atwood 8940 User Manual

LITERATURE NUMBER

MPD 32046

hydro flame

8900-III Series Furnace

MODELS 8935, 8940

Technical Installation Manual

ENGLISH, FRANCAIS (et Canada) •Installation

Effective 11/27/06

THIS INSTRUCTION MANUAL IS FOR USE BY AN AUTHORIZED SERVICE

TECHNICIAN TO INSTALL AN ATWOOD

INSTALLER

: LEAVE THIS MANUAL WITH APPLIANCE.

- hydro flame

FURNACE.

CONSUMER: RETAIN THIS MANUAL FOR FURTHER REF-

ERENCE.

This furnace design has been certified for installation in recreation vehicles as a MSP Category III furnace. Follow this installation instruction to insure safe operation of the furnace. Failure to install furnace according to this installation instruction nullifies the furnace warranty.

SAFETY ALERT SYMBOLS

Safety Symbols alerting you to potential personal safety hazards. Obey all safety messages following these symbols.

 WARNING  CAUTION

avoid possible avoid possible injury or death injury and/or property damage

WARNING: If the information in this manual is not followed exactly, a fire or explosion may result causing property damage, personal injury or loss of life.

— Do not store or use gasoline or other flammable

vapors and liquids in the vicinity of this or any other appliance.

— WHAT TO DO IF YOU SMELL GAS

• Evacuate all persons from vehicle.

• Shut off gas supply at gas container or source.

• Do not touch any electrical switch, or use any phone or radio in vehicle.

• Do not start vehicle’s engine or electric generator.

• Contact nearest gas supplier or qualified Service Technician for repairs.

• If you cannot reach a gas supplier or qualified Service Technician, contact the nearest fire department.

• Do not turn on gas supply until gas leak(s) has been repaired.

— Installation and service must be performed by a

qualified Service Technician, Service Center or gas supplier.

FURNACE SPECIFICATIONS ..............................................................1

DIMENSIONS ..................................................................1

WEIGHT ........................................................................1

MINIMUM CLEARANCE TO FLOORBOARDS, WALLS,

& SIMILAR COMBUSTIBLE BUILDING MATERIALS..................................2

SAFETY INFORMATION..................................................................1-2

FURNACE INSTALLATION ..................................................................2

WALL CUTOUT HORIZONTAL & VERTICAL ..............................................2-3

DUCTING HORIZONTAL & VERTICAL........................................................3

Flexible Ducting......................................................................3

Hard Ducting ........................................................................3

OPTIONAL INSTALLATION - BOTTOM DISCHARGE KIT..................................3

GAS CONNECTION ........................................................................3

ELECTRICAL CONNECTIONS ..........................................................3-4

Conductor Sizing Table ............................................................3

12 volt DC Models................................................................3-4

120 volt AC Models ................................................................4

Thermostat ..........................................................................4

DOOR INSTALLATION HORIZONTAL & VERTICAL ..........................................4

RAIN SHIELD INSTALLATION ............................................................4

DRAFT CAP ASSEMBLY ..................................................................4

CONVERTIBLE GAS CONTROL ........................................................4-5

Valve Conversion ....................................................................4

Orifice Replacement ................................................................5

SYSTEM CHECK TESTS ....................................................................5

PROPANE GAS PRESSURE ..............................................................5

STATIC PRESSURE ........................................................................5

AC & DC WIRING DIAGRAMS ............................................................5

ILLUSTRATIONS ............................................................................6

REPLACEMENT PARTS LIST & DRAWING ..............................................7

SPECIFICATIONS *(W.C. = Water Column)

MODEL # 8935 8940 8935 8940

BTU Input 35,000 40,000 35,000 40,000 Output BTU/HR 27,300 31,200 27,300 31,200 Type Gas LP LP LP/NAT LP/NAT Duct Static Pressure - .10˝ W.C.* .10˝ W.C. .10˝ W.C. .10˝ W.C. Power Supply ( Watts 132 132 360 360 Amperage 11 11 3 3

MINIMUM RETURN AIR 80 in

VOLTS) 12-DC 12-DC 120-AC 120-AC

DIMENSIONS

ALL MODELS WITH DOOR WIDTH HEIGHT DEPTH

Casing 16-1/2˝ 9-1/8˝ 23-1/2˝ FURNACE 38 lbs. Door 19-1/4˝ 9-1/4˝ 1/4˝ SHIPPING 45 lbs. Recess Bezel 20-9/16˝ 11-1/2˝

INDEX

DCLP-III DCLP-III ACLC-III ACLC-III

80 in

WEIGHT

FLOORBOARDS, WALLS & SIMILAR COMBUSTIBLE BUILDING MATERIALS*

MUST BE PROVIDED THE FULL LENGTH AND WIDTH OF UNIT

HORIZONTAL TOP VERTICAL TOP ----1/2˝ BOTTOM ------0˝ SIDES ----1˝ REAR----1/2˝

MINIMUM CLEARANCE TO

----1/2˝ BOTTOM --3/16˝ SIDES ----1˝ REAR----1/2˝

Spacing of 1/4˝ to ducting within 3 feet of furnace must be provided unless UL listed wire bound vinyl ducts are used. All ducting material should be rated for continuous use at 200˚F.

NOTE: Clearances are specifically for plywood or similar building materi-

als surrounding furnace (i.e. furnace should NOT be located under furniture or in a closet space where clothing or other material could be located.)

NOTE: Efficiency rating is a thermal rating determined under continuous

operating conditions, independent of any installation. Efficiency rate is given at 77% minimum, actual efficiency rating may be higher.

 WARNING

CARBON MONOXIDE POISONING

• Furnace must be installed and vented to these instructions.

• Improper installation, adjustment, alteration, service or mainte-

nance can cause injury or property damage.

• Improper installation location may cause furnace to produce neg-

ative pressure, affecting combustion air or venting of other appliances.

USA AND CANADA - FOLLOW ALL APPLICABLE STATE AND LOCAL CODES - IN THE ABSENCE OF LOCAL CODES OR REGULATIONS, REFER TO CURRENT STANDARDS OF:

• Recreation Vehicles ANSI A119.2/NFPA 501C.

• National Fuel Gas Code ANSI Z223.1 and/or CAN/CGA B149

Installation Codes

• Federal Mobile Home Construction & Safety Standard, Title 24 CFR,

part 3280, or when this Standard is not applicable, the Standard for Manufactured Home Installations (Manufactured Home Sites, Communities and Set-Ups), ANSI A255.1 and/or CAN/CSA-Z240 MH Series, Mobile Homes.

• Ground - National Electrical Code ANSI/NFPA No. 70 and/or CSA C22.1

• Park Trailers ANSI 119.5

NOTE: The direct high voltage spark ignition generates a radio frequency

that could cause interference with other microprocessor based equipment. Locate equipment at least five feet (5’) from furnace location. If this distance cannot be maintained, purchase MPD 37773 (a shielded high voltage lead).

 WARNING

CARBON MONOXIDE POISONING

• Properly seal door, adjust draft cap to prevent carbon monoxide

from entering coach.

• DO NOT draw combustion air from living area. DO NOT vent exhaust

air into the living area or an enclosed porch.

 CRITICAL INSTALLATION WARNINGS

• DO NOT install furnace on material that restricts return air, like carpet or any soft material such as vinyl.

• DO NOT install furnace where clearance to combustibles cannot be maintained.

DO NOT modify furnace in any way.

•

• DO NOT alter furnace for a positive grounding system.

DO NOT HI-POT furnace unless electronic ignition system (circuit

• board) has been disconnected.

DO NOT use battery charger to supply power to DC model furnace

• even when testing.

• DO NOT use 120 volt AC current with DC models.

• DO NOT use furnace cabinet area as a storage compartment.

• DO NOT vent furnace with venting system serving another appliance.

DO NOT vent furnace to an outside enclosed porch area.

•

• DO NOT use for temporary heating of buildings or structures under construction.

• Protect building materials from degrading from flue gas exhaust.

• Protect furnace electrical components from water.

Return air is supplied through openings in furnace casing. All return air passages must be kept clear for furnace to function properly. Refer to

MINIMUM CLEARANCE TO FLOORBOARDS, WALLS & SIMILAR COMBUSTIBLE BUILDING MATERIAL. The total unobstructed return air opening size(s) must NOT BE

LESS than specified in SPECIFICATIONS-MINIMUM RETURN AIR. Failure to meet

minimum return air requirements nullifies furnace warranty.

STANDARD FURNACE INSTALLATION

General Installation -

• Install furnace through an exterior wall.

DO NOT install furnace near tilt-out rooms, slide-outs, doors or

• other projections that could obstruct furnace exhaust.

• Locate furnace near midpoint of coach for single furnace applications.

DO NOT install vent in areas where projections or door openings

• come within 6˝ of vent tube opening.

• DO NOT install furnace in an area where wires, pipes, or other objects will interfere with the installation or operation of furnace.

DO NOT directly install furnace on material that restricts return air,

• such as directly on carpet, or soft material (like vinyl).

• If you must install furnace on carpet or soft material, install furnace on cleats, or on a wood or metal panel extending the full width and depth of furnace plus minimum clearances to combustibles.

DO NOT us petroleum or citrus type cleaners on plastic parts, as

• damage may occur.

• The furnace must always be installed level (front to back, side to side) to prevent water intrusion into the interior.

LOCATION

WALL CUTOUT

RECOMMENDED MAXIMUM WALL THICKNESS 2-1/2˝

DO NOT OVERSIZE HOLE

EXTERIOR WALL CUTOUT ABC

RECESS BEZEL (FIG 1-1A) 19-1/2˝ 9-7/8˝ *

*To cut rounded corners: with radius blocks 2-1/8˝ radius

- OVER SIZING CAN RESULT IN WATER LEAKAGE

without radius blocks a 45˚ angle

 CAUTION

PERSONAL INJURY

• DO NOT allow furnace tabs to protrude through side wall cutout opening during installation process until door is installed and tabs are bent over. Tabs have sharp edges.

Place furnace in cavity. Do not have tabs protrude outside exterior wall until door is ready to be installed.

DUCTING (FIG 3-4 A) HORIZONTAL & VERTICAL

HORIZONTAL

PROPER DUCT INSTALLATION IS CRITICAL TO THE OPERATION OF THIS FURNACE

CONTINUOUS USE MATERIALS RATING

DUCTS 9˝ IN LENGTH OR MORE 200˚F.

4˝ DUCTS 250˚F.

METAL BOOTS LESS THAN 9˝ IN LENGTH 250˚F.

Ducting systems can include any combination of discharge openings, as long as static pressure and minimum discharge area requirements are met.

ALL MODELS - (also see STATIC PRESSURE TEST)

REQUIRED MINIMUM DISCHARGE 48 IN REQUIRED MINIMUM RETURN AIR 80 IN

• See MINIMUM CLEARANCE TO FLOORBOARDS, WALLS & SIMILAR COMBUSTIBLE

BUILDING MATERIALS.

• Each 4-inch duct opening provides 12 in

of discharge area. Provide an extra 12 in2of non closeable duct discharge area for each closeable register used.

• Use of 2˝ ducts does not count toward achieving min. discharge req. Ducting in dead air space with no return air, such as holding tank areas, does not count toward achieving min. discharge requirements.

• Adjust ducting installation to obtain air rise of 100˚F - 130˚F.

Flexible Ducting System

When designing Flexible Duct Systems:

• avoid sharp bends or crushed ducts

• stretch all ducts and run them directly to outlets, keeping quantity and angles of bends to a minimum

1. Remove knockout plates from desired outlets.

2. Attach duct adapter to each opening, by inserting flange over casing, locking tab into casing slot and turning adapter 90˚.

3. Attach and secure

FOUR-INCH flexible ducts to adapters.

4. Run ducts to desired location within RV, secure to registers.

5. Additional ducting may be needed to maintain static pressure.

Hard Ducting Floor System

When designing Hard Duct Systems:

• undersize ducting will cause high temperature limiting

• oversize ducting will cause inadequate air flow from registers

• when hard ducting is 1-1/2˝ in depth, an additional flex duct may be needed to maintain installation static requirements

DO NOT install floor registers within 2 feet of return air openings.

•

OPTIONAL INSTALLATION - BOTTOM DISCHARGE (FIG 4)

1. Remove bottom discharge cover plate. This ducting option must

be connected to a ducting system. FIG 12 (parts breakdown) #40 -

GASKET AND PLENUM PLATE KIT is available when attaching furnace.

2. If cutout is required:

DISCHARGES ABCD BOTTOM (FIG 4) 18.0˝ 5.50˝ 10.50˝ .750˝

3. Fasten plenum plate (4-E) over floor cutout. If a gasket and

plenum plate are not used, seal furnace to hard duct system making sure seal is air-tight, continue with

4. Position gasket (4-F) on plenum plate.

5. Set furnace on gasket, gasket must remains in position.

Use additional ducting to maintain correct static pressure.

FLOOR CUTOUT

STEP 5.

VERTICAL

The only ducting option, when using vertical installation, are the top two ducts and two ducts off the back of the casing. This is the only configuration allowed with vertical installation (

FIG 3A).

GAS CONNECTION (FIG. 1)

1. Connect gas line to brass fitting on right side of furnace. Be sure all male pipe threads, other than flare fittings, are treated with a sealing compound resistant to the action of propane (LP) gas.

DO NOT put

sealing compound on flare fittings.

• Remove slide plate (1-E) and gas inlet plug (1-F) from furnace.

• Insert gas line (1-G) through gas inlet plug (DO NOT CUT).

• Connect gas line through gas inlet plug inside furnace casing immediately ahead of gas control valve.

• A 1/8˝ N.P.T. plug is accessible for test gauge connection on gas valve assembly.

2. A 3/8˝ flared fitting connection is provided at gas control valve inlet for gas supply connection to furnace. The gas supply line of the furnace must be of adequate size to provide 11˝ W.C. gas pressure. This pressure must be maintained under maximum flow conditions with all gas appliances in operation.

3. Use two wrenches to hold brass fitting and flare nut when tightening gas line to brass fitting.

DO NOT twist valve assembly (FIG. 5).

ELECTRICAL CONNECTION (FIG 11)

 WARNING

INJURY OR PROPERTY DAMAGE

• Label all wires before disconnecting for service. Wiring errors can cause improper and dangerous operation. Verify proper operation after servicing.

• Disconnect electrical power before servicing.

Conductor Sizing Table - MAX. 10% VOLTAGE DROP - (12 VDC)

CURRENT DRAW (AMPS)

GAGE MAX. LENGTH OF SAE CONDUCTOR (IN FEET) FROM SOURCE TO DEVICE

18 21 19 17 11 9 16 33 29 26 17 13 14 52 46 41 28 21

8 9 10 15 20

 CAUTION

PROPERTY DAMAGE

• This connection is for low-voltage battery or direct current only. Do

not connect to 120- or 240- volts AC.

This unit is designed for negative ground 12 volt DC ONLY. Polarity must be observed so furnace motor will run in proper rotation. attempt to alter to a positive ground system.

12 VOLT DC MODELS

Route 12 volt DC and thermostat leads to left side of control box. Use a minimum of 18 GA wire to minimize voltage drop. The furnace must be installed so electrical components are protected from water. To make electrical connections: see

WIRING DIAGRAM FIG 11

1. Route wiring to left side of furnace.

2. Connect red wire to positive side of power supply.

3. Connect yellow wire to grounded side of power supply.

4. Connect blue wire marked positive thermostat to + side wire of

thermostat using 22-18 GA stranded wire.

5. Connect the other blue wire to the other thermostat lead using

minimum 22-18 GA stranded wire.

For best furnace performance when power supply is from a converter equipped with a charging port, wire the converter to furnace parallel with battery. This provides consistent voltage to furnace, increasing component life, filtering power surges and AC spikes.

DO NOT

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