Bryant CONDENSING GAS FURNACE 340MAV, CONDENSING GAS FURNACE 350MAV, CONDENSING GAS FURNACE 352MAV, CONDENSING GAS FURNACE 355MAV User's Information Manual

USER’S INFORMATION MANUAL

MODEL 340MAV, 350MAV, 352MAV,
355MAV CONDENSING GAS
FURNACE

NOTE TO INSTALLER:

This manual must be left with the equipment user.

MODEL 350MAV (shown)

HIGH EFFICIENCY

GAS FURNACE

A97381

As an ENERGY STAR
Bryant Heating & Cooling
Systems has determined that
this product meets the ENERGY
STAR guidelines for energy
efficiency.

!

WARNING: If the information in this manual

SM

Partner,

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:

— Do not try to light any appliance.

— Do not touch any electrical switch; do not use

any phone in your building.

• Immediately call your gas supplier from a
neighbor’s phone. Follow the gas supplier’s
instructions.

• If you cannot reach your gas supplier, call the
fire department.

— Installation and service must be performed by a

qualified installer, service agency or the gas
supplier.

Do not use this furnace if any part has been under water. Immediately call a qualified service technician
to inspect the furnace and to replace any part of the control system and gas control which has been
under water.

†

WELCOME TO A NEW
GENERATION OF
COMFORT

Congratulations! In light of rising
energy costs, the Plus 90
Plus90
Gas-Fired, Condensing Furnaces are
among the soundest investments
today’s homeowner can make.

Your new furnace is truly a triumph
of technology in home heating. A
revolutionary design employs 2 heat
exchangers to “squeeze” out the maxi­mum amount of heat from the fuel con­sumed. In fact, your new furnace is so
efficient, over 90 percent* of the heat
generated during combustion is cap­tured and delivered inside your home.
That is more than a 33 percent* in­crease in heating efficiency over con­ventional furnaces.

These are among the most energy-effi­cient furnaces you can buy today. They
also are among the safest and most
dependable. We are proud of the tech­nological advances incorporated into
the design of these furnaces. With only
minimal care, your new furnace will
deliver many years of money-saving
home comfort and enjoyment. Spend
just a few minutes with this manual to
learn the operation of your new fur­nace and the small amount of mainte­nance it takes to help keep it operating
at peak efficiency year after year.

* The output capacity and any representations of efficiency

™ and Plus 90i

for this furnace are based on standard Department of
Energy test procedures.

TM

, 340MAV,

TM

Multipoise,

MODELS 340MAV
(SHOWN) AND 350MAV
FIXED-CAPACITY
FURNACES

1

MODEL 355MAV
VARIABLE-CAPACITY
AND MODEL 352MAV
TWO-STAGE
FURNACES

2

INSTALLATION DATA

Date Installed

Dealer Name

Address

City

State Zip

Telephone

FURNACE

Product No.

Model No.

Serial No.

SPLIT-SYSTEM

OUTDOOR UNIT:

Product No.

Model No.

Serial No.

INDOOR COIL:

Product No.

Model No.

Serial No.

2

8

10

5

16

9

6

11

5

4

18

2

17

3

12

7

1

14

15

13

19

8

10

5

15

14
13

16

9

11

5

2

17

3

4

12

18

6

20

1

7
19

FURNACE COMPONENTS

1

Combustion-air intake connection to ensure
contaminant-free air (right or left side).

2

Burner sight glass for viewing burner flame.

3

Burner assembly (inside). Operates with energy­saving inshot burners and hot surface ignitor for safe,
dependable heating.

4

Redundant gas valve. Safe, efficient. Features 1 gas
control with 2 internal shutoff valves.

5

Vent outlet. Uses PVC pipe to carry vent gases from
the furnace’s combustion system (right or left side).

6

Inducer motor. Pulls hot flue gases through the heat
exchangers, maintaining negative pressure for added
safety.

7

Blower access panel safety interlock switch.

8

Air filter and retainer.

9

Condensate drain connection. Collects moisture
condensed from burned gases for disposal into home
drain system.

10

Heavy-duty blower. Circulates air across the heat
exchangers to transfer heat into the home.

11

Secondary condensing heat exchanger (inside).
Wrings out more heat through condensation.
Constructed with Polypropylene-laminated steel to
ensure durability.

12

Primary serpentine heat exchanger (inside).
Stretches fuel dollars with the S-shaped heat-flow
design. Solid construction of corrosion-resistant
aluminized steel means reliability.

13

Control center.

14

3-amp fuse provides electrical and component
protection.

15

Light emitting diode (LED) on control center. Code
lights are for diagnosing furnace operation and
service requirements.

16

Pressure switch(es) ensure adequate flow of flue
products through furnace and out vent system.

17

Rollout switch (manual reset) to prevent
overtemperature.

18

Junction box for 115-v electrical power supply.

19

Transformer (24v) behind control center provides
low-voltage power to furnace control center and
thermostat.

20

Limit switch (manual reset) on 355MAV only.

MODELS 340MAV, 350MAV,
AND 352MAV FURNACES
(UPFLOW POSITION)

MODEL 355MAV
FURNACE (UPFLOW POSITION)

3

3

4

!

!

IMPORTANT FACTS

Your gas furnace uses air from
outside the home for combustion
and venting. It is not to be installed
using in-house air. Therefore, both
pipes must terminate outside the
structure and must not be obstructed
in any way.

To minimize the possibility of serious
personal injury, fire, damage to
your furnace, or improper operation,

carefully follow these safety rules:

• Keep the area around your furnace
free of combustible materials, gaso­line, and other flammable liquids
and vapors.

• Do not cover the furnace, store trash
or debris near it, or in any way block
the flow of fresh air to the unit.

• A furnace installed in an attic or
other insulated space must be kept
free and clear of insulating material.
Examine the furnace area when install­ing the furnace or adding more insula­tion. Some insulation materials may be
combustible.

NOTE:

Do not use this furnace if any
part has been under water. Immedi­ately call a qualified service technician
to inspect the furnace and to replace
any part of the control system and any
gas control which has been under
water.

NOTE:

agency must use only factory­authorized replacement parts, kits,
and accessories when modifying this
product.

The qualified installer or

This furnace contains SAFETY
DEVICES which must be MANU­ALLY RESET. If the furnace is left un­attended for an extended period of
time, have it checked periodically for
proper operation. This precaution will
prevent problems associated with no
heat, such as frozen water pipes, etc.
See “Before You Request a Service
Call” section in this manual.

SAFETY
CONSIDERATIONS

Installing and servicing of heating
equipment can be hazardous due to
gas and electrical components.
Only trained and qualified personnel
should install, repair, or service heat­ing equipment.

5

Untrained personnel can perform basic
maintenance functions such as cleaning
and replacing air filters. All other oper­ations must be performed by trained ser­vice personnel. Observe safety
precautions in this manual, on tags, and
on labels attached to the furnace and
other safety precautions that may apply.

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

Understand the signal words DANGER,
WARNING, and CAUTION. These
words are used with the safety-alert sym­bol. DANGER identifies the most serious
hazards which
sonal injury or death. WARNING signi­fies hazards which
personal injury or death. CAUTION 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
tion, reliability, or operation.

will result in severe per-

could result in

will result in enhanced installa-

STARTING YOUR
FURNACE

Instead of a continuously burning pilot
flame which wastes valuable energy,

your furnace uses an automatic, hot
surface ignition system to light the
burners each time the thermostat
starts your furnace.

important safeguards:

Follow these

6

• Never attempt to light the burners
manually with a match or other source
of flame.

• Read and follow the operating
instructions on the furnace, especially
the item that reads as follows:

Wait 5 minutes to clear out any gas.
Then smell for gas, including near
the floor. If you smell gas,
Follow “B” in the safety information
above on this furnace label. If you
don’t smell gas, go to the next step.

• If a suspected malfunction occurs
with your gas control system, such as
the burners not lighting when they
should, refer to the shutdown proce­dures on the furnace, or in the “Shut­ting Down Your Furnace” section and
call your dealer as soon as possible.

WARNING

If overheating occurs or the
gas valve fails to shut off the
gas supply, turn off the exter­nal manual gas valve to the
furnace BEFORE turning off
the electrical supply. (See Fig.

9.) Failure to follow this warn­ing could result in a fire or ex­plosion, and personal injury
or death.

CHECK AIR FILTER: Before

attempting to start your furnace, be
sure the furnace air filter is clean and in
place. See “Performing Routine Main­tenance” section in this manual.
Then proceed as follows:

STEPS FOR STARTING
YOUR FURNACE

1. Set your room thermostat to the
lowest temperature setting.
(See Fig. 8.)

7

STOP!

4

®

(See Fig. 17.)

9. Open the external manual gas

furnace and wait 1 minute.

valve. (See Fig. 18.)

10. Set room thermostat to a tempera­ture slightly above room tempera-

1

M

3

O

O

P

F

F

F

F

2

C

OR

N

O

OFF

ON

ture. This will automatically
signal the furnace to start.

11. When the furnace receives the

a

8

start signal, the hot surface igni­tor at the main burners is auto-mat­ically heated for 15 to 20 sec.

14

When the microprocessor control

C

L

O

S

E

verifies that there is sufficient
heat to ignite, the gas valve per­mits gas to flow to the main burn­ers. After ignition and a time delay
of about 35 sec, the furnace blower

ON

will start. Variable-capacity fur­naces start at low speed until the
control makes the necessary
adjustments to operate the blower
at either the low- or high-stage
speed.

9

NOTE:

If the burners fail to ignite after

15

4 attempts, the furnace control system
will lock out. If lockout occurs, main
burners fail to light, or blower does not
come on, shut down the furnace and
call your dealer for service.

10

2. Close the external manual gas
valve. (See Fig. 9.)

3. Turn off electrical supply to the
furnace. (See Fig. 10.)

4. Remove the main furnace door.
(See Fig. 11.)

5. Gas valve will have EITHER a con­trol switch or control knob to turn
OFF or ON. Turn control switch or
knob on the gas valve to the OFF
position and wait 5 minutes. (See
Fig. 12 or 13.) Then smell for gas,
including near the floor. If you
smell gas,
furnace label. If you don’t smell
gas, go to next step.

6. After waiting 5 minutes, turn con­trol switch or knob on the gas
valve to the ON position.
(See Fig. 14 or 15.)

7. Replace main furnace door.
(See Fig. 16.)

8. Turn on electrical supply to the

STOP! Follow “B” on

12. Set your thermostat to the temper­ature that satisfies your comfort
requirements.

11

SUGGESTION: Setting the ther­mostat back a few degrees and
compensating for the difference
with warmer clothing can make a

1

M

3

O

O

P

F

F

F

F

2

C

ON

OR

OFF

ON

big difference in your fuel con­sumption on extremely cold days.
The few degrees at the top of your
thermostat “comfort level” are the
most costly degrees to obtain.

When room temperature drops
below the temperature selected
on the thermostat, the furnace
will be switched on automatically.

12

When room temperature reaches
the degree selected on the thermo­stat, the furnace will be switched
off automatically.

Some thermostats have a FAN
mode with 2 selections, AUTO

F

O

F

and ON. When thermostat is set
to AUTO, the furnace blower
cycles on and off, controlled by
the thermostat. In ON mode, the
furnace blower runs continu­ously. This keeps the temperature
level in your home more evenly
balanced. It also continuously

13

filters the indoor air.

5

O

!

P

E

N

16

17

The following procedures must be
followed:

1. Set your room thermostat to the
lowest temperature setting.
(See Fig. 19.)

2. Close the external manual gas
valve. (See Fig. 9.)

3. Turn off electrical supply to the
furnace. (See Fig. 20.)

4. Remove main furnace door.
(See Fig. 11.)

5. Turn control switch or knob on the
gas valve to OFF position.
(See Fig. 21 or 22.)

6. Replace main furnace door.
(See Fig. 16.)

7. If the furnace is being shut down
because of a malfunction, call
your dealer as soon as possible.

!

CAUTION

Furnace is not to be installed,
operated, and then turned off
and left turned off in an unoc­cupied structure during winter.
(See winterizing procedures in
maintenance section.)

20

PERFORMING
ROUTINE
MAINTENANCE

With proper maintenance and care, your
furnace will operate economically and
dependably. Instructions for basic main­tenance are found on this and the follow­ing pages. However, before beginning
maintenance, follow these safety pre­cautions:

WARNING

Turn off electrical power sup­ply to your furnace before re­moving the main furnace door
to service or perform mainte­nance. Failure to follow this
warning could result in per­sonal injury or death.

!

CAUTION

Although special care has
been taken to minimize sharp
edges, be extremely careful
when handling parts or reach­ing into the furnace.

FILTERING OUT
TROUBLE

A dirty air filter will cause a loss of airflow
in your duct system. When excessive loss
of airflow occurs, the furnace may cycle
on its safety controls. If this condition is
left unattended, the furnace will eventu­ally lock out. It is recommended that the
furnace air filter be checked every 3 or 4
weeks and cleaned if necessary.

18

SHUTTING DOWN
YOUR FURNACE

Should you need to shut down your
furnace for service or maintenance,
you will need to turn the furnace off.

®

19

!

CAUTION

Never operate your furnace

1

M

3

O

O

P

F

F

F

F

2

C

ON

OR

OFF

ON

without the air filter in place.
Doing so may damage the fur­nace blower motor. An accu­mulation of dust and lint on
internal parts of your furnace
can cause a loss of efficiency.

21

The air filter is normally located in the
blower compartment (See Fig. 3 or 4)
or in the factory-supplied filter cabinet
attached to the side or bottom of the
blower cabinet. If air filter has been

F

O

F

installed in another location, contact
your dealer for instructions. To inspect,
clean, and/or replace the air filter(s),
follow these steps:

1. Turn off electrical supply to fur­nace. (See Fig. 20).

2. Remove door/access panel

22

• AIR FILTER(S) LOCATED IN

6

BLOWER COMPARTMENT
a. Remove main furnace door.

(See Fig. 23)

b. Remove blower access panel.

(See Fig. 24)

NOTE: It will be necessary to

remove 2 screws

• AIR FILTER LOCATED IN FIL­TER CABINET

a. Remove filter cabinet door (See

Fig. 36 and 37)

NOTE: It will be necessary to

remove 1 thumbscrew

3. Remove air filter from furnace.

• AIR FILTER LOCATED IN
BLOWER COMPARTMENT
BOTTOM:

a. Slide filter retainer sideways

until it is free of latch. (See
Fig. 25)

b. Slide air filter out of furnace.

(See Fig. 26)

• AIR FILTER(S) LOCATED IN
BLOWER COMPARTMENT
SIDE:

a. Remove filter retainer from

latch. (See Fig. 27.)

b. Gently remove air filter and

carefully turn the dirty side up
(if dirty) to avoid spilling dirt
from the filter. (see Fig. 28)

• AIR FILTER LOCATED IN FIL­TER CABINET:

a. Slide air filter out of furnace.

Keep dirty side up (if dirty) to
avoid spilling dirt. (See Fig. 38
and 39)

a. Factory specified disposable

media filter – Do not clean. If
dirty, replace only with media fil­ter having the same part number
and size. Install with airflow
direction arrow pointing towards
blower.

b. Electronic air cleaner (EAC) –

Refer to EAC owner’s Manual
for maintenance information.

25

26

27

necessary. Spray water through fil-
ter in the opposite direction of air­flow. Allow filter to dry.

6. Reinstall clean air filter

7. Reinstall filter retainer (for blower
compartment locations only)

8. Replace blower access panel and
main furnace door (See Fig. 29
and 30) or filter cabinet door (Fig.
40 and 41)

9. Turn on electrical supply to fur­nace.

If your furnace air filter needs to be
replaced, be sure to use the same size
and type of filter that was originally
supplied. Use the furnace filter table
and compare your furnace size with
the proper filter size.

UPFLOW FURNACE AIR

FILTER TABLE

AIR FILTER LOCATED IN BLOWER COMPARTMENT

FURNACE

CASING

WIDTH

(IN.)

17-1/2 (1) 16 x

21 (1) 16 x

24-1/2 (1 or 2) 16

AIR FILTER LOCATED IN FILTER CABINET:

FILTER

CABINET

HEIGHT

(IN)

16 (1) 16 x 25 x 1*

20 (1) 20 x 25 x 1*

24 (1) 24 x 25 x 1*

* Factory-provided with the furnace. Filters may be

field modified by cutting filter material and support
rods (3) in filters. Alternate sizes and additional fil-
ters may be ordered from your dealer.

FILTER SIZE

(IN.)

Side

Return

25 x 1*

25 x 1

x 25 x 1

FILTER SIZE

or (1) 16 x 25 x 4-5/16

or (1) 20 x 25 x 4-5/16

or (1) 24 x 25 x 4-5/16

Bottom
Return

(1) 16 x
25 x 1*

(1) 20 x
25 x 1*

(1) 24 x
25 x 1*

(IN.)

FILTER

TYPE

Cleanable

Cleanable

Cleanable

FILTER

TYPE

Cleanable

Disposable

Cleanable

Disposable

Cleanable

Disposable

23

24

4. Inspect the filter. If torn, replace it.

NOTE: If washable filter that was

shipped with the furnace has been
replaced by:

28

5. Wash filter (if dirty) in sink, bath­tub, or outside with a garden hose.
Always use cold tap water. A mild
liquid detergent may be used if

7

!

CAUTION

Use care when cutting support
rods in filters to protect
against flying pieces and
sharp rod ends. Wear safety
glasses, gloves, and appropri­ate protective clothing. Failure
to follow this caution could re­sult in personal injury.

!

CAUTION

If dirt, rust, soot, or scale accu­mulations are found, call your
dealer. Do not operate your
furnace.

29

30

COMBUSTION AREA
AND VENT SYSTEM

Visually inspect the combustion area
and vent system before each heating
season. Make sure that all PVC pipes
leading into the combustion area and
vent are free from any cracks and sags.
Also check the combustion-air intake
and vent pipes on the outside of your
home for blockage.

When dirt, soot, scale, or rust is
allowed to build up, your furnace can
suffer a loss of efficiency and perform
improperly. Accumulations on the
main burners can result in firing out of
normal sequence. This delayed igni­tion creates an alarmingly loud sound.

!

CAUTION

If your furnace makes an espe­cially loud noise when the
main burners light, shut down
your furnace and call your
dealer.

To inspect the combustion area and
vent system, you will need a flashlight.
Refer to Fig. 3 or 4, and proceed as
follows:

1. Turn off gas and electrical supplies
to the furnace and remove
the main furnace door. (See Fig. 9,
10, and 11.)

2. Remove burner enclosure front.
(See Fig. 31 or 32.)

Inspect the gas burners and ignitor
area for dirt, rust, soot, or scale.

3. Inspect the combustion-air and
vent pipes for sags, holes, cracks,
or disconnections.

!

DANGER

If holes are found in the pipes
or if any portion has become
disconnected, toxic fumes
can escape into your home.
DO NOT OPERATE YOUR
FURNACE. Call your dealer for
service.

4. Reinstall burner enclosure front.

5. If your furnace is free of the above
conditions, replace main furnace
door and turn on electrical and gas
supplies to your furnace.
(See Fig. 16, 17, and 18.)

6. Start the furnace and observe its
operation. Watch the burner flames
to see if they are clear blue, almost
transparent. (See Fig. 33.) If you
observe a suspected malfunction,
or the burner flames are not clear
blue, call your dealer.

31

32

33

HEADING SOUTH
FOR THE WINTER?

DON’T FORGET YOUR
FURNACE!

!

CAUTION

If the furnace is installed in an
unconditioned space where
the ambient temperatures may
be 32°F or lower, freeze protec­tion measures must be taken.

Since the furnace uses a condensing
heat exchanger, some water will accu­mulate in the unit as a result of the heat
transfer process. Therefore, once it
has been operated, it cannot be turned
off and left off for an extended period
of time when temperatures will reach
32°F or lower unless winterized. Fol­low these procedures to winterize your
furnace:

1. Obtain propylene glycol (RV/
swimming pool antifreeze or
equivalent).

!

CAUTION

Do not use ethylene glycol
(Prestone II antifreeze coolant
or equivalent). Failure of plas­tic components will occur.

2. Turn off electrical supply to the
furnace. (See Fig. 20.)

3. Remove main furnace door.
(See Fig. 23.)

4. Remove upper inducer housing
drain connection cap.
(See Fig. 34.)

5. Connect field-supplied 1/2-in.
ID tube to upper inducer housing
drain connection.

6. Insert field-supplied funnel into
tube.

8

7. Pour 1 quart of antifreeze into
funnel/tube. Antifreeze should
run through inducer housing,
overfill condensate trap, and flow
into open field drain.
(See Fig. 35.)

8. Remove funnel and tube from
inducer housing and replace drain
connection cap and clamp.

9. Replace main furnace door.
(See Fig. 30.)

34

35

A CHECK-UP
CHECKLIST

Your furnace represents an important
investment in your family’s comfort
and your home’s value. To keep it
performing properly and as a preven­tative to future problems, have a trained
service specialist give your furnace a
professional check-up annually. The
following checklist can be used as a
guideline to proper service:

• Inspect all flue gas passages, burn­ers, heat exchangers, coupling
box(es), and inducer assembly.

• Inspect all combustion-air and vent
piping inside structure and pipe termi­nations outside the structure.

• Check gas pipes leading to and
inside of your furnace for leaks.

• Inspect and clean the blower motor
and wheel.

NOTE

: The inducer and blower motors
are pre-lubricated and require no addi­tional lubrication. These motors can be
identified by the absence of oil ports on
each end of the motor.

• Inspect and change or clean air fil­ter(s) if necessary.

• Inspect all supply- and return-air
ducts for obstructions, air leaks, and
insulation. Remedy any problem when
necessary.

• Inspect the return-air duct connec­tion(s) at the furnace to ensure it is
physically sound, sealed to the furnace
casing, and terminates outside the
space containing the furnace.

• Inspect electrical wiring, connec­tions, and components for loose
connections.

• Perform an operational checkout to
determine whether your furnace is
working properly and if it requires
adjustments.

• Inspect all condensate drain tubes
and condensate trap assembly for
leaks. The condensate removal system
should be cleaned annually by a quali­fied service agency. Refer to the Ser­vice and Maintenance Instructions for
further information.

• Examine the physical support of the
furnace. The support should be sound
with no cracks, sagging, gaps, etc.
around the base.

• Check furnace for any obvious signs
of deterioration.

36

37

38

9

39

40

BEFORE YOU
REQUEST A
SERVICE CALL

If your furnace is not operating or not
performing properly, you may save
the expense of a service call by check­ing a few things yourself before calling
for service.

FOR INSUFFICIENT AIRFLOW:

• Check for dirty air filter(s).

• Check for blocked return-air or sup-

ply-air grilles throughout your home.
Ensure they are open and unobstructed.

If problem still exists, call your dealer
for service.

IF FURNACE FAILS TO OPERATE:

Follow this checklist step by step,
advancing to the next step only if fur­nace fails to start.

• Check thermostat for proper tem­perature. Is thermostat set above room
temperature?

• Is thermostat set to HEAT?

• Check fuses and circuit breakers. Is

electrical supply on?

• Is manual shutoff valve in gas supply
pipe in open position? (Follow start-up
procedures if you open gas valve.)

NOTE:

Turn off electrical supply

before continuing with checklist.

shut down the furnace and call for ser­vice. See “Shutting Down Your Fur­nace” section in this manual.

• Check for obstructions around the
vent termination outside the structure.

If your furnace still fails to operate, call
your service representative.

For your convenience, record the fur­nace product and serial numbers on
page 2. Should you ever require ser­vice, you will have ready access to the
information needed by your service
representative.

This furnace has an LED operation
and fault code display to aid the
installer, service technician, or home­owner while installing or servicing the
unit. The LED code can be seen by
removing the access door and viewing
LED(s) through the view port in the
blower access panel.

NOTE:

panel or turning off the 115-v electri­cal power supply will terminate LED
diagnostic code display and erase the
memory.

To decipher the meaning of the LED
code, and suggested action, the follow­ing cross-reference can be used.

Removing the blower access

41

• Is control switch or knob on gas
valve in ON position? (Follow start-up
procedures if you must reset switch or
knob to ON position.)

• Check manual reset flame rollout
switch located on the burner box in
combustion area. (See Fig. 3 or 4.) If
furnace has experienced high tempera­ture conditions, this switch will shut
off the furnace. Reset it by pushing the
button on the switch. If it trips again,

10

MODEL 340MAV AND 350MAV DIAGNOSTIC CHART

(See Fig. 3.)

FAULT
CODE FAULT CODE DESCRIPTION CHECKLIST

13 or 33 Limit Switch Lockout

14 or 34

24 Furnace Fuse Open Check for blown fuse and possible short in 24-v wiring.

31 Pressure Switch Not Closed

12, 21, 22,
or 23

No Fault
Code
Signaled

Ignition Lockout or
Ignition Proving Fault

Any Other Fault Code Call dealer for service.

Furnace Fails to Operate and No
Fault is Signaled

NOTES:

1. Light on continuously means control has power and working properly.

2. The fault code is a 2-digit number. The first digit is determined by the number of short flashes of the light and the second digit is determined by number of long flashes
of the light.

Check for dirty air filter.
Check for blocked return-air or supply-air grilles.

Check to be sure manual shutoff valve in gas supply pipe is in the open position. (Follow
start-up procedure if you open gas line.)
NOTE: Turn off the electrical supply and remove access doors before continuing with this
checklist.
Check to be sure control switch or knob on gas valve is in ON position. (Follow start-up pro­cedures if you must reset switch or knob to ON position.)
Check for disconnected ground wire.

Check to make sure that all PVC pipes leading into the combustion-air intake and vent/
exhaust are free from any cracks and sags. Also check the combustion-air intake and vent/
exhaust pipes on the outside of your home for blockage.
Check for low propane gas pressure.

Check thermostat for proper temperature setting.
Check for blown fuses and circuit breakers.
Check to be sure blower access panel is properly in place.

MODEL 352MAV DIAGNOSTIC CHART

(See Fig. 3.)

FAULT
CODE FAULT CODE DESCRIPTION CHECKLIST

13 or 33 Limit Switch Lockout

14 or 34

24 Furnace Fuse Open Check for blown fuse and possible short in 24-v wiring.

31, 32, 43 Pressure Switch Fault

12, 21, 22,
23 or 45

No Fault
Code
Signaled

Ignition Lockout or
Ignition Proving Fault

Any Other Fault Code Call dealer for service.

Furnace Fails to Operate and No
Fault is Signaled

NOTES:

1. Light on continuously means control has power and working properly.

2. The fault code is a 2-digit number. The first digit is determined by the number of short flashes of the light and the second digit is determined by number of long flashes
of the light.

Check for dirty air filter.
Check for blocked return-air or supply-air grilles.

Check to be sure manual shutoff valve in gas supply pipe is in the open position. (Follow
start-up procedure if you open gas line.)
NOTE: Turn off the electrical supply and remove access doors before continuing with this
checklist.
Check to be sure control switch on gas valve is in ON position. (Follow start-up procedures if
you must reset switch to ON position.)
Check for disconnected ground wire.

Check to make sure that all PVC pipes leading into the combustion-air intake and vent/
exhaust are free from any cracks and sags. Also check the combustion-air intake and vent/
exhaust pipes on the outside of your home for blockage.
Check for low propane gas pressure.

Check thermostat for proper temperature setting.
Check for blown fuses and circuit breakers.
Check to be sure blower access panel is properly in place.

11

MODEL 355MAV DIAGNOSTIC CHART

(See Fig. 4.)

FAULT
CODE FAULT CODE DESCRIPTION CHECKLIST

12 Blower Calibration Lockout Check for dirty air filter.

13 or 33 Limit Switch Lockout

14 or 34

24 Furnace Fuse Open Check for blown fuse and possible short in 24-v wiring.

31, 32, or 43 Pressure Switch Fault Check to make sure that all PVC pipes leading into the combustion-air intake and vent/

42

44 Blower Calibration Fault

21, 22, 23,
or 41

No Fault
Code
Signaled

Ignition Lockout or
Ignition Proving Fault

Inducer Outside Valid
Speed Range

Any Other Fault Code or Either of the
Red Lights On Continuously

Furnace Fails to Operate and No
Fault is Signaled

NOTES:

1. Red light 1 on continuously means furnace is operating in emergency heat.

2. Red light 2 on continuously means the microprocessor board has malfunctioned.

3. Yellow light on continuously means furnace is operating in high heat.

4. Green light on continuously means furnace is operating in low heat.

5. The fault code is a 2-digit number. The first digit is determined by the number of flashes of the yellow light and the second digit is determined by number
of flashes of the green light.

Check for blocked return-air or supply-air grilles.
Turn electrical supply off, then back on. Set the thermostat to call for heat.

Check to be sure manual shutoff valve in gas supply pipe is in open position. (Follow start­up procedure if you open gas line.)
NOTE: Turn off the electrical supply and remove access doors before continuing with this
checklist.
Check to be sure control switch or knob on gas valve is in ON position. (Follow start-up
procedures if you must reset switch or knob to ON position).
Check for disconnected ground wire.

exhaust are free from any cracks and sags. Also check the combustion-air intake and
vent/exhaust pipes on the outside of your home for blockage.
Check for low propane gas pressure.

Check for dirty air filter(s).
Check for blocked return- or supply-air grilles.
NOTE: In zoned applications, fault 44 may flash during operation when a single zone is
calling for heat. When other zones call for heat, or the unit cycles, the fault should clear
itself. Call for service if fault 12 develops.

Call dealer for service.

Check thermostat for proper temperature setting.
Be sure thermostat is set to HEAT.
Check for blown fuses and circuit breakers.
Check to be sure blower access panel is properly in place.

© 2001 Bryant Heating & Cooling Systems, 7310 W. Morris St., Indpls., IN 46231

12 Printed in U.S.A. Catalog No. 5335-202 3-01

Cancels: OM05-30 OM05-32