Carrier WEATHERMAKER INFINITY 58MCA User manual

MULTIPOISE, CONDENSING 58MCA, 58MTA, 58MVP, 58MXA
GAS FURNACE
USER: Please read all manuals and
retain manuals for future reference.
WARNING:
Fire or Explosion Hazard. Failure to follow safety
warnings exactly could result in serious injury
death or property damage.
!
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.
NOTE TO INSTALLER:
THIS MANUAL MUST BE LEFT WITH THE
EQUIPMENT USER.
A93007
— 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.
• Leave the building immediately.
• 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.
WARNING:
Carbon Monoxide is invisible, odorless, and toxic!
Carrier Corporation recommends a carbon mon-
oxide alarm in your home, even if you do not own
a gas appliance. Locate the carbon monoxide
alarm in the living area of your home and away
from gas appliances and doorways to attached
garages. Follow the alarm manufacturer’s instruc-
tion included with the alarm.
!
®
• • • • • • • • • • • • • • •
ULTRA HIGH EFFICIENCY
GAS FURNANCE
®

2
WELCOME TO A NEW GENERATION
OF COMFORT
Congratulations! In light of rising energy costs, the 58MXA,
58MCA, 58MTA, and WeatherMaker Infinity, Multipoise, 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 heat-
ing. A revolutionary design employs 2 heat exchangers to
“squeeze” out the maximum amount of heat from the fuel con-
sumed. In fact, your new furnace is so efficient, over 90%AFUE*
of the heat generated during combustion is captured and delivered
inside your home. That is more that a 33% AFUE* increase in
heating efficiency over conventional furnaces.
These are among the most energy-efficient furnaces you can buy to-
day. 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 for this furnace are based on standard
U.S. Department of Energy test procedures.
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.
1
MODELS 58MXA (SHOWN) AND
58MCA FIXED-CAPACITY FURNACES
ed art
®
•••••••••••••••
ULTRA HIGH EFFICIENCY
GAS FURNANCE
®
2
MODEL 58MVP
VARIABLE-CAPACITY
AND MODEL 58MTA
TWO-STAGE FURNACES
As an ENERGY STAR®
partner, Carrier Corporation
has determined that this
product meets the ENERGY
STAR®guidelines for
energy efficiency.
CERTIFIED

3
FURNACE COMPONENTS
Combustion-air intake connection to ensure contami-
nant-free air (right or left side).
Burner sight glass for viewing burner flame.
Burner assembly (inside). Operates with energy-saving
inshot burners and hot surface ignitor for safe,
dependable heating.
Redundant gas valve. Safe, efficient. Features 1 gas con-
trol with 2 internal shutoff valves. Valve appearance var-
ies with furnace model.
Vent outlet. Uses PVC pipe to carry flue gas from the fur-
nace’s combustion system (right or left side).
Inducer motor. Pulls hot flue gases through the heat ex-
changers, maintaining negative pressure for added safety.
Blower access panel safety interlock switch.
Air filter and retainer.
Condensate drain connection. Collects moisture con-
densed from burned gases for disposal into home drain
system. (Location in furnace varies.)
1
2
3
4
5
6
7
8
9
need art
3
MODELS 58MXA, 58MCA, AND 58MTA
FURNACES (UPFLOW POSITION)
Heavy-duty blower. Circulates air across the heat ex-
changers to transfer heat into the home.
Secondary condensing heat exchanger (inside). Wrings
out more heat through condensation. Constructed with
polypropylene-laminated steel to ensure durability.
Primary serpentine heat exchanger (inside). Stretches fuel
dollars with the S-shaped heat-flow design. Solid con-
struction of corrosion-resistant aluminized steel means re-
liability.
Furnace control board.
3-amp fuse provides electrical and component protection.
Light emitting diode (LED) on furnace control board.
Code light is for diagnosing furnace operation and service
requirements.
Pressure switch(es) ensure adequate flow of flue gas
through furnace and out vent system.
Rollout switch (manual reset) to prevent overtemperature.
Junction box for 115-v electrical power supply. (May be
located on right or left side)
Transformer (24v) behind furnace control board pro-
vides low-voltage power to furnace control board and
thermostat.
Limit switch (manual reset) on 58MVP only.
10
11
12
13
14
15
16
17
18
19
20
8
10
5
16
9
6
11
5
418
217
3
12
7
1
14
15
13
19
810
5
15
14
13
16
9
11
5
217
3
4
12
18
6
20
1
7
19
4
MODEL 58MVP
FURNACE (UPFLOW POSITION)

4
SAFETY CONSIDERATIONS
Recognize safety information. This is the safety-alert sym-
bol . 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 sym-
bol. 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 is used to identify unsafe practices which
would result in minor personal injury or product and prop-
erty damage. NOTE is used to highlight suggestions which
will result in enhanced installation, reliability or operation.
5
To minimize the possibility of serious personal injury, fire,
furnace damage, or improper operation;
carefully follow
these safety rules:
•Your gas furnace uses air from outside the home for com-
bustion and venting. It is not to be installed using indoor air
for combustion. Both pipes must terminate outside the struc-
ture and must not be obstructed in any way. Do not block or
obstruct the furnace opening or area around the furnace.
•Keep the area around your furnace free of combustible
materials, gasoline, and other flammable liquids and vapors.
6
•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 fur-
nace area when the furnace is installed or when insulation is
added. Some materials may be combustible.
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.
STARTING AND SHUTTING DOWN
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.
Follow these important safeguards:
•Never attempt to manually light the burners with a match
or other source of flame.
•Read and follow the operating instructions on inside of
main furnace door, 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,
STOP! 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 do not light when they should,
refer to the shutdown procedures on inside of main furnace
door, or in the “Shutting Down Your Furnace”section and
call your dealer as soon as possible.
•
CHECK AIR FILTER: Before attempting to start your
furnace, be sure the furnace 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 set-
ting. (See Fig. 8.)
2. Close the external manual gas valve. (See Fig. 9.)
!
WARNING
If overheating occurs or the gas valve fails to shut
off the gas supply, turn off the manual gas valve to
the furnace BEFORE turning off the electrical sup-
ply. (See Fig. 9.) Failure to follow this warning
could result in a fire or explosion, and personal in-
jury or death.
7
!

5
8
910
3. Turn OFF electrical supply to the furnace. (See Fig. 10.)
4. Remove main furnace door. (See Fig. 11.)
11
5. The gas valve will have EITHER a control knob or con-
trol switch to turn off and on. Turn the control knob or
switch on the gas valve to the OFF position and wait
5 minutes. (See Fig. 12.)
12
6. After waiting 5 minutes, turn the control knob or switch
on the gas valve to the ON position. (See Fig. 13.)
13
14
15 16
7. Replace main furnace door. (See Fig. 14.)
8. Turn ON the electrical supply to the furnace and wait 1
minute. (See Fig. 15.)
9. Open the external manual gas valve. (See Fig. 16.)
10. Set the room thermostat to a temperature slightly
above the room temperature. This will automatically
signal the furnace to start.
11. When the furnace receives the start signal, the inducer is
started. When the combustion air is built up to sufficient
levels, the hot surface ignitor is energized. After the hot
surface ignitor is heated for 17 seconds, the gas valve per-
mits gas to flow to the main burners. After ignition and a
time delay of about 60 sec, the furnace blower 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-heat speed.
NOTE: If the burners fail to ignite after 4 attempts, the fur-
nace 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.
12. Set your thermostat to the temperature that satisfies
your comfort requirements. SUGGESTION: Setting
®
C
L
O
S
E
O
F
F
2
3
1
M
P
ON
O
F
F
C
ON
OFF
OR
O
F
F
2
3
1
M
P
ON
O
F
F
C
ON
OFF
OR
O
P
E
N

6
the thermostat back a few degrees—and compensating
for the difference with warmer clothing—can make a big
difference in your fuel consumption. The few degrees at
the top of your thermostat “comfort level’’ are the most
costly degrees to obtain.
When the room temperature drops below the temperature
selected on the thermostat, the furnace will switch on auto-
matically. When the room temperature reaches the tempera-
ture selected on the thermostat, the furnace will be switched
off automatically.
Some thermostats have a “FAN’’ mode with 2 selections:
AUTO and ON. When set on AUTO, the furnace blower
cycles on and off. In the ON mode, the furnace blower runs
continuously. Continuous fan keeps the temperature level in
your home more evenly balanced. It also permits the indoor
air to be continuously filtered. ComfortFan™–On all but the
58MCA, the blower speed can be increased or decreased if
desired due to change of seasons, large gatherings in your
home, etc. Simply change your “FAN”from “on”to “off”(or
“auto”depending on your thermostat), and then return to
“on.”The blower will switch to the next highest speed. There
are at least 3 speeds to choose from. If the blower is running
on its highest speed, a request to change will direct the blower
to return to its lowest speed.
SHUTTING DOWN YOUR FURNACE
Should you ever need to shut down your furnace for service
or maintenance, you will need to turn the furnace off. The
following procedures must be followed:
1. Set your room thermostat to the lowest temperature
setting. (See Fig. 17.)
17
2. Close the external manual gas valve (See Fig. 9.)
3. Turn off electrical supply to the furnace. (See Fig. 18.)
18
4. Remove main furnace door. (See Fig. 11.)
5. Turn the switch on the gas valve to the OFF position. (See
Fig. 19.)
19
6. Replace the main furnace door. (See Fig. 14.)
7. If the furnace is being shut down because of a malfunc-
tion, call your dealer as soon as possible.
PERFORMING ROUTINE
MAINTENANCE
NOTE: The qualified installer or agency must use only
factory-authorized replacement parts, kits, and accessories
when modifying this product.
Installing and servicing heating equipment can be hazard-
ous due to gas and electrical components. Only trained and
qualified personnel should install, repair, or service heating
equipment.
Untrained personnel can perform basic maintenance func-
tions such as cleaning and replacing air filters. All other
operations must be performed by trained service person-
nel. Observe safety precautions in this manual, on tags, and
on labels attached to the furnace, and other safety precautions
that may apply.
With proper maintenance and care, your furnace will operate
economically and dependably. Instructions for basic mainte-
nance are found on this and the following pages. However,
before beginning maintenance, follow these safety precautions:
®
CAUTION
Furnace is not to be installed, operated, and then
turned off and left turned off in an unoccupied
structure during winter. (See winterizing proce-
dures in maintenance section). Freeze damage to
furnace could occur.
WARNING
Turn off electrical power supply to your furnace
before removing the access doors to service or
perform maintenance. A failure to follow this
warning could result in personal injury or death.
O
F
F
2
3
1
M
P
ON
O
F
F
C
ON
OFF
OR
!
!

7
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 unat-
tended, the furnace will eventually lock out. It is recom-
mended that the furnace air filter be checked every 3 or 4
weeks and cleaned if necessary.
If installed with factory specified disposable media filter,
check or replace filter before each heating and cooling sea-
son. Replace disposable media filter at least once a year.
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 furnace casing. If air
filter has been installed in another location, contact your deal-
er for instructions. To inspect, clean, and/or replace the air
filter(s), follow these steps:
1. Turn off electrical supply to furnace. (See Fig. 18)
2. Remove door/access panel
•AIR FILTERS(S) LOCATED IN BLOWER COMPART-
MENT
a. Remove main furnace door. (See Fig. 20)
b. Remove blower access panel. (See Fig. 21)
NOTE: It will be necessary to remove 2 screws
•AIR FILTER LOCATED IN FILTER CABINET
a. Remove filter cabinet door (See Fig. 22 and 23)
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. 24)
b. Slide air filter out of furnace. (See Fig. 25)
•AIR FILTER(S) LOACTED IN BLOWER COMPART-
MENT SIDE:
a. Remove filter retainer from latch. (See Fig. 26.)
b. Gently remove air filter and carefully turn the dirty side up
(if dirty) to avoid spilling dirt from the filter. (see Fig. 27)
•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. 28 and 29)
4. Inspect the filter. If torn, replace it.
NOTE: If washable filter that was shipped with the furnace has
been replaced by:
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 point-
ing towards blower.
20 21
22 23
24 25
26 27
b) Electronic air cleaner (EAC) –Refer to EAC Owner’s
Manual for maintenance information.
5. If washable filter, wash filter (if dirty) in sink, bathtub, or out-
side with a garden hose. Always use cold tap water. A mild
liquid detergent may be used if necessary. Spray water
through filter in the opposite direction of airflow.Allow filter
CAUTION
Although special care has been taken to minimize
sharp edges, be extremely careful when handling
parts or reaching into the furnace.
CAUTION
Never operate your furnace without a 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.
!
!

8
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.
30 and 31) or filter cabinet door (Fig. 32 and 33.)
9. Turn on electrical supply to furnace. If your furnace air filter
needs to be replaced, be sure to use a factory-authorized filter
of the same size that was orginally supplied. Use the filter
tables and compare your furnace size with the proper filter
size.
28 29
30 31
32 33
* Factory-provided with the furnace. Filters may be field modified by cutting-
filter material and support rods (3) in filters. Alternate sizes and additional
filters may be ordered from your dealer.
† Upflow only.
COMBUSTION AREA AND VENT
SYSTEM
Visually inspect the combustion are 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. Check the combustion-air intake and vent pipe 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 improper-
ly.Accumulations on the main burners can result in firing out
of normal sequence. This delayed ignition creates an alarm-
ingly loud sound.
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 the 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. 34 or 35.)
Inspect the gas burners, ignitor area, and remainder of furnace
for dirt, rust, soot, or scale.
FURNACE AIR FILTER TABLE
AIR FILTER LOCATED IN BLOWER COMPARTMENT
FURNACE
CASING
WIDTH (IN.)
FILTER SIZE (IN)
FILTER
TYPESide Return † Bottom Return
17-1/2 (1) 16 x 25 x 1* (1) 16 x 25 x 1* Cleanable
21 (1) 16 x 25 x 1 (1) 20 x 25 x 1* Cleanable
24-1/2 (1 or 2) 16 x 25 x 1 (1) 24 x 25 x 1* Cleanable
AIR FILTER LOCATED IN FILTER CABINET
FILTER
CABINET
HEIGHT (IN)
FILTER
SIZE (IN)
FILTER
TYPE
16 (1) 16 x 25 x 1*
or (1) 16 x 25 x 4-5/16 Cleanable or Disposable
20 (1) 20 x 25 x 1*
or (1) 20 x 25 x 4-5/16 Cleanable or Disposable
24 (1) 24 x 25 x 1*
or (1) 24 x 25 x 4-5/16 Cleanable or Disposable
CAUTION
Use care when cutting support rods in filters to
protect against flying pieces and sharp rod ends.
Wear safety glasses, gloves, and appropriate pro-
tective clothing. Failure to follow this caution
could result in personal injury.
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 FUR-
NACE. Call your dealer for service.
CAUTION
If your furnace makes an especially loud noise
when the main burners light, shut down your fur-
nace and call your dealer.
CAUTION
If dirt, rust, soot, or scale accumulations are found,
call your dealer. Do not operate your furnace.
!
!
!
!

9
3. Inspect the combustion-air and PVC vent pipes for sags,
holes, cracks, or disconnections. Horizontal portions of
pipes must slope downward toward furnace.
34 35
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 the furnace. (See Fig. 14, 15, and 16.)
6. Start the furnace and observe its operation. Watch the
burner flames to see if they are clear blue, almost transpar-
ent. (See Fig. 36.) If you observe a suspect malfunction,
or the burner flames are not clear blue, call your dealer.
36
HEADING SOUTH FOR THE WINTER?
DON’T FORGET YOUR FURNACE!
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).
2. Turn off electrical supply to the furnace. (See Fig. 18.)
3. Remove main furnace door. (See Fig. 20.)
4. Remove upper inducer housing drain connection cap.
(See Fig. 37.)
37
38
5. Connect field-supplied 1/2-in. ID tube to upper inducer
housing drain connection.
6. Insert field-supplied funnel into tube.
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. 38.)
8. Remove funnel and tube from inducer housing and
replace drain connection cap and clamp.
9. Replace main furnace door. (See Fig. 31.)
10. Propylene glycol need not be removed before restarting
furnace.
A CHECK-UP CHECKLIST
Your furnace represents an important investment in your fami-
ly’s comfort and your home’s value. To keep it performing
properly and to prevent 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, cou-
pling box(es), and inducer assembly.
•Inspect all combustion-air and vent piping inside structure
and vent pipe termination 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 filters(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 connections(s) at the furnace to en-
sure it is physically sound, sealed to the furnace casing, and ter-
minates outside the space containing the furnace.
•Inspect electrical wiring, connections, and components for
loose connections.
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.
CAUTION
Do not use ethylene glycol (Prestone II antifreeze
coolant or equivalent). Failure of plastic compo-
nents will occur.
!
!
Upflow Downflow

10
•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 assem-
bly 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. Support should
be sound with not cracks, sagging, gaps, etc. around the base.
•Check furnace for any obvious signs of deterioration.
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 supply-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 on 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.
•Is control switch on gas valve in ON position? (Follow start-
up procedures if you must reset switch to ON position.)
•Check manual reset flame rollout switch located on the burner
box. (See Fig. 3 or 4.) if furnace has experienced high temper-
ature conditions, this switch will shut off the furnace. Reset it
by pushing the button on the switch. If it trips again, shut down
the furnace and call for service. See “Shutting Down Your Fur-
nace”section in this manual.
•Check for obstructions around the vent termination.
If the furnace still fails to operate, call your service representa-
tive.
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 a light-emitting-diode (LED) code display to
aid the installer, service technician, or homeowner while install-
ing or servicing the unit. The LED code can be seen by remov-
ing the main furnace door and viewing the LED through the
view port in the blower access panel.