Delfield MHCFA24, MHCFA34 Manuel de service
Forced Air Holding Cabinet
Original Instructions
Service Manual
This manual is updated as new information and models are released. Visit our website for the latest manual.
Part Number MHCFA_Service Manual 03/16
Safety Notices
Warning
n
Read this manual thoroughly before operating, installing
or performing maintenance on the equipment. Failure
to follow instructions in this manual can cause property
damage, injury or death.
DANGER
Do not install or operate equipment that has been
misused, abused, neglected, damaged, or altered/
modified from that of original manufactured
specifications.
DANGER
Keep power cord AWAY from HEATED surfaces. DO NOT
immerse power cord or plug in water. DO NOT let power
cord hang over edge of table or counter.
DANGER
To avoid pacemaker malfunction, consult physician or
pacemaker manufacture about effects of microwave
energy on pacemaker.
Warning
n
Authorized Service Representatives are obligated to
follow industry standard safety procedures, including,
but not limited to, local/national regulations for
disconnection / lock out / tag out procedures for all
utilities including electric, gas, water and steam.
Warning
n
Do not use electrical appliances or accessories other
than those supplied by the manufacturer.
Warning
n
Use caution when handling metal surface edges of all
equipment.
Warning
n
This appliance is not intended for use by persons
(including children) with reduced physical, sensory
or mental capabilities, or lack of experience and
knowledge, unless they have been given supervision
concerning use of the appliance by a person responsible
for their safety. Do not allow children to play with this
appliance.
Warning
n
DO NOT use this product near water – for example, near
a kitchen sink, in a wet basement, near a swimming
pool, or similar locations.
NOTE: Proper installation, care and maintenance are
essential for maximum performance and trouble-free
operation of your equipment. Visit our website www.
mtwkitchencare.com for manual updates, translations, or
contact information for service agents in your area.
Warning
n
Do Not Store Or Use Gasoline Or Other Flammable
Vapors Or Liquids In The Vicinity Of This Or Any Other
Appliance. Never use flammable oil soaked cloths or
combustible cleaning solutions, for cleaning.
Warning
n
This product contains chemicals known to the State
of California to cause cancer and/or birth defects or
other reproductive harm. Operation, installation, and
servicing of this product could expose you to airborne
particles of glasswool or ceramic fibers, crystalline
silica, and/or carbon monoxide. Inhalation of airborne
particles of glasswool or ceramic fibers is known to the
State of California to cause cancer. Inhalation of carbon
monoxide is known to the State of California to cause
birth defects or other reproductive harm.
Section 1
General Information
Section 2
Installation
Section 3
Operation
Table of Contents
Model Numbers .................................................................................................................. 5
Serial Number Information ...............................................................................................5
Warranty Information ........................................................................................................ 5
Regulatory Certifications ..................................................................................................5
Location ..............................................................................................................................7
Weight of Equipment .........................................................................................................8
Clearance Requirements ....................................................................................................8
Dimensions ......................................................................................................................... 8
Electrical Service ................................................................................................................ 9
Voltage, Watts, Rated Amperages & Power Cord Chart ............................................................9
Section 4
Maintenance
Section 5
Troubleshooting
Control Panel ....................................................................................................................12
Controls/Programming/Settings ....................................................................................12
Pre-Heat Mode ..................................................................................................................................... 12
Active Heating Mode ......................................................................................................................... 12
Programming Mode ........................................................................................................................... 13
Diagnostic Mode ................................................................................................................................ 13
Temperature View Mode ................................................................................................................. 13
Temperature Service Mode ............................................................................................................ 13
Time Button .......................................................................................................................................... 13
Load New Software Via USB ............................................................................................................13
Cleaning and Sanitizing Procedures ...............................................................................15
General .................................................................................................................................................... 15
Exterior Cleaning ................................................................................................................................. 15
Interior Cleaning .................................................................................................................................. 16
Plastic Tray Cleaning ...........................................................................................................................16
Daily Cleaning Instructions .............................................................................................................. 16
Instructions For Replacing an Air Heater .................................................................................... 18
Instructions For Replacing an Air Heater Probe ....................................................................... 18
Instructions For Replacing a Heater Pad or Pad Heater Probe ............................................ 20
Troubleshooting Chart ....................................................................................................21
Part Number MHCFA_Service Manual 03/16 3
Section 6
Controls
Control Troubleshooting .................................................................................................23
Section 7
ICC Timer Bar and Kitchen Minder
Connections ...................................................................................................................... 25
KM1 Monochrome Unit Testing & Troubleshooting ......................................................28
MHCFA22 Timer Bar Diagram ..........................................................................................30
MHCFA23 Timer Bar Diagram ..........................................................................................31
MHCFA24 Timer Bar Diagram ..........................................................................................32
MHCFA34 Timer Bar Diagram ..........................................................................................34
MHCFA42 Timer Bar Diagram ..........................................................................................35
Section 8
Charts
Zone Diagrams & Heating Element Specifications ........................................................37
System Layout ..................................................................................................................38
I/O Board ........................................................................................................................... 39
I/O Board Connections .....................................................................................................40
Section 9
Wiring Diagrams
Table of Contents (continued)
MHCFA22 - Domestic 2x2.................................................................................................43
MHCFA22EX - Export 2x2 ................................................................................................. 45
MHCFA23 & MHCFA24 - Domestic 2x3 & 2x4 .................................................................47
MHCFA23EX & MHCFA24EX - Export 2x3 & 2x4 .............................................................50
MHCFA34 - Domestic 3x4.................................................................................................54
MHCFA34EX - Export 3x4 ................................................................................................. 59
MHCFA42EX - Export 4x2 ................................................................................................. 64
4 Part Number MHCFA_Service Manual 03/16
Section 1
General Information
Model Numbers
Domestic Models
MHCFA22
MHCFA23
MHCFA24
MHCFA34
Export Item/SKU Export Models
MHCFA22EX MHCFA22
MHCFA23EX MHCFA23
MHCFA24EX MHCFA24
MHCFA34EX MHCFA34
MHCFA42EX MHCFA42
Model Suffix
Control Box Time Bar Sided
Suffix
Primary
BP1 X X X
BP2 X X X
BS1 X X X
BS2 X X X
BP1R X X X
BP2R X X X
BS1R* X X X
BS2R* X X X
BP1A X X X
BP2A X X X
BS1A X X X
BS2A X X X
Secondary
None
R/G Light
NOTE: * Suffixes are not available for MHCFA34 and
MHCFA34EX.
A/N
Single
Dual
Serial Number Information
MHCFA holding cabinet serial and model numbers are
located on the data plate. Data plates are located on the
bottom and the right end of the unit.
Always have the serial number of your unit available
when calling for parts or service.
For ICC time bar and kitchen minder connection questions
and issues call - ICC Tech Division 631-673-5100 or 877-4228788 (North America only).
Warranty Information
Visit http://www.mercoproducts.com/minisite/service/
warranty_info to:
• Register your product for warranty.
• Verify warranty information.
• View and download a copy of your warranty.
Regulatory Certifications
Domestic Models are certified by:
• Underwriters Laboratories Sanitation
• Underwriters Laboratories (UL)
• Underwriters Laboratories of Canada (CUL)
Export Models are certified by:
• Underwriters Laboratories Sanitation
• European Conformity
• Technical Inspection Association
Part Number MHCFA_Service Manual 03/16 5
General Information Section 1
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6 Part Number MHCFA_Service Manual 03/16
Section 2
Installation
DANGER
Installation must comply with all applicable fire and
health codes in your jurisdiction.
DANGER
Legs must be installed and the legs must be screwed in
completely.
DANGER
Use appropriate safety equipment during installation
and servicing.
Warning
n
Only trained and authorized service personnel or store
manager should access the service screens. If changes
to these settings are made incorrectly they will cause
the unit to malfunction.
Location
Warning
n
This equipment must be positioned so that the plug is
accessible unless other means for disconnection from
the power supply (e.g., circuit breaker or disconnect
switch) is provided.
Warning
n
Adequate means must be provided to limit the
movement of this appliance without depending on or
transmitting stress to the electrical conduit or gas lines.
Warning
n
To avoid instability the installation area must be capable
of supporting the combined weight of the equipment
and product. Additionally the equipment must be level
side to side and front to back.
Warning
n
This equipment is intended for indoor use only. Do not
install or operate this equipment in outdoor areas.
Caution
,
Do not position the air intake vent near steam or heat
exhaust of another appliance.
The location selected for the equipment must meet the
following criteria. If any of these criteria are not met, select
another location.
• Holding cabinets are intended for indoor use only.
• The location MUST be level, stable and capable of
supporting the weight of the equipment.
• The location MUST be free from and clear of
combustible materials.
• Equipment MUST be level both front to back and side to
side.
• Position the equipment so it will not tip or slide.
• Recommended air temperature is 41° - 86°F (5° - 30°C) .
• Proper air supply for ventilation is REQUIRED AND
CRITICAL for safe and efficient operation. Refer to
Clearance Requirements chart on page 8.
• Do not obstruct the flow of ventilation air. Make sure the
air vents of the equipment are not blocked.
Part Number MHCFA_Service Manual 03/16 7
Installation Section 2
Weight of Equipment
Domestic Model Export Item/SKU Weight
MHCFA22 MHCFA22EX 40lbs/18kg
MHCFA23 MHCFA23EX 65lbs/29kg
MHCFA24 MHCFA24EX 85lbs/39kg
MHCFA34 MHCFA34EX 125lbs/57kg
MHCFA42EX 85lbs/39kg
Clearance Requirements
DANGER
Minimum clearance requirements are the same for
noncombustible locations as for combustible locations.
The flooring under the appliance must be made of a
noncombustible material.
DANGER
Risk of fire/shock. All minimum clearances must be
maintained. Do not obstruct vents or openings.
Sides/Back
1.0” (25mm)
Dimensions
Domestic Model,
Export Item/SKU
MHCFA22,
MHCFA22EX
MHCFA23,
MHCFA23EX
MHCFA24,
MHCFA24EX
MHCFA34,
MHCFA34EX
MHCFA42EX 19.56”
Length Depth Height
19.56”
(497mm)
29.57”
(751mm)
36.45”
(926mm)
36.45”
(926mm)
(497mm)
12.31”
(313mm)
12.31”
(313mm)
12.31”
(313mm)
12.31”
(313mm)
12.31”
(313mm)
11.24”
(285mm)
11.24”
(285mm)
11.24”
(285mm)
15.70”
(399mm)
20.32”
(516mm)
8 Part Number MHCFA_Service Manual 03/16
Section 2 Installation
Electrical Service
VOLTAGE, WATTS, RATED AMPERAGES & POWER CORD
CHART
DANGER
Check all wiring connections, including factory
terminals, before operation. Connections can become
loose during shipment and installation.
All electrical work, including wire routing and grounding,
must conform to local, state and national electrical codes.
The following precautions must be observed:
• The equipment must be grounded.
• A separate fuse/circuit breaker must be provided for
DANGER
Copper wire suitable for at least 167°F (75°C) must be
used for power connections.
each unit.
• A qualified electrician must determine proper wire size
dependent upon location, materials used and length
of run (minimum circuit ampacity can be used to help
Warning
n
This appliance must be grounded and all field wiring
must conform to all applicable local and national
codes. Refer to rating plate for proper voltage. It is the
responsibility of the end user to provide the disconnect
means to satisfy the authority having jurisdiction.
select the wire size).
• The maximum allowable voltage variation is ±10% of
the rated voltage at equipment start-up (when the
electrical load is highest).
• Check all green ground screws, cables and wire
connections to verify they are tight before start-up.
Units with plugs are supplied with approximately 9ft cords,
maximum 10ft.
Domestic Model Voltage, Cycle, Phase Watts Amps Plug
MHCFA22 120, 60, 1 1920 16.0 5-20P
MHCFA23
MHCFA24
MHCFA34
208-230, 60, 1
208-230, 60, 1
208, 60, 1
3174 13.8 6-20P
3680 16.0 6-20P
3120 15.0 6-20P
Export Item/SKU Voltage, Cycle, Phase Watts Amps Plug
MHCFA22EX 200-240, 50/60, 1 2472 9.9-10.3 Varies per destination
MHCFA23EX 200-240, 50/60, 1 2856 11.4-11.9 Varies per destination
MHCFA24EX 200-240, 50/60, 1 2784 9.8-11.6
MHCFA34EX 200-240, 50/60, 1 3072 10.1-12.8
MHCFA42EX 200-240, 50/60, 1 2784 9.8-11.6
16A pin/sleeve
(IEC-60309 16A, 3-pin plug)
16A pin/sleeve
(IEC-60309 16A, 3-pin plug)
16A pin/sleeve
(IEC-60309 16A, 3-pin plug)
Part Number MHCFA_Service Manual 03/16 9
Installation Section 2
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10 Part Number MHCFA_Service Manual 03/16
Section 3
Operation
DANGER
The on-site supervisor is responsible for ensuring that
operators are made aware of the inherent dangers of
operating this equipment.
DANGER
Do not operate any appliance with a damaged cord
or plug. All repairs must be performed by a qualified
service company.
DANGER
Never stand on the unit! They are not designed to
hold the weight of an adult, and may collapse or tip if
misused in this manner.
Warning
n
Do not contact moving parts.
Warning
n
All covers and access panels must be in place and
properly secured, before operating this equipment.
Warning
n
Liquids such as water, coffee, or tea can be overheated
beyond the boiling point without appearing to be
boiling due to surface tension of the liquid. Visible
bubbling or boiling when the container is removed from
the microwave oven is not always present. THIS COULD
RESULT IN VERY HOT LIQUIDS SUDDENLY BOILING OVER
WHEN A SPOON OR OTHER UTENSIL IS INSERTED INTO
THE LIQUID. To reduce the risk of injury to persons: Do
not overheat the liquid. Stir the liquid both before and
halfway through heating it.
Warning
n
DO NOT use the cavity for storage. DO NOT leave paper
products, cooking utensils, or food in the cavity when
not in use.
Caution
,
Do not block the supply and return air grills or the air
space around the air grills. Keep plastic wrappings,
paper, labels, etc. from being airborne and lodging in
the grills. Failure to keep the air grills clear will result in
unsatisfactory operation of the system.
Caution
,
Some products such as whole eggs or sealed containers
– for example, closed glass jars – are able to explode
and SHOULD NOT be HEATED in this oven. Pressure may
build up and erupt. Pierce yolk with fork or knife before
cooking. Pierce skin of potatoes, tomatoes, and similar
foods before cooking with microwave energy. When
skin is pierced, steam escapes evenly.
Caution
,
DO NOT cover racks or any other part of the oven with
metal foil. Airflow restriction will cause overheating of
the oven.
Warning
n
Do not heat sealed containers or plastic bags in oven.
Food or liquid could expand quickly and cause container
or bag to break. Pierce or open container or bag before
heating.
Warning
n
Racks, utensils, rack guides, and oven surfaces may
become hot during or after use. Use utensils or
protective clothing, like pan grips or dry oven mitts,
when necessary to avoid burns.
Part Number MHCFA_Service Manual 03/16 11
Operation Section 3
Control Panel
Left Display
Time Button
(nonfunctional)
Temperature
Button
Power Button
Right
Display
Program
Button
Day Part Button
Up Button
Enter Button
Cancel Button
Down Button
Controls/Programming/Settings
The Merco Holding Cabinet has been designed to afford
foodservice operators the ability to cook menu components
in advance and then gently store that product in the
holding bins until an order is received. Once that order has
been placed, the crew can assemble the order using hot
and fresh menu components from the holding bins. This
allows for operators to serve to order, helping increase
speed of service while maintaining high product quality
standards.
The holding bin controller is, at all times, operating in one
of the following modes. The indents indicate the submodes. Sub-modes are defined based on the navigation
to the mode. I.e., to get to diagnostic mode you must be in
active heating mode then enter programming mode.
• Pre-Heat Mode
• Active Heating Mode
- Programming Mode
» Diagnostic Mode
- Temperature View Mode
» Service Temperature Mode
PREHEAT MODE
The displays shall scroll the message Pre-Heating
repeatedly during pre-heat mode. The LED corresponding
to the active Day Part menu configuration will be on. Once
a heater has reached 180°F (82°C), it will be regulated to
the set point. The PRE-HEAT mode will be terminated when
all of the heaters have reached 180°F (82°C) OR 15 minutes
have passed.
During Pre-Heat mode, all button presses will be ignored
except the check mark button. If the check mark button
is pressed and held for (3) seconds, the displays will scroll
the message, Cancel Pre-Heat? If the check mark button
is pressed again, the unit will Cancel the Pre-Heat mode
and enter Active Heating Mode. If the cancel (X) button is
pressed, the unit shall return to Pre-Heat Mode.
ACTIVE HEATING MODE
This is the active heating mode of operation. In active
heating mode the displays will be blank and the day part
LED light will be ON.
Typical Operator Actions
Action Instructions
Turn Unit On Push Power button.
Load bin with
product
Empty bin Pull out tray and remove product.
Pull out tray, load product and reinsert
tray.
Reinsert tray.
When the unit is first powered ON, the software version
will scroll across the display. It will then begin to preheat.
Allow it to preheat for 15 minutes, the display will scroll
Preheating.
During active heating mode, press enter to scroll the
software version on the display.
12 Part Number MHCFA_Service Manual 03/16
Section 3 Operation
PROGRAMMING MODE
Press the program button to enter the programming mode.
Zone and temperature will display. The zone will flash,
press the up or down button to reach the desired zone.
Press the day part button until the desired day part LED is
ON. Press the temperature button and both the zone and
temperature will flash. Press the up or down button to reach
the desired temperature. The program button LED light will
flash, indicating a program change has occurred. Press enter
or the temperature button to return to the zone selection,
the zone will flash. Press the program button to exit.
DIAGNOSTIC MODE
From Programming mode, press the program button and
hold for 3 seconds to enter Diagnostic Mode.
The software shall track the state of each thermocouple and
the state of the thermocouple reading compared to the set
point.
If the software finds an error, it will begin to time it. When
the timer reaches 15 minutes, an error code(s) will display
(flash) on the screen. This shall continue indefinitely.
Turning Off and On a unit will clear all TC State Display flags
and reset all TC temp timer’s to 0.
TC Display Codes
Left Display Right Display
ZaEr b_cd
a b c d
Zone Location
with Error
1
2
3
4
5
6
7
8
Section of
Zone with
Error
U=Upper
L=Lower
Thermocouple
State
0 = Ok
1 = Shorted
2 = Open
Thermocouple
reading compared
to Set point
0 = Within Range
1 = Below Range
2 = Above Range
TEMPERATURE VIEW MODE
Enter the temperature view mode by pressing the
temperature button. The average temperature in the first
zone will be displayed. Press the up or down button to scroll
through zones. Zones progress from left to right, top to
bottom. Press the temperature button or the cancel button
to exit.
TEMPERATURE SERVICE MODE
Press the temperature button or when already in the
temperature view mode press and the hold temperature
button to display the actual thermocouple temperature.
This is called the temperature service mode. Press the up
or down button to scroll through zones. U stands for upper,
L for lower. Press the temperature button or the cancel
button to exit.
During temperature service mode if the DOWN button
is held for 3 seconds the temperature display shall
be replaced with the word OFF, and the zone shall be
considered OFF. If a zone is considered OFF, the triac
outputs shall be set to off regardless of the thermocouple
feedback for that zone. No alarms shall be initiated for a
zone that is off.
TIME BUTTON
The time button has no function currently. Time will be
displayed on the Timer Bar.
LOAD NEW SOFTWARE VIA USB
Firmware file must be loaded onto the top level of USB
instead of in a folder.
While the unit is OFF, insert the new software USB into the
port. Turn the unit ON by pushing the power button. The
unit will detect the software and begin installation. The
display will scroll Updating Firmware, then Preheating.
When Preheating is scrolling it is clear to remove the USB.
USB Port
Part Number MHCFA_Service Manual 03/16 13
Operation Section 3
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14 Part Number MHCFA_Service Manual 03/16
Section 4
Maintenance
DANGER
All utility connections and fixtures must be maintained
in accordance with Local and national codes.
DANGER
It is the responsibility of the equipment owner to
perform a Personal Protective Equipment Hazard
Assessment to ensure adequate protection during
maintenance procedures.
DANGER
Failure to disconnect the power at the main power
supply disconnect could result in serious injury or death.
The power switch DOES NOT disconnect all incoming
power.
DANGER
Always discharge the ht capacitors before working on
the oven using a suitably insulated 10mo resistor.
DANGER
Disconnect electric power at the main power disconnect
for all equipment being serviced. Observe correct
polarity of incoming line voltage. Incorrect polarity can
lead to erratic operation.
Cleaning and Sanitizing Procedures
GENERAL
You are responsible for maintaining the equipment
in accordance with the instructions in this manual.
Maintenance procedures are not covered by the warranty.
Maintenance Daily After Prolonged
Shutdown
Exterior X X X
Interior X X X
Holding Bin, Bin Lid
& Jet Plate
Plastic Tray X X X
EXTERIOR CLEANING
Never use a high-pressure water jet for cleaning or hose
down or flood interior or exterior of units with water. Do
not use power cleaning equipment, steel wool, scrapers
or wire brushes on stainless steel or painted surfaces.
Never use an acid based cleaning solution on exterior
panels! Many food products have an acidic content,
which can deteriorate the finish. Be sure to clean the
stainless steel surfaces of ALL food products.
X X X
Warning
n
Caution
,
At Start-Up
Warning
n
When using cleaning fluids or chemicals, rubber gloves
and eye protection (and/or face shield) must be worn.
Caution
,
Maintenance and servicing work other than cleaning as
described in this manual must be done by an authorized
service personnel.
Part Number MHCFA_Service Manual 03/16 15
The stainless steel outer case requires nothing more than
a daily wiping with a damp cloth. If, however, an excessive
amount of food particles/grease are allowed to collect, a
non-abrasive cleaner (hot sudsy water) may be used. Wipe
dry with a clean, soft cloth.
Always rub with the “grain” of the stainless steel to avoid
marring the finish. Never use steel wool or abrasive pads
for cleaning. Never use chlorinated, citrus based or abrasive
cleaners.
Stainless steel exterior panels have a clear coating that
is stain resistant and easy to clean. Products containing
abrasives will damage the coating and scratch the panels.
Daily cleaning may be followed by an application of
stainless steel cleaner which will eliminate water spotting
and fingerprints. Early signs of stainless steel breakdown
are small pits and cracks. If this has begun, clean thoroughly
and start to apply stainless steel cleaners in attempt to
restore the steel.
Maintenance Section 4
INTERIOR CLEANING
Caution
,
Do not use caustic cleaners on any part of the oven or
oven cavity . Use mild, non abrasive soaps or detergents,
applied with a sponge or soft cloth. Never use sharp
implements or harsh abrasives on any part of the oven.
The product holding bin, bin lid and jet plate may be
cleaned via dishwasher or with warm soapy water. Care
must be taken to prevent water or cleaning compounds
from getting on internal parts, especially the switches on
the control panel.
PLASTIC TRAY CLEANING
Caution
,
Environmental stress cracking can occur, proper dilution
and rinsing per detergent manufacturers’ directions are
mandatory.
Food-approved detergents can be used if they are diluted
per manufacturers’ directions and adequately rinsed
away prior to high temp drying cycle. Basic alcohols such
as isopropyl are acceptable for hard-to-remove stains.
Otherwise, do not use organic solvents.
DAILY CLEANING INSTRUCTIONS
Unit must be cool to touch and disconnected from
power source.
1. Wipe the stainless steel outer case with a damp cloth,
rubbing with the grain of the steel. If an excessive
amount of food particles/grease has collected, hot
sudsy water (non-abrasive) may be used.
2. Remove bins.
16 Part Number MHCFA_Service Manual 03/16
Section 4 Maintenance
3. Twist each jet plate assembly lever counter clockwise
into the horizontal unlocked position.
4. Remove jet plate assemblies.
7. Reinstall the cleaned jet plate assemblies.
8. Twist each jet plate assembly lever clockwise into the
vertical locked position.
5. The product holding bins, bin lids and jet plates may be
cleaned via dishwasher or with warm soapy water.
6. Wipe the interior bottom with a damp cloth. If,
however, an excessive amount of food particles/grease
has collected, hot sudsy water (non-abrasive) may be
used.
9. Reinstall the cleaned bins.
10. Plug the unit in.
Part Number MHCFA_Service Manual 03/16 17
Maintenance Section 4
INSTRUCTIONS FOR REPLACING AN AIR HEATER
1. Remove end panel.
2. Disconnect heater hot wire from I/O board and neutral
wire from terminal block.
3. Remove the fasteners securing the air heater to the
chassis.
4. Install new air heater with fasteners.
5. Reconnect electrical and reinstall end panel.
INSTRUCTIONS FOR REPLACING AN AIR HEATER
PROBE
Air heater probes are located in the panel above the zone.
Top Zone Air Heater Probe Replacement
1. Remove the unit top.
2. Remove the insulation.
3. Remove probe, it will be thoroughly taped in place.
4. Tape a new probe in it’s place and put the machine
back together.
Lower Zone Air Heater Probe Replacement
These air heater probes are taped in the aluminum plate above
the zone.
1. Remove the Timer Bar above the zone.
2. Remove center divider above the zone via two screws
(US Models).
3. Remove both end clips above the zone via two screws.
4. Remove end panels.
5. From each side remove screws holding in aluminum
plate above zone.
18 Part Number MHCFA_Service Manual 03/16
Section 4 Maintenance
6. From both sides unplug heaters and probes associated
with aluminum plate above zone. Hot wires are
plugged into the I/O board and neutral wires are
connected to the terminal block.
7. Raise aluminum plate and insulation to gain access to
air heater probe below.
8. Remove and replace air heater probe.
9. Put unit back together.
Part Number MHCFA_Service Manual 03/16 19
Maintenance Section 4
INSTRUCTIONS FOR REPLACING A HEATER PAD OR
PAD HEATER PROBE
Pad heater probes are located in the pad heater assembly.
1. Remove the Timer Bar that is in front of the pad heater.
It will be below the zone.
2. Remove jet plates above pad heater.
6. From each side remove screws holding in aluminum
plates.
7. From both sides unplug heaters and probes associated
with the heater pad. Hot wires are plugged into the I/O
board and neutral wires are connected to the terminal
block.
3. Remove center divider above heater pad via two screws
(US Models).
4. Remove both end clips above heater pad via two
screws.
5. Remove end panels.
8. Pull the aluminum plate out carefully.
9. Heater Probe Replacement
Flip the aluminum plate over. Peel the probe out of the
heater pad. The probe has brown insulation. Tape a new
probe in it’s place
10. Heater Pad Replacement
Flip the aluminum plate over. Peel the heater pad off
and stick a new one on.
11. Put the machine back together.
20 Part Number MHCFA_Service Manual 03/16
Section 5
Troubleshooting
Troubleshooting Chart
Problem Cause Correction
Cabinet not
running
Cabinet
temperature is too
high
Cabinet
temperature is too
low
Fuse blown or circuit breaker tripped. Replace fuse or reset circuit breaker.
Power cord unplugged. Plug in power cord.
Thermostat set too high. Set thermostat to lower temperature.
Main power switch turned off. Turn main power switch on.
Thermostat set too high. Set thermostat to lower temperature.
Poor air circulation in cabinet. Re-arrange product to allow proper air circulation.
Exterior thermometer is out of calibration. Re-calibrate thermometer.
Jet plate out of unit. Reinstall jet plate.
Pans out of unit. Reinstall pans in unit.
Part Number MHCFA_Service Manual 03/16 21
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