5. Use this procedure for installed and uninstalled (ungrounded) furnaces.

6. Before removing a new control from its container, discharge your body’s electrostatic charge to ground to protect the control from damage. If the control is to be installed in a furnace, follow items 1 through 5 before bringing the control or yourself into contact with the furnace. Put all used AND new controls into containers before touching ungrounded objects.

7. An ESD service kit (available from commercial sources) may also be used to prevent ESD damage.

INTRODUCTION

The model 345MAV 4-way multipoise, Gas-Fired, Category IV, condensing furnaces are available in model sizes ranging in gas input rates of 40,000 to 120,000 Btuh. For accessory installation details, refer to applicable installation literature.

APPLICATIONS

CAUTION: Local codes may require a drain pan under

entire furnace and condensate trap when a condensing furnace is used in an attic application or over a finished ceiling. Failure to follow this caution will result in minor property damage.

I. GENERAL

Some assembly and modifications are required for furnaces installed in any of the 4 applications shown in Fig. 1. All drain and pressure tubes are connected as shown in Fig. 6. See appropriate application instructions for these procedures.

—5—

PLUG

CAP

COLLECTOR BOX

DRAIN TUBE (BLUE

& WHITE STRIPED)

COLLECTOR BOX

TUBE (PINK)

PLUG

CAP

COLLECTOR BOX

DRAIN TUBE (BLUE

& WHITE STRIPED)

COLLECTOR BOX

TUBE (PINK)

COLLECTOR BOX

TUBE (GREEN)

INDUCER HOUSING

(MOLDED) DRAIN

TUBE (BEHIND

COLLECTOR BOX

DRAIN TUBE)

COLLECTOR BOX

DRAIN TUBE (BLUE)

FIELD-INSTALLED

FACTORY-SUPPLIED

DRAIN TUBE

COUPLING (LEFT

DRAIN OPTION)

FIELD-INSTALLED

FACTORY-SUPPLIED

DRAIN TUBE

FIELD-INSTALLED

FACTORY-SUPPLIED

⁄2-IN. CPVC STREET

ELBOWS (2) FOR

LEFT DRAIN OPTION

FIELD-INSTALLED

FACTORY-SUPPLIED

COUPLING (RIGHT

CONDENSATE TRAP

DRAIN TUBE

DRAIN OPTION)

A94163

Fig. 6—Factory-Shipped Upflow Tube Configuration

(Shown With Blower Access Panel Removed)

II. UPFLOW APPLICATIONS

An upflow furnace application is where furnace blower is located below combustion and controls section of furnace, and conditioned air is discharged upwards.

A. Condensate Trap Location (Factory-Shipped Orientation)

The condensate trap is factory installed in the blower shelf and factory connected for UPFLOW applications. A factory-supplied tube is used to extend the condensate trap drain connection to the desired furnace side for field drain attachment. See Condensate Trap Tubing (Factory-Shipped Orientation) section for drain tube extension details. (See Fig. 6.)

B. Condensate Trap Tubing (Factory-Shipped Orientation)

NOTE: See Fig. 6 or tube routing label on main furnace door to

confirm location of these tubes.

1. Collector Box Drain, Inducer Housing Drain, Relief Port, and Pressure Switch Tubes

These tubes are factory attached to the condensate trap and pressure switch ready for use in UPFLOW applications. These tubes can be identified by their connection location and also by a color label on each tube. These tubes are identified as follows: collector box drain tube (blue label), inducer housing drain tube (violet label or molded), relief port tube (green label), and pressure switch tube (pink label).

COLLECTOR BOX

TUBE (GREEN)

COLLECTOR BOX

DRAIN TUBE (BLUE)

CONDENSATE

TRAP

INDUCER HOUSING

DRAIN TUBE

(VIOLET)

A94164

Fig. 7—Alternate Upflow Tube Configuration and

Trap Location

2. Condensate Trap Drain Tube The condensate trap drain connection must be extended for

field attachment by doing the following: a. Determine location of field drain connection. (See Fig. 2

or 6.)

NOTE: If internal filter is used, drain tube should be located to opposite side of casing from return duct attachment to assist in filter removal.

b. Remove and discard casing drain hole plug button from

desired side.

c. Install drain tube coupling grommet (factory-supplied in

loose parts bag) in selected casing hole.

d. Slide drain tube coupling (factory-supplied in loose parts

bag) through grommet ensuring long end of coupling faces blower.

e. Cement 2 factory-supplied 1/2-in. street CPVC elbows to

the rigid drain tube connection on the condensate trap. (See Fig. 6.) These elbows must be cemented together and cemented to condensate trap drain connection.

NOTE: Failure to use CPVC elbows may allow drain to kink and prevent draining.

f. Connect larger diameter drain tube and clamp (factory-

supplied in loose parts bag) to condensate trap and clamp

securely. g. Route tube to coupling and cut to appropriate length. h. Attach tube to coupling and clamp securely.

—6—

C. Condensate Trap Location (Alternate Upflow Orientation)

An alternate location for the condensate trap is the left-hand side of casing. (See Fig. 2 and 7.)

NOTE: If the alternate left-hand side of casing location is used, the factory-connected drain and relief port tubes must be disconnected and modified for attachment. See Condensate Trap Tubing (Alternate Upflow Orientation) section for tubing attachment.

To relocate condensate trap to the left-hand side, perform the following:

1. Remove 3 tubes connected to condensate trap.

2. Remove trap from blower shelf by gently pushing tabs inward and rotating trap.

3. Install casing hole filler cap (factory-supplied in loose parts bag) into blower shelf hole where trap was removed.

WARNING: Casing hole filler cap must be installed in blower shelf hole when condensate trap is relocated. Failure to follow this warning could result in electrical shock, fire, personal injury or death.

4. Install condensate trap into left-hand side casing hole by inserting tube connection stubs through casing hole and rotating until tabs snap into locking position.

5. Fill unused condensate trap casing holes with plastic filler caps (factory-supplied in loose parts bag).

D. Condensate Trap Tubing (Alternate Upflow Orientation)

NOTE: See Fig. 7 or tube routing label on main furnace door to

confirm location of these tubes.

1. Collector Box Drain Tube Connect collector box drain tube (blue label) to condensate

trap.

NOTE: On 17-1/2-in. wide furnaces ONLY, cut tube between corrugated sections to prevent kinks from occurring.

2. Inducer Housing Drain Tube a. Remove and discard LOWER (molded) inducer housing

drain tube which was previously connected to condensate trap.

b. Use inducer housing drain extension tube (violet label

and factory-supplied in loose parts bag) to connect LOWER inducer housing drain connection to the con-

densate trap. c. Determine appropriate length, cut, and connect tube. d. Clamp tube to prevent any condensate leakage.

3. Relief Port Tube a. Connect relief port tube (green label) to condensate trap.

b. Use smaller diameter tube (factory-supplied in loose

parts bag) to extend this tube if required.

c. Determine appropriate length, cut, and connect tube.

E. Condensate Trap Field Drain Attachment

Refer to Condensate Drain section for recommendations and procedures.

F. Pressure Switch Tubing

The LOWER collector box pressure tube (pink label) is factory connected to the pressure switch and should not require any modification.

NOTE: See Fig. 6 or 7 or tube routing label on main furnace door to check for proper connections.

G. Upper Collector Box and Inducer Housing (Unused) Drain Connections

UPPER COLLECTOR BOX DRAIN CONNECTION

Attached to the UPPER collector box drain connection is a factory-installed corrugated, plugged tube (blue and white striped label). This tube is plugged to prevent condensate leakage in this application. Ensure this tube is plugged.

NOTE: See Fig. 6 or 7 or tube routing label on main furnace door to check for proper connections.

UPPER INDUCER HOUSING DRAIN CONNECTION

Attached to the UPPER (unused) inducer housing drain connection is a cap and clamp. This cap is used to prevent condensate leakage in this application. Ensure this connection is capped.

NOTE: See Fig. 6 or 7 or tube routing label on main furnace door to check for proper connections.

H. Condensate Trap Freeze Protection

Refer to Condensate Drain Protection section for recommendations and procedures.

III. DOWNFLOW APPLICATIONS

A downflow furnace application is where furnace blower is located above combustion and controls section of furnace, and conditioned air is discharged downwards.

A. Condensate Trap Location

The condensate trap must be removed from the factory-installed blower shelf location and relocated in selected application location as shown in Fig. 2, 8, or 9.

To relocate condensate trap from the blower shelf to desired location, perform the following:

1. Remove 3 tubes connected to condensate trap.

2. Remove trap from blower shelf by gently pushing tabs inward and rotating trap.

3. Install casing hole filler cap (factory-supplied in loose parts bag) into blower shelf hole where trap was removed.

4. Install condensate trap into left-hand side casing hole by inserting tube connection stubs through casing hole and rotating until tabs snap into locking position.

5. Fill unused condensate trap casing holes with plastic filler caps (factory-supplied in loose parts bag).

B. Condensate Trap Tubing NOTE: See Fig. 8 or 9 or tube routing label on main furnace door

to check for proper connections.

1. Collector Box Drain Tube a. Remove factory-installed plug from LOWER collector

box drain tube (blue and white striped label).

b. Install removed clamp and plug into UPPER collector

box drain tube (blue label) which was connected to condensate trap.

c. Connect LOWER collector box drain connection to

condensate trap. (1.) Condensate Trap Located on Left Side of Casing

(a.) Connect LOWER collector box drain tube

(blue and white striped label) to condensate trap. Tube does not need to be cut.

—7—

COLLECTOR BOX

DRAIN TUBE (BLUE)

CAP

PLUG

COLLECTOR BOX

TUBE (GREEN)

COLLECTOR BOX

EXTENSION TUBE

COLLECTOR BOX

TUBE (PINK)

COLLECTOR BOX

DRAIN TUBE (BLUE

& WHITE STRIPED)

COLLECTOR BOX EXTENSION TUBE

CONDENSATE

TRAP

INDUCER HOUSING

DRAIN TUBE (VIOLET)

PLUG CAP

COLLECTOR BOX DRAIN TUBE (BLUE)

COLLECTOR BOX TUBE (PINK)

COLLECTOR BOX TUBE (GREEN)

COLLECTOR BOX EXTENSION TUBE

COLLECTOR BOX DRAIN TUBE (BLUE & WHITE STRIPED)

COLLECTOR BOX EXTENSION TUBE

INDUCER HOUSING DRAIN TUBE (VIOLET)

CONDENSATE TRAP

COLLECTOR BOX EXTENSION DRAIN TUBE

DRAIN TUBE COUPLING

Fig. 8—Downflow Tube Configuration

(Left-Hand Trap Installation)

(b.) Clamp tube to prevent any condensate leakage.

(2.) Condensate Trap Located on Right Side of Casing

(a.) Install drain tube coupling (factory-supplied in

loose parts bag) into collector box drain tube (blue and white striped label) which was previously plugged.

(b.) Connect larger diameter drain tube (factory-

supplied in loose parts bag) to drain tube coupling, extending collector box drain tube for connection to condensate trap.

(c.) Route extended collector box drain tube be-

tween gas valve and inlet housing as shown in

Fig. 9. (d.) Determine appropriate length and cut. (e.) Connect to condensate trap. (f.) Clamp tube to prevent any condensate leakage.

2. Inducer Housing Drain Tube a. Remove factory-installed cap and clamp from LOWER

inducer housing drain connection.

b. Remove and discard UPPER (molded) inducer housing

drain tube which was previously connected to condensate trap.

c. Install cap and clamp on UPPER inducer housing drain

connection where molded drain tube was removed.

d. Use inducer housing drain tube (violet label and factory-

supplied in loose parts bag) to connect LOWER inducer housing drain connection to the condensate trap.

e. Connect inducer housing drain connection to condensate

trap.

A94165

A94166

Fig. 9—Downflow Tube Configuration

(Right-Hand Trap Installation)

(1.) Condensate Trap Located on Left Side of Casing

(a.) Determine appropriate length and cut. (b.) Connect tube to condensate trap. (c.) Clamp tube to prevent any condensate leakage.

(2.) Condensate Trap Located on Right Side of Casing

(a.) Route inducer housing drain tube (violet label)

between gas valve and inlet housing behind

collector box drain tube. (b.) Determine appropriate length and cut. (c.) Connect tube to condensate trap. (d.) Clamp tube to prevent any condensate leakage.

3. Relief Port Tube Refer to Pressure Switch Tubing section for connection procedure.

C. Condensate Trap Field Drain Attachment

Refer to Condensate Drain section for recommendations and procedures.

D. Pressure Switch Tubing

One collector box pressure tube (pink label) is factory connected to the pressure switch for use when furnace is installed in UPFLOW applications. This tube MUST be disconnected and used for the condensate trap relief port tube. The other collector box pressure tube (green label) which was factory connected to the condensate trap relief port connection MUST be connected to the pressure switch in DOWNFLOW or HORIZONTAL RIGHT applications. NOTE: See Fig. 8 or 9 or tube routing label on main furnace door to check for proper connections. Relocate tubes as described below.

1. Disconnect collector box pressure tube (pink label) attached to pressure switch.

—8—

2. Use smaller diameter tube (factory-supplied in loose parts bag) to extend collector box pressure tube (green label) which was previously connected to condensate trap relief port connection.

3. Connect collector box pressure tube (green label) to pressure switch connection labeled "collector box."

4. Use remaining smaller diameter tube (factory-supplied in loose parts bag) to extend collector box pressure tube (pink label) which was previously connected to pressure switch.

5. Route this extended tube (pink label) to condensate trap relief port connection.

6. Determine appropriate length, cut, and connect tube.

7. Clamp tube to relief port connection.

E. Condensate Trap Freeze Protection

Refer to Condensate Drain Protection section for recommendations and procedures.

IV. HORIZONTAL LEFT (SUPPLY-AIR DISCHARGE) APPLICATIONS

A horizontal left furnace application is where furnace blower is located to the right of combustion and controls section of furnace, and conditioned air is discharged to the left.

NOTE: The auxiliary junction box (J-Box) MUST be relocated to opposite side of furnace casing. (See Fig. 10.) See Electrical Connection section for J-Box relocation.

A. Condensate Trap Location

The condensate trap must be removed from the factory-installed blower shelf location and relocated in selected application location as shown in Fig. 2 or 10.

To relocate condensate trap from the blower shelf to desired location, perform the following:

PLUG

AUXILIARY "J" BOX

1. Remove 3 tubes connected to condensate trap.

2. Remove trap from blower shelf by gently pushing tabs inward and rotating trap.

3. Install casing hole filler cap (factory-supplied in loose parts bag) into blower shelf hole where trap was removed.

4. Install condensate trap into casing hole by inserting tube connection stubs through casing hole and rotating until tabs snap into locking position.

5. Fill unused condensate trap casing holes with plastic filler caps (factory-supplied in loose parts bag).

B. Condensate Trap Tubing NOTE: See Fig. 10 or tube routing label on main furnace door to

check for proper connections.

1. Collector Box Drain Tube a. Install drain tube coupling (factory-supplied in loose

parts bag) into collector box drain tube (blue label) which was previously connected to condensate trap.

b. Connect large diameter drain tube and clamp (factory-

supplied in loose parts bag) to drain tube coupling, extending collector box drain tube.

c. Route extended tube (blue label) to condensate trap and

cut to appropriate length.

d. Clamp tube to prevent any condensate leakage.

CAP

COLLECTOR BOX DRAIN TUBE (BLUE AND WHITE STRIPED)

CONDENSATE

TRAP

COLLECTOR

BOX EXTENSION

DRAIN TUBE

COLLECTOR BOX

EXTENSION TUBE

DRAIN TUBE COUPLING

COLLECTOR BOX TUBE (PINK)

RELOCATE TUBE BETWEEN BLOWER SHELF AND INDUCER HOUSING FOR

040, 060, AND 080 HEATING INPUT FURNACES

Fig. 10—Horizontal Left Tube Configuration

—9—

COLLECTOR BOX TUBE (GREEN)

INDUCER HOUSING DRAIN TUBE (VIOLET)

COLLECTOR BOX DRAIN TUBE (BLUE)

A00215

A 3-IN. MINIMUM CLEARANCE TO COMBUSTION-AIR INTAKE IS REQUIRED.

VENT

COMBUSTION–AIR

GAS VALVE

INTAKE

MANUAL

SHUTOFF

⁄

″

SEDIMENT TRAP

NOTE: LOCAL CODES MAY REQUIRE A DRAIN PAN UNDER THE

FURNACE AND CONDENSATE TRAP WHEN A CONDENSING FURNACE IS INSTALLED ABOVE FINISHED CEILINGS.

CONDENSATE TRAP

Fig. 11—Attic Location and Working Platform

2. Inducer Housing Drain Tube a. Remove and discard LOWER (molded) inducer housing

drain tube which was previously connected to condensate trap.

b. Use inducer housing drain extension tube (violet label

and factory-supplied in loose parts bag) to connect LOWER inducer housing drain connection to the con-

densate trap. c. Determine appropriate length, cut, and connect tube. d. Clamp tube to prevent any condensate leakage.

3. Relief Port Tube a. Use smaller diameter tube (factory-supplied in loose

parts bag) to extend collector box tube (green label) which was previously connected to the condensate trap.

b. Route extended collector box pressure tube to relief port

connection on the condensate trap. c. Determine appropriate length, cut, and connect tube. d. Clamp tube to prevent any condensate leakage.

C. Condensate Trap Field Drain Attachment

Refer to Condensate Drain section for recommendations and procedures.

D. Pressure Switch Tubing

The LOWER collector box pressure tube (pink label) is factory connected to the pressure switch for use when furnace is installed in UPFLOW applications. This tube MUST be disconnected, extended, rerouted, and then reconnected to the pressure switch in HORIZONTAL LEFT applications.

NOTE: See Fig. 10 or tube routing label on main furnace door to check for proper connections.

A 12-IN. MIN HORIZONTAL PIPE SECTION IS RECOMMENDED WITH SHORT (5 TO 8 FT) VENT SYSTEMS TO REDUCE EXCESSIVE CONDENSATE DROPLETS FROM

30-IN. MIN WORK AREA

DRAIN

EXITING THE VENT PIPE.

ACCESS OPENING FOR TRAP

A96184

Modify tube as described below.

1. Disconnect collector box pressure tube (pink label) attached to pressure switch.

2. Use smaller diameter tube (factory-supplied in loose parts bag) to extend tube disconnected in item 1.

3. Route extended tube: a. Behind inducer housing.

b. Between blower shelf and inducer housing. c. Behind inducer motor bracket. d. Between inducer motor and pressure switch.

4. Determine appropriate length, cut, and reconnect tube to pressure switch connection labeled COLLECTOR BOX.

E. Condensate Trap Freeze Protection

Refer to Condensate Drain Protection section for recommendations and procedures.

F. Construct a Working Platform

Construct working platform where all required furnace clearances are met. (See Fig. 3 and 11.)

CAUTION: The condensate trap MUST be installed below furnace. See Fig. 5 for dimensions. The drain connection to condensate trap must also be properly sloped to an open drain. Failure to follow this caution will result in intermittent unit operation.

NOTE: Vent pipe length is restricted to a minimum of 5 ft. (See Table 6.)

—10—

CAP

PLUG

COLLECTOR BOX DRAIN TUBE

(BLUE AND WHITE STRIPED)

INDUCER HOUSING

DRAIN TUBE (VIOLET)

COLLECTOR BOX

EXTENSION TUBE

Fig. 12—Horizontal Right Tube Configuration

COLLECTOR BOX DRAIN TUBE (BLUE)

COLLECTOR BOX TUBE (GREEN)

COLLECTOR BOX EXTENSION TUBE

COLLECTOR BOX TUBE (PINK)

AUXILARY “J” BOX RELOCATED HERE

CONDENSATE TRAP

A00214

NOTE: A 12-in. minimum horizontal pipe section is recommended with short (5 to 8 ft) vent systems. This recommendation is to reduce excessive condensate droplets from exiting the vent pipe. (See Fig. 11 or 38.)

V. HORIZONTAL RIGHT (SUPPLY-AIR DISCHARGE) APPLICATIONS

A horizontal right furnace application is where furnace blower is located to the left of combustion and controls section of furnace, and conditioned air is discharged to the right.

CAUTION: Local codes may require a drain pan under entire furnace and condensate trap when a condensing furnace is used in attic application or over a finished ceiling. Failure to follow this caution will result in minor property damage.

NOTE: In Canada, installations shall be in accordance with current NSCNGPIC Installation Codes and/or local codes.

A. Condensate Trap Location

The condensate trap must be removed from the factory-installed blower shelf location and relocated in selected application location as shown in Fig. 2 or 12.

To relocate condensate trap from the blower shelf to desired location, perform the following:

1. Remove 3 tubes connected to condensate trap.

2. Remove trap from blower shelf by gently pushing tabs inward and rotating trap.

3. Install casing hole filler cap (factory-supplied in loose parts bag) into blower shelf hole where trap was removed.

4. Install condensate trap into left-hand side casing hole by inserting tube connection stubs through casing hole and rotating until tabs snap into locking position.

5. Fill unused condensate trap casing holes with plastic filler caps (factory-supplied in loose parts bag).

B. Condensate Trap Tubing NOTE: See Fig. 12 or tube routing label on main furnace door to

check for proper connections.

1. Collector Box Drain Tube a. Remove factory-installed plug from LOWER collector

box drain tube (blue and white striped label).

b. Install removed clamp and plug into UPPER collector

box drain tube (blue label) which was previously connected to condensate trap.

c. Connect LOWER collector box drain tube (blue and

white striped label) to condensate trap. Tube does not need to be cut.

d. Clamp tube to prevent any condensate leakage.

2. Inducer Housing Drain Tube a. Remove factory-installed cap and clamp from LOWER

inducer housing drain connection.

—11—

b. Remove and discard UPPER (molded) inducer housing

drain tube which was previously connected to condensate trap.

c. Install cap and clamp on UPPER inducer housing drain

connection where molded drain tube was removed.

d. Use inducer housing drain extension tube (violet label

and factory-supplied in loose parts bag) to connect LOWER inducer housing drain connection to condensate trap.

e. Determine appropriate length, cut, and connect tube to

condensate trap.

f. Clamp tube to prevent any condensate leakage.

3. Relief Port Tube Refer to Pressure Switch Tubing section for connection

procedure.

C. Condensate Trap Field Drain Attachment

Refer to Condensate Drain section for recommendations and procedures.

D. Pressure Switch Tubing

NOTE: See Fig. 12 or tube routing label on main furnace door to check for proper connections.

Relocate tubes as described below.

1. Disconnect collector box pressure tube (pink label) attached to pressure switch.

2. Use smaller diameter tube (factory-supplied in loose parts bag) to extend collector box pressure tube (green label) which was previously connected to condensate trap relief port connection.

3. Route extended collector box pressure tube behind inducer motor bracket then between inducer motor and pressure switch.

4. Connect collector box pressure tube (green label) to pressure switch connection labeled COLLECTOR BOX.

5. Use remaining smaller diameter tube (factory-supplied in loose parts bag) to extend collector box pressure tube (pink label) which was previously connected to pressure switch.

6. Route this extended tube (pink label) to condensate trap relief port connection.

7. Determine appropriate length, cut, and connect tube.

8. Clamp tube to relief port connection.

E. Condensate Trap Freeze Protection

Refer to Condensate Drain Protection section for recommendations and procedures.

F. Construct a Working Platform

Construct working platform where all required furnace clearances are met. (See Fig. 3 and 11.)

NOTE: Vent pipe length is restricted to a minimum of 5 ft. (See Table 6.)

LOCATION

I. GENERAL

This furnace must:

• be provided with air for combustion, ventilation, and dilution of flue gases in accordance with the NFGC or NSCNGPIC. The furnace MUST NOT be located in a confined space without special provisions for dilution or ventilation air. See AIR FOR COMBUSTION AND VENTILATION section.

• be installed so the electrical components are protected from water.

• not be installed directly on any combustible material other than wood flooring (refer to SAFETY CONSIDERATIONS).

• be located so combustion-air and vent pipe maximum lengths are not exceeded. Refer to Table 6.

• be located where available electric power and gas supplies meet specifications on the furnace rating plate.

• be attached to an air distribution system and be located as close to the center of the distribution system as possible. Refer to Air Ducts section.

FRONT

B A C K

BACK

→

LEVEL (0″)

⁄2″ MAX

UPFLOW OR DOWNFLOW HORIZONTAL

FRONT

MIN

⁄2″ MAX

⁄4″

FRONT

Fig. 13—Proper Condensate Drainage

A02146

FRONT

A93043

Fig. 14—Prohibit Installation on Back

WARNING: Do not install furnace on its back. Safety

control operation will be adversely affected. Never connect return-air ducts to back of furnace. Failure to follow this warning could result in fire, personal injury, or death. (See Fig. 14.)

—12—

• be provided with ample space for servicing and cleaning. Always comply with minimum fire protection clearances shown on the furnace clearance-to-combustibles label.

NOTE: For upflow/downflow applications install furnace so that it is level or pitched forward within 1/2-in. for proper furnace operation. For horizontal applications pitch 1/4-in. minimum to 1/2-in. maximum forward to ensure proper condensate drainage from secondary heat exchangers. (See Fig. 13.)

When a furnace is installed so that supply ducts carry air circulated by the furnace to areas outside the space containing the furnace, the return air shall also be handled by duct(s) sealed to furnace casing and terminating outside the space containing the furnace to

32°F MINIMUM INSTALLED AMBIENT OR FREEZE PROTECTION REQUIRED

ensure there will not be a negative pressure condition within equipment room or space.

Fig. 15—Freeze Protection

CAUTION: This gas furnace may be used for construction heat provided that:

-The furnace is permanently installed with all electrical wiring, piping, venting and ducting installed according to these installation instructions. A return air duct is provided, sealed to the furnace casing, and terminated outside the space containing the furnace. This prevents a negative pressure condition as created by the circulating air blower, causing a flame rollout and/or drawing combustion products into the structure.

-The furnace is controlled by a thermostat. It may not be ″hot wired″ to provide heat continuously to the structure without thermostatic control.

-Clean outside air is provided for combustion. This is to minimize the corrosive effects of adhesives, sealers and other construction materials. It also prevents the entrainment of drywall dust into combustion air, which can cause fouling and plugging of furnace components.

-The temperature of the return air to the furnace is no less than 55°F, with no evening setback or shutdown. The use of the furnace while the structure is under construction is deemed to be intermittent operation per our installation instructions.

-The air temperature rise is within the rated rise range on the furnace rating plate, and the firing rate has been set to the nameplate value.

-The filters used to clean the circulating air during the construction process must be either changed or thoroughly cleaned prior to occupancy.

-The furnace, ductwork and filters are cleaned as necessary to remove drywall dust and construction debris from all HVAC system components after construction is completed.

A93058

CAUTION: Do not install furnace in a corrosive or contaminated atmosphere. Make sure all combustion and circulating air requirements are met. Failure to follow this caution will result in intermittent unit operation or performance satisfaction.

CAUTION: If these furnaces are installed in an unconditioned space where ambient temperatures may be 32°F or lower, freeze protection measures must be taken. (See Fig. 15.) Failure to follow this caution will result in minor property damage.

II. FURNACE LOCATION RELATIVE TO COOLING EQUIPMENT

The cooling coil must be installed parallel with or on downstream side of furnace to avoid condensation in heat exchanger. When installed parallel with a furnace, dampers or other means used to control flow of air shall be adequate to prevent chilled air from entering furnace. If dampers are manually operated, they must be equipped with a means to prevent operation of either unit unless damper is in full-heat or full-cool position.

III. HAZARDOUS LOCATIONS

WARNING: When the furnace is installed in a residen-

tial garage, it must be installed so that burners and ignition sources are located a minimum of 18 in. above floor. The furnace must be located or protected to avoid physical damage by vehicles. When furnace is installed in a public garage, airplane hangar, or other building having a hazardous atmosphere, unit must be installed in accordance with requirements of National Fire Protection Association, Inc. (See Fig. 16.)

AIR FOR COMBUSTION AND VENTILATION

I. GENERAL

Provisions for adequate combustion and ventilation air must be provided in accordance with Section 5.3, Air for Combustion and Ventilation, of the NFGC or applicable provisions of the local building codes.

Canadian installations must be in accordance with Section 7.2 of the Air Supply Determination for Central Heating Furnaces, Boilers, and Hot Water Heaters, and 7.3, Air Supply Openings and Ducts, of the NSCNGPIC and all authorities having jurisdiction.

—13—

18-IN. MINIMUM

TO BURNERS

A89014

Fig. 16—Leveling Legs

CAUTION: Air for combustion must not be contami-

nated by halogen compounds, which include fluoride, chloride, bromide, and iodide. These elements are found in aerosol sprays, detergents, bleaches, cleaning solvents, salts, air fresheners, and other household products. Failure to follow this caution will result in minor unit damage.

All fuel-burning equipment must be supplied with air for combustion of the fuel. Sufficient air MUST be provided to ensure there will not be a negative pressure in the equipment room or space. In addition, a positive seal MUST be made between the furnace cabinet and the return-air duct to prevent pulling air from the burner area and draft safeguard opening into the circulating air.

CAUTION: The operation of exhaust fans, kitchen ventilation fans, clothes dryers, fireplaces, or other appliances including attic and crawlspace exhaust fans could create a negative air pressure condition at the furnace. Make-up air must be provided for these devices, in addition to that required by the furnace. Failure to follow this caution will result in intermittent unit operation or performance satisfaction.

The requirements for combustion and ventilation air depend upon whether the furnace is located in a CONFINED or UNCONFINED space.

II. UNCONFINED SPACE

An unconfined space must have at least 50 cu ft for each 1000 Btuh of total input for all the appliances (such as furnaces, clothes dryers, water heaters, etc.) in the space.

For Example:

MINIMUM FLOOR AREA FOR UNCONFINED SPACE

345MAV Furnace

Input Btuh

40,000 267 60,000 400

80,000 533 100,000 667 120,000 800

Minimum Sq Ft With

7-1/2 Ft Ceiling

If the unconfined space is of unusually tight construction, air for combustion and ventilation MUST come from either the outdoors or spaces freely communicating with the outdoors. Combustion

and ventilation openings must be sized the same as for a confined space as defined below. Return air must not be taken from the room unless an equal or greater amount of air is supplied to the room.

III. CONFINED SPACE

A confined space has a volume of less than 50 cu ft per 1000 Btuh of the total input rating for all appliances installed in that space. A confined space MUST have 2 permanent openings, 1 within 12 in. of the ceiling, and the other within 12 in. of the floor which freely communicate with an unconfined space or the outdoors. (See Fig. 17 or 18.)

NOTE: In determining the free area of an opening, the blocking effect of the louvers, grilles, and screens must be considered. If the free area of a louver or grille design is unknown, it may be assumed that wood louvers have a 20 percent free area, and metal louvers or grilles have a 60 percent free area. Screens, when used, must not be smaller than 1/4-in. mesh. Louvers and grilles must be constructed so they cannot be closed.

The size of the openings depends upon whether the air comes from outside of the structure or an unconfined space inside the structure.

A. All Air from Inside the Structure

1. Each opening MUST have at least 1 sq in. of free area per 1000 Btuh of the total input for all equipment within the confined space, but not less than 100 sq in. per opening. (See Fig. 17.) The minimum dimension of air openings shall not be less than 3 in.

For Example:

COMBUSTION AIR FROM UNCONFINED SPACE

345MAV Furnace

Input Btuh

40,000 100 60,000 100

80,000 100 100,000 100 120,000 120

Free Area per Opening

(Sq In.)

2. If the building is constructed unusually tight, in addition to the 2 permanent openings that freely communicate with an unconfined space, a permanent opening directly communicating with the outdoors should be provided. This opening shall have a minimum free area of 1 sq in. per 4000 Btuh of total input rating for all equipment in the enclosure.

3. If the furnace is installed on a raised platform to provide a return-air plenum, and return air is taken directly from the hallway or space adjacent to the furnace, all air for combustion must come from outdoors. (See Fig. 18.)

B. All Air from Outside the Structure

1. If combustion air is taken from outdoors through vertical ducts, the openings and ducts MUST have at least 1 sq in. of free area per 4000 Btuh of the total input for all equipment within the confined space. (See Fig. 18.)

For Example:

COMBUSTION AIR FROM OUTDOORS THROUGH

345MAV Furnace

Input Btuh

40,000 10.0 4 60,000 15.0 5

80,000 20.0 6 100,000 25.0 6 120,000 30.0 7

VERTICAL DUCTS

Free Area per Opening

(Sq In.)

Round Pipe

(In. Dia)

—14—

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Bryant 345MAV User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual