Frymaster Pro H50-Series Building instructions

Frymaster, a member of the Commercial Food Equipment Service Association, recommends
using CFESA Certified Technicians.
24-Hour Service Hotline [phone] JUNE 2007
*8190001*
H50 Series Gas Fryers
Service and Parts Manual

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.
NOTICE
This appliance is intended for professional use only and is to be operated by qualified
personnel only. A Frymaster/DEAN 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. See Chapter 1 of
this manual for definitions of qualified personnel.
NOTICE
This equipment must be installed in accordance with the appropriate national and local codes of
the country and/or region in which the appliance is installed. See NATIONAL CODE
REQUIREMENTS in Chapter 2 of this manual for specifics.
NOTICE TO U.S. CUSTOMERS
This equipment is to be installed in compliance with the basic plumbing code of the Building
Officials and Code Administrators International, Inc. (BOCA) and the Food Service Sanitation
Manual of the U.S. Food and Drug Administration.
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 TO OWNERS OF UNITS EQUIPPED WITH COMPUTERS
U.S.
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
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
No structural material on the fryer should be altered or removed to accommodate placement of
the fryer under a hood. Questions? Call the Frymaster/Dean Service Hotline at 1-800-551-8633.
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 liquids or vapors in the vicinity of this or any
other appliance.
DANGER
Instructions to be followed in the event the operator smells gas or otherwise detects a gas leak
must be posted in a prominent location. This information can be obtained from the local gas
company or gas supplier.
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.
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.
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 fry vessels. 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.

H50 SERIES GAS FRYERS
TABLE OF CONTENTS
i
CHAPTER 1: Service Procedures
1.1 Functional Description.......................................................................................................1-1
The Electronic Ignition System .........................................................................................1-1
Interface Boards.................................................................................................................1-2
Thermostats........................................................................................................................1-4
1.2 Accessing Fryers for Servicing..........................................................................................1-4
1.3 Cleaning the Gas Valve Vent Tube ...................................................................................1-4
1.4 Checking the Burner Manifold Gas Pressure.....................................................................1-5
1.5 Measuring Flame Current..................................................................................................1-7
1.6 Replacing Fryer Components ............................................................................................1-7
1.6.1 Replacing the Controller or the Controller Wiring Harness...............................1-7
1.6.2 Replacing the Temperature Probe or High-Limit Thermostat............................1-7
1.6.3 Replacing the Interface Board ...........................................................................1-8
1.6.4 Replacing an Ignition Module ............................................................................1-8
1.6.5 Replacing an Ignitor Assembly...........................................................................1-9
1.6.6 Replacing or Cleaning a Combustion Air Blower..............................................1-9
1.6.7 Replacing a Gas Valve......................................................................................1-12
1.6.8 Replacing a Burner Assembly ..........................................................................1-13
1.6.9 Replacing the Frypot.........................................................................................1-14
1.6.10 Replacing Frypot Insulation and/or Upper Burner Rails..................................1-15
1.7 Troubleshooting and Problem Isolation...........................................................................1-20
1.7.1 Ignition Failures................................................................................................1-20
1.7.2 Improper Burner Functioning...........................................................................1-21
1.7.3 Improper Temperature Control.........................................................................1-23
1.7.4 Computer-Related Problems.............................................................................1-24
1.7.5 Filtration Problems............................................................................................1-25
1.7.6 Leakage.............................................................................................................1-28
1.7.7 Basket Lift Malfunctions ..................................................................................1-28
1.7.8 Interpretation of Digital Controller Lights........................................................1-31
1.8 Troubleshooting Guide ....................................................................................................1-31
Probe Resistance Chart....................................................................................................1-38
1.9 Simplified Wiring Diagrams............................................................................................1-39
1.10 Principal Wiring Connections..........................................................................................1-41
1.11 Wiring Diagrams – Main ................................................................................................1-42
1.12 Wiring Diagrams – Transformer Boxes...........................................................................1-48
1.13 Wiring Diagrams – Basket Lifts......................................................................................1-50
1.14 Wiring Diagrams – Filter Boxes......................................................................................1-53
1.15 Wiring Diagrams – Oil Return.........................................................................................1-54

H50 SERIES GAS FRYERS
TABLE OF CONTENTS
ii
CHAPTER 2: Parts List
2.1 Accessories........................................................................................................................2-1
2.2 Basket Lift Assemblies and Component Parts ..................................................................2-2
2.2.1 Bell Crank Basket Lifts......................................................................................2-2
2.2.2 Modular Basket Lifts.......................................................................................... 2-4
2.3 Blower Assemblies and Associated Components.............................................................2-6
2.4 Casters, Legs, and Restraints............................................................................................. 2-7
2.5 Burner Ignition System Components and Associated Hardware......................................2-8
2.6 Component Box Assemblies and Associated Component Parts .......................................2-9
2.7 Controller Assemblies..................................................................................................... 2-10
2.8 Drain Valves, Drain Valve Assemblies, and Associated Parts .......................................2-11
2.8.1 Drain Valves and Drain Extensions ................................................................. 2-11
2.8.2 MJH50 Dual Vat (1-inch) Drain Valve Assemblies ........................................2-12
2.8.3 FMH50 Dual Vat (1-inch) Drain Valve Assemblies........................................2-13
2.8.4 FMH50 Full Vat (1¼-inch) Drain Valve Assembly.........................................2-14
2.8.5 FPH50 Dual Vat (1-inch X 1¼-inch) Valve Assemblies.................................2-15
2.8.6 FPH50 Full Vat (1¼-inch) Valve Assemblies..................................................2-16
2.9 Filtration Systems and Component Parts (Other Than Drain Components)...................2-17
2.9.1 Filter Magic II/Single FootPrint III Filter Pan Assembly ................................2-17
2.9.2 FootPrint III Filter Pan Assembly....................................................................2-18
2.9.3 FootPrint III with Rear Flush Oil Return Plumbing Components, KFC..........2-19
2.9.4 Oil Return Handle Assembly, Filter Magic & Standard FootPrint III.............2-21
2.9.5 Power Shower Assemblies (All Systems)........................................................2-22
2.9.6 Assembly Wand Plumbing (Japan).................................................................. 2-23
2.9.7 Oil Disposal Wand Assembly ..........................................................................2-24
2.10 Frypot Assemblies and Component Parts ....................................................................... 2-24
2.10.1 Replacement Frypots and Frypot Insulation Kits.............................................2-24
2.10.2 Full Vat Frypot Assembly, Component Parts ..................................................2-25
2.10.3 Dual Vat Frypot Assembly, Component Parts................................................. 2-27
2.11 Gas Valves, Gas Lines, and Fittings................................................................................ 2-29
2.12 Probe, Probe Guard, and Thermostat ..............................................................................2-31
2.13 Relays, Transformers, Wiring Assemblies, and Related Parts........................................2-32
2.13.1 Filter Box Components .................................................................................... 2-32
2.13.2 Transformer Box Components.........................................................................2-33
2.14 Wiring Harnesses, Wiring Assemblies, and Plug Assemblies........................................2-35
2.15 Wiring Connectors and Pin Terminals............................................................................2-39

H50 SERIES GAS FRYERS
CHAPTER 1: SERVICE PROCEDURES
1-1
Inside the Ignition Module
TD
Out to
Gas Valve
To Alarm
25 V +
GND
HV
Ignition Wire Flame Sensor
Coil
1.1 Functional Description
H50 Series fryers contain a welded stainless steel frypot that is directly heated by a high efficiency
infrared burner system requiring approximately 43% less energy than conventional burners to cook
the same volume.
Self-contained combustion chambers (referred to as “burners”) are fitted into rails attached to the
sides of the frypot, one on each side. Each combustion chamber is fitted with special ceramic tiles
that are heated by the burning of a forced air/gas mixture. The tiles transfer their heat to the frypot
by means of infrared radiation, providing much more constant and uniform heat dispersion over the
surface of the frypot than do conventional burners. Because less heat is lost to the atmosphere in the
process, compared to “open-burner” designs, less fuel is required to achieve and maintain a given
frypot temperature.
In full vat units, gas flow to both of the burners is regulated by one electromechanical gas valve. In
dual vat units, each burner has its own valve. All fryers in this series are equipped with 24VAC gas
valve systems, and all are configured with electronic ignition.
THE ELECTRONIC IGNITION SYSTEM
An ignition module mounted in the component box or
“shield” (located behind the control panel) is connected to
an ignitor assembly at the burner. The ignition module
performs four important functions: it provides fuse
protection for the 24-volt circuit, provides an ignition
spark, supplies voltage to the gas valve, and proofs the
burner flame. The module contains a 4-second time delay
circuit and a coil that activates the gas valve. Three types
are in use. A closed-box design is used in most fryers, but
in some fryers built for export the module resembles an
interface board. A single dual-spark module is used on
current production full-vat fryers. Two single-spark
modules were used on full-vat fryers built before August
2000. All dual-vat fryers use two single-spark modules.
The ignitor assembly consists of a spark plug, an enrichment tube, and a flame sensor.
At start-up, the power switch is placed in the ON position, supplying approximately 12-volts DC to
the heat control circuitry in the controller or computer and to one side of the heat relay coils on the
interface board. If resistance in the temperature probe indicates the temperature in the frypot is
below 180ºF (82ºC), the current flows through a melt cycle circuit where a timer switch alternately
closes for 6 seconds and opens for 24 seconds. If the temperature is 180ºF (82ºC) or above, the
current flows through a heat circuit, bypassing the timer switch. In either case, ground is supplied
to

1-2
the other leg of the heat relay coils, which then close electronic switches in the 24 VAC circuit to
provide current to the ignition module. Circuitry in the ignition module sends 24 VAC to the gas
valve via a normally closed high-limit switch (and, in fryers with built-in filtration systems, a
normally closed drain safety switch). Simultaneously, the module causes the ignitor to spark for 4
seconds to light the burner. A flame sensor verifies the burner ignition by measuring the flow of
microamps through the flame. If the burner does not light (or is extinguished), current to the
ignition module is cut, the gas valve closes, and the ignition module “locks out” until the power
switch is turned off and then back on. A probe monitors the temperature in the frypot. When the
programmed setpoint temperature is reached, resistance in the probe causes the heat cycle circuitry
in the controller to cut off current flow through the heat relay. This in turn cuts off the 24 VAC to
the ignition module, causing the gas valve to close.
INTERFACE BOARDS
All fryers in this series have an interface board located in the component box located behind the
control panel. The interface board provides a link between the controller/computer and the fryer’s
individual components without requiring excessive wiring, and allows the controller to execute
commands from one central point. The H50 Series of fryers has been in production since 1983.
Consequently, servicers are likely to encounter three different interface board designs. Although the
boards differ slightly in appearance, basic functioning and electrical connections are the same from
one to another. In the earlier design 806-3398 interface board (used between June 1996 and July
1999), the diagnostic LEDs are arrayed in a row across the bottom of the board as shown in the left-
hand illustration below. In later design 806-3398 interface boards (and in the 106-0396 interface
boards that replaced them in current production fryers), the LEDs (labeled D1 though D7) are
scattered around the board as shown in the right-hand illustration. The primary difference between
the earlier design boards and the later design boards is the combining of the separate blower motor
relay (K4) and the heat relays (K1 and K2) into a pair of replaceable relays (K2 and K3) in the latter.
Also, the 106-0386 interface board has an additional fuse located in the upper right hand corner.
Prior to June 1996, a board with replaceable relays very similar in appearance to the 106-0386 board
was used. It is distinguished from the 106-0386 board by the absence of fuses.
NOTE: Although the printing on many boards indicates 2 Amp fuses, 3 Amp fuses (P/N 807-3843)
must be used.
K4
K1 K2
SOUND
1
2
3
GND
GND
V2D
PWR
AD
AS
V2S
GND
V1D
PWR
ALR
V1S
GND GV PWR AL 12V AIR 24V AL PWR GV GND
J2
EARLIER DESIGN INTERFACE BOARD P/N 806-3398
GND
12 6 3 45
J3
3 6 9 12
2 5 8 11
1 4 7 10
J1
3 6 9 12
2 5 8 11
1 4 7 10
15
12963
14
11852
13
10741
BLOWER
MOTOR
RELAY
K3 K5
HEAT
RELAY
HEAT
RELAY
K4
K1
SOUND
1
2
3
GND
GND
V2D
PWR
AD
AS
V2S
GND
GV
PWR
12V AIR
24V
PWR
GND
V1D
PWR
ALR
V1S
GV
GND
J2
LATER DESIGN INTERFACE BOARDS P/N 806-3398 and 106-0386
GND
J3
3 6 9 12
2 5 8 11
1 4 7 10
J1
3 6 9 12
2 5 8 11
1 4 7 10
15
12963
14
11852
13
10741
K2 K3
HEAT
RELAY
AND
BLOWER
MOTOR
RELAY
D1
D2
D3
D4
D6 D7
Blower
Motor
2 Amp
D5
HEAT
RELAY
AND
BLOWER
MOTOR
RELAY
F2 Ignition
2 AMP Module
This Fuse is NOT
present on 806-3398 IFB.

1-3
FREQUENTLY USED TEST POINTS FOR INTERFACE BOARDS 806-3398 AND 106-0386
Meter
Test Setting Pins Results
12VAC Power to Controller 50VACScale 1 and 3 on J3 or J2 12-18
24VAC Power to Right Module 50VAC Scale 8 on J3 and GROUND 22-28
24VAC Power to Left Module (if present) 50VACScale 8 on J1 and GROUND 22-28
120 VAC Power 250VAC Scale 11 on J3 and GROUND 110-125
120 VAC Power to Blowers 250VAC Scale 12 on J3 and GROUND 110-125
24VAC Power to Full- or Right-vat High-Limit 50VACScale 9 on J3 and GROUND 22-28
24VAC Power to Left High-Limit (if present) 50VAC Scale 9 on J1 and GROUND 22-28
Probe Resistance (Full- or Right-vat) *R x 1000 OHMS 2 and 6 on J3 or 13 and 14 on J2 **
Probe Resistance (Left - if present) * R x1000 OHMS 2 and 6 on J1 or 14 and 15 on J2 **
Probe Isolation R x 1000 OHMS 6 on J1 or J3 and GROUND ***
High-Limit Continuity (Full- or Right-vat) R x 1 OHM 9 on J3 and Wire 13C on Gas Valve 0
High-Limit Continuity (Left - if present) R x 1 OHM 9 on J1 and Wire 12C on Gas Valve 0
** Disconnect 15-pin harness from controller before testing probe circuit.
** See Probe Resistance Chart at end of chapter.
*** 5 mega-Ohms or greater.
These standard interface boards are also used in a number of fryer types besides the H50 Series. The
information contained in this section applies to H50 Series applications ONLY.
Earlier design 806-3398 boards (used from June 1996 through July 1999) contain two heat relays
(K1 and K2) that switch 24VAC to the ignition and gas valve circuits when the computer/controller
heat logic circuit calls for heat. Relay K4 switches 120VAC to the blower motor when either K1 or
K2 closes. The relays on these boards are soldered on – if one fails, the whole board must be
replaced.
The later design 806-3398 (and 106-0386 boards that replaced them in current production fryers)
have only two relays. In this design, K2 and K3 are double-pole-double-throw (dpdt) relays that
supply 24VAC to the ignition and gas valve circuits, as well as 120VAC to the blower motor. The
relays on this board plug into sockets. If a relay fails, that relay can be replaced.
The tables below identify the diagnostic LEDs and their meaning.
12V Indicates 12 VAC from transformer
24V Indicates 24 VAC from transformer
GV Indicates 24 VAC to gas valve (left or right)
PWR Indicates 24 VAC to module (left or right)
AL Indicates module lock-out (left or right)
AIR CE and Japanese units only: air switch closed
EARLIER DESIGN INTERFACE BOARD
LED DIAGNOSTIC LIGHTS
D1 24 VAC to left gas valve (dual vat only)
D2 24 VAC to left ignition module
D3 24 VAC from transformer
D4 24 VAC to right ignition module
D5 24 VAC to gas valve (right valve if dual vat)
D6 12 VAC from transformer
D7 CE and Japanese units only: air switch closed
LATER DESIGN INTERFACE BOARD
LED DIAGNOSTIC LIGHTS

1-4
THERMOSTATS
All fryers in the H50 Series have temperature probes located on the front centerline of each frypot.
(Dual-vat frypots have two probes, one in each vat.) In this type thermostat, 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 1º F. Circuitry in the controller 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 controller.
H50 Series fryers are also 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 above 425ºF to 450ºF (218ºC to 232ºC). The different types of thermostats
have different part numbers for CE and Non-CE models, and are not interchangeable.
1.2 Accessing Fryers for Servicing
DANGER
Moving a fryer filled with cooking oil may cause spilling or splattering of the hot
liquid. Drain the fryer before attempting to relocate a fryer for servicing.
1. Shut off the gas supply to the unit. Unplug the power cords. 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.
1.3 Cleaning the Gas Valve Vent Tube
1. Set the fryer power switch and the gas valve to the OFF position.
2. Carefully unscrew the vent tube from the gas valve. NOTE: The vent tube may be straightened
for ease in removal.
3. Pass a piece of ordinary binding wire (.052 inch diameter) through the tube to remove any
obstruction.
4. Remove the wire and blow through the tube to ensure it is clear.
5. Reinstall the tube and bend it so that the opening is pointing downward.

1-5
1.4 Checking the Burner Manifold Gas Pressure
1. On non-CE fryers, ensure that the gas valve knob is in the OFF position.
Honeywell
ON
OFF
2. Remove the pressure tap plug from the gas valve assembly.
Typical Non-CE
Valve Assembly Typical CE Valve Assembly
Pressure Tap Plug
2. Insert the fitting for a gas pressure-measuring device into the pressure tap hole.
3. On non-CE fryers only, place the gas valve in the ON position.
4. Place the fryer power switch in the ON position. When the burner has lit and burned steadily for
at least one minute, compare the gas pressure reading to the pressure for the corresponding gas in
the appropriate table found on the following page. The tables list the burner manifold gas
pressures for each of the gas types that can be used with this equipment.

1-6
Gas Single
Vat Dual Vat
Natural Gas Lacq
(G20) under 20 mbar 77
Natural Gas Gronique *
(G25) under 25 mbar 10 10
Natural Gas Gronique
(G25) under 20 mbar 10 10
Butane/Propane
(G30) at 28/30 or 50 mbar 17 17
Propane
(G31) under 37 or 50 mbar 20 20
CE Standard
Burner Manifold Gas Pressures
for Fryers Manufactured After April 1999
Pressure (mbar)
* Belgian G25 = 7,0 mbar (single or dual)
Gas Single
Vat Dual Vat
Natural Gas Lacq
(G20) under 20 mbar 76,5
Natural Gas Gronigue *
(G25) under 25 mbar 10 9
Natural Gas Gronigue
(G25) under 20 mbar 10 9
Butane
(G30) at 28/30 or 50 mbar 17 16,5
Propane
(G31) under 37 or 50 mbar 20,2 18,5
CE Standard
Burner Manifold Gas Pressures
for Fryers Manufactured Through April 1999
Pressure (mbar)
* Belgian G25 = 7,0 mbar (single) or 6,5 (dual)
Gas Pressure
Natural 3" W.C.
0.73 kPa
Propane 8.25" W.C.
2.5 kPa
Non-CE Standard
Burner Manifold Gas Pressures
5. To adjust the burner gas pressure, remove the cap from the gas valve regulator and adjust to the
correct pressure.
Non-CE
Valve Earlier Model CE Valve Later Model CE Valve
GAS VALVE REGULATOR CAP
6. Place the fryer power switch (and the gas valve in non-CE fryers) in the OFF position. Remove
the fitting from the pressure tap hole and reinstall the pressure tap plug.

1-7
1.5 Measuring Flame Current
When the burner flame is properly adjusted, it will produce a current between 2.5 μA and 3.5 μA.
Flame current is measured by placing a microamp (not milliamp) meter in series with the sensing
wire on the ignitor. This is accomplished as follows:
1. Place the fryer power switch in the OFF position.
2. Disconnect the sensing wire from one of the burner ignitors and connect it to the positive lead of
the meter. Connect the negative lead of the meter to the terminal from which the sensing wire
was removed.
3. Place the fryer power switch in the ON position to light the burners. Wait at least one minute
after the frypot temperature reaches 200°F (93°C) before checking the reading. NOTE: The
closer the unit is to normal operating temperature, the more accurate the reading will be.
1.6 Replacing Fryer Components
1.6.1 Replacing the Controller or the Controller Wiring Harness
1. Disconnect the fryer from the electrical supply.
2. 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.
3. Disconnect the wiring harness from the back of the controller and, if replacing the harness,
disconnect it from the interface board.
4. Disconnect the ground wire from the controller, and remove the controller by lifting it from the
hinge slots in the control panel frame.
5. Reverse the procedure to install a new controller or wiring harness. NOTE: Ensure that the fer-
rite bead (black ring) in the harness is at the controller end.
1.6.2 Replacing the Temperature Probe or High-Limit Thermostat
1. Disconnect the fryer from the electrical supply.
2. Drain cooking oil below the level of the probe or thermostat.
3. Remove the screws from the upper corners of the control panel and swing the panel open from
the top, allowing it to rest on its hinge tabs.
4. Unplug the controller wiring harness from the back of the controller.
5. Remove the controller by lifting it from the hinge slots in the control panel frame.
6. If the fryer has a built-in filtration system, loosen the bolt securing the oil return handle to the oil
return operating rod.

1-8
7. Disconnect the ignition cables from the ignitors by grasping the boots and gently pulling toward
you.
8. Remove the component box mounting screws.
9. Rotate the top of the component box out of the frame and carefully pull it out enough to
disconnect the wiring harness plug(s) from the back of the box.
10. Remove the box and set it aside.
11. Make a note of the location of the existing wires. Using a pin-pusher, disconnect the tempera-
ture probe wires (or high-limit thermostat wires) from the connector plug.
12. Unscrew and remove the temperature probe (or high limit thermostat) from the frypot.
13. Apply Loctite®PST56765 pipe thread sealant or equivalent to the replacement part threads.
14. Screw the replacement part into the frypot and torque to 180 inch-pounds.
15. Connect the wires from the new component to the connector plug, referring to the note made in
step 11.
16. Reverse steps 1 through 9 to complete the procedure.
1.6.3 Replacing the Interface Board
1. Remove the component box per steps 1 through 10 of Section 1.6.2.
2. Unplug the controller wiring harness from the interface board.
3. Disconnect the wires attached to the interface board, marking or making a note of the wires and
terminals to facilitate reconnection.
4. Remove the nuts at each corner of the interface board and pull it from the studs.
5. Reverse the procedure to install the replacement board, being sure to reinstall the spacers behind
the interface board.
1.6.4 Replacing an Ignition Module
1. Disconnect the fryer from the electrical supply.
2. Remove the screws from the upper corners of the control panel and swing the panel open from
the top, allowing it to rest on its hinge tabs.
3. Disconnect the wires from the ignition module, marking or making a note of the wires and
terminals to facilitate reconnection.
4. Remove the four ignition module screws and pull the module from the component box.

1-9
5. Reverse the procedure to install the replacement module.
1.6.5 Replacing an Ignitor Assembly
DANGER
Drain the frypot or remove the handle from the drain valve before proceeding further.
1. Disconnect the fryer from the electrical supply.
2. Disconnect the ignition cable from the ignitor by grasping the boot and gently pulling toward
you.
3. Remove the sheet metal screw securing the ignitor to the mounting plate and pull the ignitor
from the fryer.
4. Reverse the procedure to install the replacement ignitor.
1.6.6 Replacing or Cleaning a Combustion Air Blower
A sheet metal shield or shield assembly prevents inadvertent access to the blower assembly. The
specific design varies depending upon the particular configuration of the fryer and the country for
which manufactured, but in all cases, the shield is attached to the cabinet framing by sheet metal
screws. Remove the screws that secure the shield or shield assembly to the cabinet framing and pull
the shield out of the fryer to expose the combustion air blower assembly.
1. Disconnect the blower wiring harness and remove the blower assembly mounting nuts.
2. Remove the three fasteners that secure the blower motor assembly to the blower housing, and
separate the two components.
Wiring connection
Blower
assembly
mounting
nuts

1-10
Remove these fasteners.
(On black-colored FASCO
blowers there are three
nuts. On silver-colored
KOOLTRONICS blowers
there are three screws.)
3. Wrap the motor with plastic wrap to prevent water from entering it. Spray degreaser or
detergent on the blower wheel and the blower housing. Allow it to soak for five minutes. Rinse
the wheel and housing with hot tap water, then dry with a clean cloth.
Wrap the motor and
wires with plastic wrap
or a plastic bag.
BLOWER HOUSING BLOWER WHEEL
4. Remove the plastic wrap from the blower motor assembly. Reassemble the blower motor
assembly and blower housing. Reinstall the blower assembly in the fryer.
5. Reinstall the blower shield or shield assembly.
6. Light the fryer in accordance with the procedure described in Chapter 3, Section 3.1 of the H50
Series Installation and Operation Manual (P/N 819-5000).
7. After the burners have been lit for at least 90 seconds, observe the flames through the burner
viewing ports located on each side of the combustion air blower.

1-11
The air/gas mixture is properly adjusted when the burner manifold pressure is in accordance with the
applicable table on page 1-6 and the burners display a bright orange-red glow. If a blue flame is
observed, or if there are dark spots on a burner face, the air/gas mixture requires adjustment.
Adjusting Air/Gas Mixture
Non-CE Units and CE Units Built After April 1999
On the side of the blower housing opposite the motor is a plate with one or two locking nuts.
Loosen the nut(s) enough to allow the plate to be moved, then adjust the position of the plate to open
or close the air intake opening until a bright orange-red glow is obtained. Carefully hold the plate in
position and tighten the locking nut(s).
TYPICAL NON-CE BLOWER ASSEMBLY TYPICAL CE BLOWER ASSEMBLY
ON UNITS BUILT AFTER APRIL 1999
Right
Viewing
Port
Left Viewing
Port is Behind
Motor
(NOTE: Blower
shield omitted
for clarity.)

1-12
Adjusting Air/Gas Mixture
CE Units Built Through April 1999
CE units built through April 1999 are equipped with a shield assembly in front of the blowers. An
air shutter plate on the face of the shield assembly regulates the amount of airflow to the blower in-
take. To adjust the shutter plate, loosen the locking screws and slide the shutter to the left or right as
necessary to obtain a bright orange-red glow. Carefully hold the shutter plate in position and tighten
the locking screws.
TYPICAL CE BLOWER SHIELD ASSEMBLY
ON UNITS BUILT THROUGH APRIL 1999
1.6.7 Replacing a Gas Valve
DANGER
Drain the frypot or remove the handle from the drain valve before proceeding further.
1. Disconnect fryer from electrical and gas supplies.
2. Disconnect the wires from the gas valve terminal block, marking each wire to facilitate its
reconnection.
3. Remove the vent tube and the enrichment tube fitting from the valve.
4. Disconnect the flexible gas line(s).
5. Carefully unscrew the valve from the manifold. NOTE: Some models may have the valve
attached to the manifold by means of a pipe union. In such cases, remove the valve by
uncoupling the union.
6. Remove all fittings from the old gas valve and install them on the replacement valve, using
Loctite®PST56765 or equivalent pipe thread sealant.
7. Apply Loctite®PST 56765 or equivalent pipe thread sealant to the threads of the manifold (or
union). Reverse steps 1-5 to install the replacement gas valve.

1-13
1.6.8 Replacing a Burner Assembly
DANGER
Drain the frypot or remove the handle from the drain valve before proceeding further.
1. Disconnect the unit from the electrical and gas supplies.
2. Remove the combustion air blower per the procedure found in Section 1.6.6.
3. Remove the four nuts from the air plenum assembly and pull the assembly straight out toward
you until it clears the burner tubes.
NOTE: On a dual vat fryer, it will be necessary to remove the drain valve handles before the
plenum can be removed.
4. Disconnect the ignition cables from the ignitors by grasping their boots and pulling toward you.
5. Disconnect the gas lines and enrichment tubes from the burner orifices and ignitor assemblies.
6. Remove the four ¼” (6mm) nuts securing the outer front covers to the frypot assembly.
7. Remove the sheet metal screws at the top of the outer front covers and pull the covers straight
out toward you until clear of the mounting studs.
8. Remove the washers and tubular spacers from the mounting studs, then pull the inner covers
straight out toward you until clear of the mounting studs.
9. Grasp the burner firmly and pull it toward you until it clears the burner channels, taking care not
to damage the ceramic tiles in the process.
10. Clean all debris from the burner channels and combustion area.
11. Inspect the upper and lower burner rails for cracked or burned-out welds.
a. If the welds in the lower rail are cracked or burned out, the frypot must be replaced. Refer to
Section 1.6.9 for procedure.
b. If the welds in the upper rail are cracked or burned out, the upper rail must be replaced.
Refer to Section 1.6.10 for procedure.
12. Place a new insulating strip along the top, rear, and bottom edge of the burner and carefully slide
it straight into the rails.
NOTE: Use P/N 826-0931 for full vat frypots and P/N 826-0932 for dual vat frypots.
13. Reverse steps 1 through 9 to reassemble the components.
14. Fill the frypot with oil. Turn the fryer on, turn off or bypass the melt cycle, and operate the unit
for at least 10 minutes.

1-14
15. Examine the burner flame. The color and intensity on both sides should be the same.
16. Use an inspection mirror to check for leaks in areas that cannot be directly observed.
17. If a leak is detected, tighten all the lower insulation retainer nuts, allow the frypot to run for five
additional minutes, and repeat steps 15 and 16.
18. If the leak persists, use a rubber hammer and a small block of wood to tap the corners of the
lower combustion chamber insulation retainers. Repeat steps 15 through 17. Repeat this step
until no leakage is detected.
1.6.9 Replacing the Frypot
1. Drain cooking oil from the frypot.
2. Remove all accessories, e.g., frypot covers, basket lift arms, etc. from the fryer.
4. Disconnect the fryer from gas and electrical supplies.
5. Remove the screws from the topcap above the control panel and lift it up and off the fryer(s).
6. Remove the screws from the upper left and right corners of the control panel. Open the panel,
disconnect the controller wiring harness and ground wire. Remove the controller from the fryer.
7. Disconnect the ignition wires from the ignitor plugs by grasping their boots and pulling toward
you.
8. Remove the screws securing the component box to the frame, and then rotate the top of the box
forward and out of the fryer enough to disconnect the wiring harness connector plug(s) on the
rear of the box. Set the component box aside.
9. Using a pin pusher, remove the temperature probe and high-limit thermostat wires from the
plug(s), marking each wire to facilitate re-assembly.
10. On fryers with built-in filtration, remove the cover from the safety drain switch, disconnect the
wires from the switch, and pull them out of the switch box.
11. On fryers with built-in filtration, remove the section(s) of square drain from the drain valve(s) of
the frypot to be removed.
12. Disconnect the gas lines and enrichment tubes from the burner orifices and ignitor assemblies.
13. Remove the frypot hold down bracket.
14. Remove the screws from the flue cap sides and back and lift it clear of the fryer(s).
15. On units equipped with built-in filtration, disconnect the oil return line(s) from the frypot to be
removed.

1-15
16. Carefully lift the frypot from the fryer cabinet.
17. Remove the drain valve(s), temperature probe(s), high-limit thermostat(s), and ignitor
assemblies. Inspect each of these components carefully and install them in the replacement
frypot if they are in serviceable condition. Use Loctite®PST56765 sealant or equivalent on
component threads.
NOTE: Some servicers, based upon their experience, recommend that probes and thermostats
be replaced whenever a frypot is replaced, but this remains the customer’s decision.
18. Reverse steps 1-16 to reassemble fryer.
19. Perform steps 14 through 18 of Section 1.6.8 to ensure that there are no leaks in the burner insu-
lation.
CAUTION
Before installing the temperature probe, high-limit thermostat, and drain valve on the
replacement frypot, clean their threads and apply Loctite®PST56765 thread sealant
or equivalent.
1.6.10 Replacing Frypot Insulation and/or Upper Burner Rails
NOTE: Replacing the burner rails requires completely tearing down the frypot and installing new
frypot insulation. Refer to the frypot exploded view on page 1-18 for component identification. A
CD containing a PowerPoint presentation detailing the procedure is also available (P/N 819-5805).
1. Remove the frypot per Section 1.6.9.
2. Remove the burner assemblies (1).
3. Remove insulation retainers and blanket insulation (2).
4. Remove the upper oil zone insulation bracket and upper oil zone insulation (3).
5. Remove the plenum (4).
6. Remove the front lower combustion chamber insulation retainer and insulation (5), and the front
lower combustion chamber inner insulation retainer and insulation (6).
NOTE: Full vat units have two-piece insulation retainer and insulation components. Dual vat
units have one-piece components.
7. Remove the upper combustion chamber insulation retainer and insulation (7).
8. Remove the inner upper combustion chamber insulation retainer and insulation (8).
9. Remove the rear lower combustion chamber retainers, back, and insulation (9).
NOTE: Full vat units have two-piece backs and four retainers. Dual vat units have one-piece
backs and two retainers.