Frymaster FMCFE Guide

NON-CE &
Frymaster, a member of the Commercial Food Equipment Service Association, recommends
using CFESA Certified Technicians.
24-Hour Service Hotline [phone] APRIL 2005
PRINTED IN THE USA
www.frymaster.com
Email: [email protected]
*8195186*
Master Jet CF Series Atmospheric
Gas Fryers
Service & Parts Manual
Series MJCF, MJCFE, MJCFEC, FMCFE,
FMCFEC, JCFX, KJ3FC, J3F & J65X.

ii
Please read all sections of this manual and retain for future reference.
NOTICE
This appliance is intended for professional use only and is to be operated by qualified
personnel only. A Frymaster Factory Authorized Service Center (FASC) or other qualified
professional should perform installation, maintenance, and repairs. Installation, maintenance,
or repairs by unqualified personnel may void the manufacturer’s warranty.
NOTICE
Drawings and photos used in this manual are intended to illustrate operational, cleaning and
technical procedures and may not conform to onsite management operational procedures.
NOTICE
IF, DURING THE WARRANTY PERIOD, THE CUSTOMER USES A PART FOR THIS ENODIS
EQUIPMENT OTHER THAN AN UNMODIFIED NEW OR RECYCLED PART PURCHASED
DIRECTLY FROM FRYMASTER/DEAN, OR ANY OF ITS AUTHORIZED SERVICE CENTERS,
AND/OR THE PART BEING USED IS MODIFIED FROM ITS ORIGINAL CONFIGURATION, THIS
WARRANTY WILL BE VOID. FURTHER, FRYMASTER/DEAN AND ITS AFFILIATES WILL NOT BE
LIABLE FOR ANY CLAIMS, DAMAGES OR EXPENSES INCURRED BY THE CUSTOMER WHICH
ARISE DIRECTLY OR INDIRECTLY, IN WHOLE OR IN PART, DUE TO THE INSTALLATION OF
ANY MODIFIED PART AND/OR PART RECEIVED FROM AN UNAUTHORIZED SERVICE CENTER.
DANGER
Improper installation, adjustment, maintenance or service, and unauthorized alterations or
modifications can cause property damage, injury, or death. Read the installation, operating and
service instructions thoroughly before installing or servicing this equipment. Only qualified
service personnel may convert this appliance to use a gas other than that for which it was
originally configured.
DANGER
Adequate means must be provided to limit the movement of this appliance without depending
upon the gas line connection. Single fryers equipped with legs must be stabilized by installing
anchor straps. All fryers equipped with casters must be stabilized by installing restraining
chains. If a flexible gas line is used, an additional restraining cable must be connected at all
times when the fryer is in use.
DANGER
The front ledge of the fryer is not a step. Do not stand on the fryer. Serious injury can result
from slips or contact with the hot oil.
DANGER
Do not store or use gasoline or other flammable vapors and liquids in the vicinity of this or any
other cooking appliance.
WARNING
No structural material on the fryer should be altered or removed to accommodate placement of
the fryer under a hood. Questions? Call the Frymaster Service Hotline at 1-800-551-8633.

iii
DANGER
Instructions explaining procedures to be followed MUST be posted in a prominent location in
the event the operator detects a gas leak. This information can be obtained from the local gas
company or gas supplier.
DANGER
The crumb tray in fryers equipped with a filter system must be emptied into a fireproof container
at the end of frying operations each day. Some food particles can spontaneously combust if left
soaking in certain shortening material. Additional information can be obtained in the filtration
manual included with the system.
WARNING
Do not bang fry baskets or other utensils on the fryer’s joiner strip. The strip is present to seal
the joint between the frypot. Banging fry baskets on the strip to dislodge shortening will distort
the strip, adversely affecting its fit. It is designed for a tight fit and should only be removed for
cleaning.
IMPORTANT
Safe and satisfactory operation of Frymaster equipment depends upon its proper installation.
Installation MUST conform with local codes, or in the absence of local codes, to European
Community (CE) Standards.
COMPUTERS
FCC
This device complies with Part 15 of the FCC rules. Operation is subject to the following two conditions:
1) This device may not cause harmful interference, and 2) This device must accept any interference
received, including interference that may cause undesired operation. While this device is a verified Class
A device, it has been shown to meet the Class B limits.
CANADA
This digital apparatus does not exceed the Class A or B limits for radio noise emissions as set out by the
ICES-003 standard of the Canadian Department of Communications.
Cet appareil numerique n’emet pas de bruits radioelectriques depassany les limites de classe A et B
prescrites dans la norme NMB-003 edictee par le Ministre des Communcations du Canada.
DANGER
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.

iv
Master Jet CF Series Atmospheric Gas Fryers
TABLE OF CONTENTS
PAGE #
1.
1.1
1.2
1.3
1.4
1.5
1.6
1.7
1.8
1.8.1
1.8.2
1.8.3
1.8.4
1.8.5
1.8.6
1.8.7
1.8.8
1.8.9
1.8.10
1.8.11
1.8.12
1.9
1.9.1
1.9.2
1.9.3
1.9.4
1.9.5
1.9.6
1.9.7
1.10
1.10.1
1.10.2
1.11
1.12
1.12.1
1.12.2
1.12.3
1.12.4
1.12.5
SERVICE PROCEDURES
Functional Description
Accessing Fryers for Servicing
Cleaning Burner Manifold Gas Pressure
Adjusting Pilot Flame
Cleaning Gas Valve Vent Tube
Adjusting Burner Ceramic Target Spacing and Alignment
Calibrating Thermostat Control
Replacing Fryer Components
Replacing Computer
Replacing Operating Thermostat
Replacing Temperature Probe
Replacing High-Limit Thermostat – Operating Thermostat Controls
Replacing High-Limit Thermostat – Computer Controls
Replacing Heat Mode Indicator Light – Operating Thermostat Controls
Replacing Power/Melt Cycle Switch – Operating Thermostat Controls
Replacing Melt Cycle Timer – Operating Thermostat Controls
Replacing Burner Ceramic Targets
Replacing Gas Valve
Replacing Pilot Assembly or Thermopile
Replacing Frypot
Troubleshooting and Problem Isolation
Pilot/Ignition Failures
Improper Burner Functioning
Improper Temperature Control
Computer Related Problems
Filtration Problems
Leakage Problems
Millivolt Problems
Troubleshooting Guides
Initial Troubleshooting, Millivolt Frying Systems
Initial Troubleshooting, 24VAC Frying Systems
Probe Resistance Chart
Wiring Diagrams
MJCF Millivolt Wiring Diagram, Non-CE
MJCF Millivolt Wiring Diagram, CE
MJCFE 24V Wiring Diagram
MJCFEC 24V Wiring Diagram
FAST-Ready Constant Pilot
1–1
1–1
1–4
1–5
1–6
1–7
1–7
1–8
1–9
1–9
1–10
1–11
1–11
1–12
1–13
1–13
1–14
1–15
1–17
1–17
1–18
1–20
1–20
1–22
1–23
1–24
1–26
1–28
1-28
1–31
1–31
1–33
1–34
1–32
1–35
1–36
1–37
1–38
1–39

v
Master Jet CF Series Atmospheric Gas Fryers
TABLE OF CONTENTS (cont.)
PAGE #
1.12.6
2.
2.1
2.2
2.3
2.3.1
2.3.2
2.4
2.5
2.5.1
2.5.2
2.5.3
2.6
2.7
2.7.1.1
2.7.1.2
2.7.2
2.7.3
2.7.4
2.7.5
2.7.6
2.7.7
2.7.8.1
2.7.8.2
2.7.9
2.8
2.9
A.
A.1
A.1.1
A.1.2
A.1.3
A.1.4
A.1.5
A.1.6
A.1.7
A.2
Filter Magic II Wiring Diagram
PARTSLIST
Accessories
Burner Manifold Components
Cabinetry Components
Fryer Cabinetry
Filter Magic II and Spreader Cabinet Cabinetry
Casters, Legs and Associated Hardware
Component Shield, Filter Box Assemblies and Components
Component Shield Assemblies – No Interface Board
Component Shield Assemblies – With Interface Board
Filter Box Assemblies
Control Panel Assemblies and Related Components
Filtration System Components
Filter Magic II Drain Manifold Components
Euro-Look Drain Manifold Components
Filter Magic II Filter Pan Components – Outer Pan Components
Filter Magic II Filter Pan Components – Inner Pan Components
Oil Return Handle Components – Units Built Prior to April 2001
Oil Return Handle Components – Units Built April 2001 and After
Oil Return Plumbing
Filter Pump and Motor Components
Drain Valves and Related Components
Euro-Look Drain Valves and Related Components
Power Shower Components
Frypot, High-Limit and Probe Components
Wiring Connectors, Pin Terminals and Power Cords
APPENDIX
KJ3FC & J3F Variants – Wiring Diagrams
Computer Wiring Diagram – KJ3FC Fast-Ready
J3F Wiring Diagram – (Fast/Fast-Computer Modified; For Reference Only)
KFC-1 Computer Wiring Diagram – 120V
KFC-1 Computer Wiring Diagram – 220V
KSCF Wiring Diagram w/ Float (CE)
KFC-1 Harness Diagram
Transformer/Filter Box Wiring for FAST Controller
Parts List – KJ3FC Variant
1–40
2–1
2–1
2–3
2–5
2–5
2–7
2–9
2–10
2–10
2–11
2–12
2–13
2–15
2–15
2–17
2–18
2–19
2–21
2–22
2–23
2–24
2–26
2–27
2–28
2–29
2–31
A–1
A–1
A–1
A–2
A–3
A–4
A–5
A–6
A–7
A–8

MASTER JET CF SERIES ATMOSPHERIC GAS FRYERS
CHAPTER 1: SERVICE PROCEDURES
1-1
1.1 Functional Description
Master Jet (MJ) CF Series Atmospheric gas fryers contain a welded stainless steel frypot that is
directly heated by gas flames that are diffused evenly over its lower surface by ceramic targets.
The flames originate from orifices in a U-shaped burner manifold positioned beneath the frypot. The
orifice diameters differ for natural and propane gas as shown in the table below. For altitudes of
2000 feet and greater, contact factory for correct orifice part number.
Gas Inches Millimeters
Natural 0.055 1.4
Propane 0.035 0.9
CF Series Orifice Sizes (0-1999 ft/609 m)
Gas flow to the manifold is regulated by an electromechanical gas valve. MJCF Series gas fryers are
equipped with millivolt gas valves, and MJCFE Series gas fryers are equipped with 24-volt gas
valves. All models use a pilot ignition system.
Pilot Ignition System
The pilot ignition system consists of the pilot orifice, pilot hood, and a thermopile (a thermocouple is
also used in CE units per CE requirements). The pilot serves two purposes. The first is to light the
burner, the second is to heat the thermopile. In operation, the thermopile is in contact with the pilot
flame and generates millivolts. The millivolt output passes through a normally closed high-limit
switch and energizes the gas valve pilot coil, which in turn opens the pilot valve. If the pilot flame is
extinguished, voltage is lost to the gas valve pilot coil and the pilot valve closes.
On MJCFE models, a separate 24-volt circuit,
activated by the fryer On/Off switch,
provides voltage through the thermostat or
controller to the gas valve main coil, which
opens the main valve. The gas valve is
constructed so that the main valve will not
open if the pilot valve is not open. The pilot
flame must be manually lit (either with a
match or with an optional built-in piezo
ignitor) when the fryer is first placed into
operation.
High-Limit
Main Valve Magnet
Pilot Magnet
Thermopile
Pilot
Gas Valve
Operating Thermostat 24VAC Transformer
Line Voltage
ON/OFF Switch
The Pilot System (24V Circuit, Non-CE).

MASTER JET CF SERIES ATMOSPHERIC GAS FRYERS
CHAPTER 1: SERVICE PROCEDURES
1-2
1.1 Functional Description (cont.)
CONTROL OPTIONS
MJCF Series gas fryers may be equipped with thermostat controllers or Computer Magic III.5
computers. KJ3FC variants are equipped with user-supplied or KFC-1 computers.
MJCF fryers equipped with thermostat controls are turned on and off with the gas valve control knob
(an On/Off switch is optional). The temperature is set by means of a knob connected directly to the
frypot-mounted thermostat. MJCFE models come equipped with a rocker switch to turn the fryer on
and off. Units equipped with thermostat controllers have no interface board.
MJCFE Series with Melt-Cycle option: When the melt cycle switch is placed in the ON position, the
fryer stays in the melt cycle mode until the switch is manually placed in the OFF position, even if the
frypot is at setpoint temperature.
Fryers equipped with computers have an interface board located in the component shield behind the
control panel.
INTERFACE BOARDS
The interface board provides the link between the computer and the fryer’s components without
requiring excessive wiring, and allows the computer to execute commands from one central point.
Depending upon the configuration of the fryer, any of three boards may be used. Regardless of the
particular board installed when the fryer was built, P/N 806-3548 is the universal replacement
part (not applicable to user-supplied computers).
NOTES:
1. RELAYS K1 AND K2 ARE FOR BELL CRANK BASKET LIFTS.
THEY ARE NOT PRESENT ON BOARDS 806-5490 (U.S. & NON-
CE EXPORT UNITS W/O BASKET LIFTS) OR 806-7501 (CE UNITS,
WITH OR WITHOUT BASKET LIFTS).
2. RESISTORS R1, R10, AND R15 ARE NOT USED ON ANY OF THE
THREE BOARDS.
3. RESISTORS R11 AND R12 ARE NOT USED ON 806-5490
BOARDS.
INTERFACE BOARDS 806-3548, 806-5490 & 806-7505
1K3
SOUND
R17
R15
R16
2
3
K2 K1
34
52 1
CR13
D8
2000
R9
C1 R10
COMP AC
D7
R4
D5
R2
R3
24VAC
R8
R12
D6
GV
D4
R6
AL 24V
J2
Frymaster
R14
MADE IN U.S.A.
HOT
AC
D9
AC
COM
HOT
J1
R7
R1
R5
COM
COMP
D1
R11
1
1
34
52 1
34
52 1
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15 1
2
3
4
5
6
7
8
9
10
11
12

MASTER JET CF SERIES ATMOSPHERIC GAS FRYERS
CHAPTER 1: SERVICE PROCEDURES
1-3
1.1 Functional Description (cont.)
Test Meter Setting Pins Results
12 VAC Power to Controller 50 VAC Scale 1 and 3 of J2 12-18
24 VAC Power 50 VAC Scale 24 VAC Terminals 22-28
24 VAC Power to Gas Valve 50 VAC Scale 6 on J1 and GROUND 22-28
120 VAC Power 250 VAC Scale 7 and 12 of J1 110-125
Probe Resistance* R x 1000 OHMS 2 and 3 of J1 **
FREQUENTLY USED TESTPOINTS FOR MODELS WITH INTERFACE BOARDS
** Disconnect 15-Pin harness from controller before testing probe circuit.
** See Probe Resistance Chart at end of chapter.
Four LEDs, arranged across the top of the boards and identified in the table below, are provided to
assist in troubleshooting.
GV Indicates 24 VAC to the gas valve
AL Indicates open Drain Safety Switch (if installed)
24V Indicates 24 VAC from transformer
COMP Indicates 12 VAC to computer
MASTER JET SERIES INTERFACE BOARD
LED DIAGNOSTIC LIGHTS
Every board contains one heat relay (K3), and may contain two basket lift relays (K1 and K2). As
shipped from the factory, fryers with bell-crank basket lifts will have relays K1, K2, and K3. All
other factory-original fryers will have boards with only relay K3.
NOTE: The basket lift option is not available on MJCF Series fryers. The above diagnostic
tables are not applicable to user-supplied or KFC-1 computers.
THERMOSTATS AND TEMPERATURE PROBES
MJCF Series fryers equipped with thermostat controls have an adjustable controlling (operating)
thermostat. The temperature at which the thermostat opens and closes is adjusted by changing the
setting of the thermostat with an attached knob. When new, the Fenwal controlling thermostat is
sensitive to one-degree changes in temperature.
CAUTION
Fenwal thermostats are used in a number of Frymaster products. The thermostat for
the MJCF Series is 4 inches long. Do not use 3-inch Fenwal thermostats in MJCF
Series fryers.

MASTER JET CF SERIES ATMOSPHERIC GAS FRYERS
CHAPTER 1: SERVICE PROCEDURES
1-4
1.1 Functional Description (cont.)
MJCFE Series fryers equipped with computers have a temperature probe. In these units, the probe
resistance varies directly with the temperature. That is, as the temperature rises, so does resistance at
a rate of approximately 2 ohms for every 1° (F or C). Circuitry in the computer monitors the probe
resistance and controls burner firing when the resistance exceeds or falls below programmed
temperatures (setpoints). The temperatures are programmed by means of a keypad on the face of the
computer.
All MJCF Series Atmospheric gas fryers are equipped with a high-limit thermostat.In the event
that the fryer fails to properly control the oil temperature, the high-limit thermostat prevents the fryer
from overheating to the flash point. The high-limit thermostat acts as a normally closed power
switch that opens when exposed to temperatures in the range of 415°F to 435°F (213°C to 224°C).
The high-limit thermostat is the same for CE and Non-CE applications. When a replacement high-
limit thermostat is ordered, ensure the kit appropriate for the valve in use is ordered.
1.2 Accessing Fryers for Servicing
DANGER
Moving a fryer filled with oil may cause spilling or splattering of hot liquid. Follow
the draining instructions in the Operator’s manual that shipped with the fryer.
1. Shut off the gas supply to the unit. Unplug the power cord(s). Disconnect the unit from the gas
supply.
2. Remove any attached restraining devices.
3. Relocate the fryer for service accessibility.
4. After servicing is complete, reconnect the unit to the gas supply, reattach restraining devices,
and plug in the electrical cords.

MASTER JET CF SERIES ATMOSPHERIC GAS FRYERS
CHAPTER 1: SERVICE PROCEDURES
1-5
1.3 Checking Burner Manifold Gas Pressure
WARNING
This task should be performed by qualified service personnel only.
1. Ensure that the gas valve knob or button is in the OFF position.
2. Remove the pressure tap plug from the end of the manifold (see illustration below) and connect a
gas pressure-measuring device to the port.
Remove plug to connect a gas
pressure-measuring device to the port.
3. Place the gas valve in the ON position then place the fryer power switch in the ON position
(where applicable). When the burner lights and continues to burn, compare the pressure reading
to that for the corresponding gas in the tables below and on the next page.
Model
Gas Type G20 G25 G31
Pressure
(
mbar
)
120 20-25 37-50
Number
of
Orifices 21 21 21
Manifold
Pressure 7,5 10 14,9
CE Standards for Incoming Gas
Pressures
MJCF/J65 CE
Orifice
Size 1,40 1,40 0,95
1(mbar) = 10,2 mm CE
Air Flow
(
m3
/
H
)
3,62 4,18 2,35

MASTER JET CF SERIES ATMOSPHERIC GAS FRYERS
CHAPTER 1: SERVICE PROCEDURES
1-6
1.3 Checking Burner Manifold Gas Pressure (cont.)
Non-CE Standard
for Incoming Gas Pressures
Gas Minimum Maximum
Natural 6" W.C.
1.49 kPa
14.93 mbar
14" W.C.
3.48 kPa
34.84 mbar
LP 11" W.C.
2.74 kPa
27.37 mbar
14" W.C.
3.48 kPa
34.84 mbar
Gas
Natural
LP 8.25" W.C.
2.0 kPa
20.0 mbar
Pressure
Non-CE Standard
3.5" W.C.
.75 kPa
7.5 mbar
for Burner Manifold Gas Pressures
4. If the measured manifold gas pressure does not match the appropriate pressure in the preceding
tables, remove the cap from the gas valve regulator and adjust to the correct pressure.
Honeywell Valve
(Non-CE Units) Honeywell Valve (CE Units)
Regulator Adjustment Screw Cap
1.4 Adjusting Pilot Flame
1. On non-CE valves, remove the cap covering the pilot adjustment screw. On all valves, turn the
pilot adjustment screw counterclockwise to increase the length of the flame or clockwise to
decrease the length of the flame. Adjust the flame to a length of 1 to 1-½ inches (25 to 38 mm).
Honeywell Valve
(Non-CE Units) Honeywell Valve
(CE Units)
Pilot Adjustment Screw
On Non-CE gas valves, remove this cap to
access Pilot Adjustment Screw.
2. On Non-CE valves, reinstall the pilot adjustment screw cap.

MASTER JET CF SERIES ATMOSPHERIC GAS FRYERS
CHAPTER 1: SERVICE PROCEDURES
1-7
1.5 Cleaning Gas Valve Vent Tube
1. Carefully unscrew the vent tube from the gas valve. NOTE: The vent tube may be straightened
for ease in removal.
2. Pass a piece of ordinary binding wire (.052 inch diameter) or equivalent through the tube to
remove any obstruction.
3. Remove the wire, and then blow through the tube to ensure it is clear.
4. Reinstall tube and bend it so that the opening is pointing downward.
1.6 Adjusting Burner Ceramic Target Spacing and Alignment
DANGER
Drain the frypot or remove the handle from the drain valve before proceeding further.
Proper spacing of the top edge of the burner ceramic targets is ¾-inch (13 mm) from the frypot side
[The rear target should be adjusted to 1-inch (25 mm) from the frypot back]. To adjust target
spacing, bend the brackets to which they are attached away or toward the frypot to the proper
distance. (A length of board of the proper thickness is useful as a gauge to verify spacing and
alignment.)
There should be about 3/4-inch spacing between the top edge of the targets
and the side of the frypot, and 1-inch between the rear target and the frypot
back.
3/4-inch
1-inch

MASTER JET CF SERIES ATMOSPHERIC GAS FRYERS
CHAPTER 1: SERVICE PROCEDURES
1-8
1.7 Calibrating Thermostat Control
1. Fill the frypot to the lower OIL-LEVEL line with oil. If solid shortening is used, it must be
tightly packed into the frypot.
2. Light the pilot. (Refer to Installation and Operation Manual that shipped with the fryer for
detailed lighting instructions.)
3. Insert a good grade thermometer or pyrometer into the frypot, about one inch from the
thermostat.
4. Set the thermostat to 325°F (163°C).
5. Allow the fryer to heat to 325°F (163°C) and cycle on and off three times.
6. With the oil temperature at 325°F (163°C) turn the flexible shaft slowly clockwise until the
burner shuts off. (Turning the shaft counterclockwise causes the temperature to increase and the
burner to light; turning it clockwise causes the temperature to decrease and shut off.)
7. Allow the fryer to sit for a few minutes and then slowly turn the flexible shaft counterclockwise
until the burner lights.
8. Repeat steps 6 and 7 at least three times to ensure an accurate setting is obtained. The thermostat
control is calibrated if the burner lights as the oil cools to 325°F (163°C) – not when the burner
shuts off as the temperature rises.
9. Compare the reading of the pyrometer to the setting on the thermostat plate. The position of the
knob on the thermostat and the reading from the pyrometer should be within 5°F (3°C) of each
other.
10. If not, loosen the setscrew and stop screw securing the thermostat shaft extension to the flexible
shaft. Remove the extension to expose the slot in the end of the flexible shaft. Use a flat-blade
screwdriver to adjust the thermostat.
11. Once the calibration point of 325°F (163°C) is determined, allow the burner to cycle on and off
at least three times to ensure it will light at the calibrated temperature.
12. Carefully replace the thermostat shaft extension, ensuring that the stop screw is pointed straight
up. Tighten the stop screw and locking nut and the setscrew, being careful not to rotate the
flexible shaft.
CAUTION
The thermostat flexible shaft must not be rotated while installing the thermostat
shaft extension!
When handling the thermostat, do not rotate the shaft more than two turns in either
direction. Doing so will cause damage to the thermostat.

MASTER JET CF SERIES ATMOSPHERIC GAS FRYERS
CHAPTER 1: SERVICE PROCEDURES
1-9
1.7 Calibrating Thermostat Control (cont.)
13. Close the fryer control panel and replace the screws in the upper corners.
14. Reinstall the thermostat knob with its pointer aligned with the 325°F (163°C) index mark on the
temperature dial.
15. Reconnect the fryer to the electrical power supply.
1.8 Replacing Fryer Components
1.8.1 Replacing Computer
1. Disconnect the fryer from the electrical
supply.
2. The controller bezel is held in place by
tabs at the top and bottom. Slide the
bezel up to disengage the lower tabs.
Then slide the bezel down to disengage
the upper tabs.
3. Remove the two screws in the upper
corners of the control panel and swing
the panel open from the top, allowing it
to rest on its hinge tabs.
4. Disconnect the wiring harness from the
back of the controller and, if replacing
the harness, disconnect it from the
interface board (arrows).
5. Disconnect the ground wire, and then
remove the controller by lifting it from
the hinge slots in the control panel
frame.
6. Ensure the new computer is properly
configured for the fryer on which it is
installed (i.e., gas or electric, full or
split pot and Celsius or Fahrenheit.
Although identical in appearance,
computers configured for use on one
type of fryer are not directly
interchangeable with those configured
for use on another type.
7. Reverse the procedure to install a new
controller or wiring harness.
If replacing harness, disconnect the harness from
the controller and interface board (arrows).
If replacing controller, disconnect the ground wire
and the 15-pin connector (arrows).

MASTER JET CF SERIES ATMOSPHERIC GAS FRYERS
CHAPTER 1: SERVICE PROCEDURES
1-10
1.8.2 Replacing Operating Thermostat
CAUTION
The thermostat must be calibrated after installation is complete. Refer to Section 1.7
for calibration instructions.
When handling the thermostat, do not rotate the shaft more than two turns in either
direction. Doing so will cause damage to the thermostat.
1. Disconnect the fryer from the electrical supply and drain the frypot.
2. Loosen the setscrew securing the thermostat knob and remove the knob. Remove the screws
from the upper left and right corners of the control panel. The control panel is hinged at the
bottom and will swing open from the top.
3. Disconnect the 9-pin connector and remove the control panel from the fryer by disengaging its
tabs from the hinge slots in the mounting frame.
4. Loosen the setscrews (2) securing the
flexible shaft to the thermostat shaft and
slip the flexible shaft off the thermostat
shaft (arrow).
5. Remove the flexible shaft guide by
removing the two sheet metal screws
securing it to the upper frame.
6. Disconnect the thermostat leads from pin
14 in the 20-pin terminal block and from
the gas valve terminal.
NOTE: If the fryer is configured with a
melt cycle, the thermostat leads will be
connected to the melt cycle timer motor
or PC board rather than to the terminal
block and gas valve. Disconnect the leads
from the motor or PC board if this is the
case.
7. Unscrew the thermostat from the frypot and remove.
8. Apply Loctite PST567 thread sealant or equivalent to the replacement thermostat threads.
9. Reverse steps 1 through 7 to install the replacement.
Remove setscrews (arrow) to remove flexible shaft
from thermostat shaft.

MASTER JET CF SERIES ATMOSPHERIC GAS FRYERS
CHAPTER 1: SERVICE PROCEDURES
1-11
1.8.3 Replacing Temperature Probe
1. Disconnect the fryer from the electrical supply.
2. Drain the frypot.
3. Remove the screws from the upper left and right corners of the control panel. The panel is
hinged at the bottom and will swing open from the top.
4. Unplug the wiring harness from the back of the controller and disconnect the grounding wire
(see Section 1.8.1, Step 4).
5. Remove the controller from the fryer by lifting it from the hinge slots in the control panel frame.
5. Remove the two screws from the base of the interface board mounting-bracket.
6. Disconnect the 12-pin plug from the back of the interface board and lay the board in the left end
of the compartment with all other wires still connected.
7. Remove the 12-volt transformer from the component shield and lay it in the left end of the
compartment with wires still connected.
8. Using a pin-pusher, remove the temperature probe wires (pins 1 and 2) from the 12-pin plug
disconnected in step 7.
9. Unscrew the temperature probe from the frypot and remove.
10. Apply Loctite PST567 thread sealant or equivalent to new probe threads.
11. Reverse steps 1 through 10 to install the replacement probe.
1.8.4 Replacing High-Limit Thermostat – Operating Thermostat Controls
1. Disconnect the fryer from the electrical supply.
2. Drain the frypot.
3. Loosen the setscrew securing the thermostat knob and remove the knob. Remove the screws
from the upper left and right corners of the control panel. The control panel is hinged at the
bottom and will swing open from the top.
4. Disconnect the 9-pin connector and remove the control panel from the fryer by disengaging its
tabs from the hinge slots in the mounting frame.
5. Disconnect the high-limit thermostat leads from the gas valve pilot coil.

MASTER JET CF SERIES ATMOSPHERIC GAS FRYERS
CHAPTER 1: SERVICE PROCEDURES
1-12
1.8.4 Replacing High-Limit Thermostat – Operating Thermostat Controls (cont.)
6. Unscrew the high-limit thermostat from the frypot and remove.
7. Apply Loctite PST567 thread sealant or equivalent to the replacement thermostat threads.
8. Reverse steps 1 through 7 to install the replacement.
1.8.5 Replacing High-Limit Thermostat – Computer Controls
1. Disconnect the fryer from the electrical power supply.
2. Drain the frypot.
3. Remove the screws from the upper left and right corners of the computer panel. The computer is
hinged at the bottom and will swing open from the top.
4. Unplug the wiring harness and disconnect the grounding wire from the controller.
5. Remove the controller from the fryer by lifting it from the hinge slots in the fryer control panel
frame.
6. Remove the two screws from the base of the interface board-mounting bracket.
7. Disconnect the 12-pin plug from the back of the interface board and lay the board in the right end
of the compartment with all other wires still connected.
8. Remove the 12-volt transformer and lay it in the right end of the compartment with wires still
connected.
9. Remove the high-limit thermostat wires from the gas valve pilot coil and pull them up through
the control shield.
10. Unscrew the high-limit thermostat from the frypot and remove.
11. Apply Loctite PST567 thread sealant or equivalent to the replacement thermostat’s threads and
screw it into the frypot.
12. Attach the appropriate terminals (furnished in the replacement thermostat kit) to the thermostat
leads.
13. Reverse steps 1 through 9 to complete installation of the replacement thermostat.

MASTER JET CF SERIES ATMOSPHERIC GAS FRYERS
CHAPTER 1: SERVICE PROCEDURES
1-13
1.8.6 Replacing Heat Mode Indicator Light – Operating Thermostat Controls
1. Disconnect the fryer from the electrical supply.
2. Loosen the setscrew securing the thermostat knob and remove the knob. Remove the screws
from the upper left and right corners of the control panel. The control panel is hinged at the
bottom and will swing open from the top.
3. Disconnect the 9-pin connector and remove the control panel from the fryer by disengaging its
tabs from the hinge slots in the mounting frame.
4. Carefully press the light out from the back of the control panel. Disconnect one wire at a time
and reconnect it to the replacement light until all wires are transferred.
5. Carefully press the light back into the control panel.
6. Reverse steps 1-3 to reassemble the fryer.
1.8.7 Replacing Power/Melt Cycle Switch – Operating Thermostat Controls
NOTE: The Power/Melt-Cycle Switch, P/N 807-1404, has been replaced with a new switch, P/N
807-3498. When ordering the new switch, order Kit 826-1792, which contains the new switch and
wiring instructions. The new switch is wired differently than the old one. Ensure the new switch is
wired properly before operating fryer. Consult P/N 819-5889 (MJCF, MJ45 Switch Replacement
Instructions) for further detail.
1. Disconnect the fryer from the electrical supply.
2. Loosen the setscrew securing the thermostat knob and remove the knob. Remove the screws
from the upper left and right corners of the control panel. The control panel is hinged at the
bottom and will swing open from the top.
3. Disconnect the 9-pin connector and remove the control panel from the fryer by disengaging its
tabs from the hinge slots in the mounting frame.
4. Using a flat-tipped screwdriver, disconnect the chrome bezel from the tabs on the switch and
press the switch out from the front.
5. Carefully press the new switch back into the chrome bezel, ensuring the tabs on the switch
engage the slots in the bezel.
6. Disconnect the wires from the old switch and reconnect to the new switch until all wires have
been transferred (see note at the beginning of this procedure).
7. Reverse steps 1-3 to reassemble the fryer.

MASTER JET CF SERIES ATMOSPHERIC GAS FRYERS
CHAPTER 1: SERVICE PROCEDURES
1-14
1.8.8 Replacing Melt Cycle Timer – Operating Thermostat Controls
The mechanical melt cycle timer is no longer available. A solid-state timer replaces the
mechanical unit. To replace the mechanical melt-cycle timer:
1. Remove all electrical power from the fryer. Unplug fryer and ensure all power switches are off.
2. Access timer by removing the control
panel. Remove timer by removing two
screws that hold it in place. Detach wires.
3. Attach wires to the new timer as follows:
Ground -To number 4 of clip terminals.
24VAC - To wire 28C.
Melt - To wire 29C.
Valve - To thermostat.
4. Bolt new timer into place. Reattach
control panel.
Remove the control panel to reveal the mechanical
timer (arrow). The metal plate that holds the timer-
unit in place is secured with two screws. Remove
the screws, lift out the timer and detach the wires.
The solid-state timer mounted on a metal plate,
bolts into the space previously occupied by the
mechanical timer.

MASTER JET CF SERIES ATMOSPHERIC GAS FRYERS
CHAPTER 1: SERVICE PROCEDURES
1-15
1.8.9 Replacing Burner Ceramic Targets
DANGER
Drain the frypot or remove the handle from the drain valve before proceeding further.
1. Disconnect fryer from electrical and gas supplies.
2. On FMCF fryers, remove square-drain sections as necessary to expose burner.
3. Disconnect the wires from the gas valve terminal block, marking each wire to facilitate
connections.
4. Remove the high-limit thermostat wires from the gas valve pilot coil.
5. Disconnect the pipe union collar at the left side of the gas valve (arrow).
6. Remove front burner shields to access burner assembly.
7. Remove the burner heat shield hanger screws at the front of the burner and remove the heat
shield.
8. Remove the burner hanger screws and lower the front of the main burner. Pull it forward to clear
the rear burner hanger, and then lower the burner to the floor.
9. Raise the front of the fryer enough to slide the burner from under the fryer cabinet.
Disconnect union (arrow) to remove burner manifold assembly.