DEAN SM220, SM35GM Service Manual

Dean Millivolt Gas Fryers

Service & Parts Manual

Super Runner and Super Marathon Series

NON-CE &

Dean, a member of the Commercial Food Equipment Service Association, recommends using CFESA Certified Technicians.

24-Hour Service Hotline

1-800-551-8633

www.frymaster.com

Email: service@frymaster.com

*8195948*

NOVEMBER 2005

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 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.

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.

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 SERVIC E CENTERS,

AND/OR THE PART BEING USED IS MODIFIED FROM ITS ORIGINAL CONFIGURATION, THIS

WARRANTY WILL BE VOID. FURTHER, FRYMASTER DEAN AND ITS AFFILIAT ES 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.

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

No structural material on the fryer should be altered or removed to accommodate placement of

the fryer under a hood. Questions? Call the Dean Service Hotline at 1-800-551-8633.

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 Dean equipment depends upon its proper installation.

Installation MUST conform with local codes, or in the absence of local codes, to European

Community (CE) Standards.

iii

Dean Millivolt Gas Fryers

Service and Parts Manual

TABLE OF CONTENTS

Page #

1. SERVICE PROCEDURES 1-1

1.1 Functional Description 1-1

1.2 Accessing Fryers for Servicing 1-3

1.3 Cleaning the Gas Valve Vent Tube 1-3

1.4 Calibrating the Operating Thermostat 1-4

1.5 Check Burner Manifold Pressure 1-5

1.6 Adjusting the Pilot Flame 1-6

1.7 Replacing Fryer Components 1-6

1.7.1 Replacing the Operating Thermostat 1-6

1.7.2 Replacing the High-Limit Thermostat 1-8

1.7.3 Replacing the Gas Valve 1-8

1.7.4 Replacing the Frypot 1-8

1.8 Troubleshooting and Problem Isolation 1-9

1.8.1 Pilot Failures 1-9

1.8.2 Improper Burner Functioning 1-12

1.8.3 Improper Temperature Control 1-12

1.8.4 Filtration Problems 1-13

1.8.5 Leaking 1-14

1.9 Wiring Diagrams 1-15

1.9.1 Current Production Units with Honeywell Gas Valve (Non-CE) 1-15

1.9.2 Current Production Units with Honeywell Gas Valve (CE) 1-16

1.9.3 Current Production Units with Robertshaw Gas Valve (After May, 2002) 1-17

1.9.4 UFF Filtration Wiring Diagram 1-18

Dean Millivolt Gas Fryers

Service and Parts Manual

TABLE OF CONTENTS (CONT.)

Page #

2. PARTS LIST 2-1

2.1 Cabinetry Components, Single Fryers 2-1

2.2 Cabinetry Components, Multi-Battery Systems 2-4

2.3 Component Box Components and Related Components (Non-CE and CE) 2-6

2.4 Frypot and Burner System Components 2-8

2.4.1 SM220 and SM20/20/~ Systems 2-8

2.4.2 SR Series, SM35G, SM40G and SM50G Systems 2-10

2.4.3 SM60G and SM80G Systems 2-13

2.5 Oil Drain Manifold, Drain Flush and Drain Valve Components 2-16

2.6 Oil Return Manifold Components 2-20

2.7 Oil Return and Oil Flush Components 2-23

2.8 Under Fryer Filter (UFF) Components 2-27

2.8.1 SM50 and SM60 Series Fryers (Except IHOP) 2-27

2.8.2 SM50 Series Fryers, IHOP UFF 50 with Filter Leaf 2-28

2.8.3 SM80 Series Fryers 2-29

2.9 Single Under Fryer Filter (SUFF) Components 2-30

2.9.1 SM50 Series Fryers 2-30

2.9.2 SM60 and SM80 Series Fryers 2-31

)

DEAN MILLIVOLT GAS FRYERS

CHAPTER 1: SERVICE PROCEDURES

1.1 Functional Description

Dean Super Runner and Super Marathon Series fryers are millivolt fryers, which require no electricity to operate (systems with built-in filtration and/or other accessories will require electric power). Dean millivolt fryers contain a welded steel frypot (stainless or cold-rolled) that is heated by gas flames diffused evenly through tubes built into the frypot. The number of tubes varies from three to five, according to the fryer model and size.

Flames originate from orifices in a burner manifold positioned beneath cast-iron burners. The burners are positioned in the tube openings, at the front of the frypot. Diffusers within each tube distribute the flame evenly throughout the tube. The diameter of the orifices differs for natural (CE:G20/G25) and LP (CE:G31) gas as indicated in the accompanying table.

NON-CE (Altitudes of 2000 feet or less

MODEL

SM20GM 50

INPUT

(BTU)

GAS

TYPE

NAT

ORIFICE

(INCH)

2.18(#44)

1.40(#54)

ORIFICE

PART NO.

810-2050 810-2324

QTY

2 2

EQUIPMENT

PRESSURE

MBAR INCH W.C.

27.5

SM 35 (40) GM

SR 42GM

SR 52 GM SM 50 GM

SR 62 GM SM 60 GM

SM 80 GM 165

MODEL

SM20GM

SM 35 (40) GM

SR 42GM

SR 52 GM SM 50 GM

SR 62 GM SM 60 GM

105

120

150

NAT

2.80(#35)

1.70(#51)

2.53(#39)

1.51(#53)

2.53(#39)

1.51(#53)

2.58(#38)

1.61(#52)

810-2140 810-2064

810-2048 810-2059

810-2062 810-2063

CE ONLY (Altitudes of 2000 feet or less

INPUT

(kW)

37,5

GAS

TYPE

G20 G25 G31

ORIFICE

(INCH)

2,40 2,40 1,51

ORIFICE

PART NO.

810-2060 810-2060 810-2059

3 3

4 4

5 5

QTY/

COLOR

2/BLUE 2/BLUE

2/RED

3/BLUE 3/BLUE

3/RED

4/BLUE 4/BLUE

4/RED

5/BLUE 5/BLUE

5/RED

27.5

EQUIPMENT

PRESSURE

MBAR INCH W.C.

10,0 15,0 27,0

4,0 6,0

10,8

4,0 6,0

10,8

4,0 6,0

10,8

4,0 6,0

10,8

SM 80 GM 37,5

G20 G25 G31

2,40 2,40 1,51

810-2060 810-2060 810-2059

5/BLUE 5/BLUE

5/RED

10,0 15,0 27,0

4,0 6,0

10,8

1-1

1.1 Functional Description (cont.)

An electromechanical millivolt gas valve regulates gas flow to the burner manifold. Dean millivolt fryers use a pilot ignition system to control burner firing.

High-Limit

Thermopile

Operating

Thermostat

Gas Valve

Pilot

Pilot Magnet

Main Valve Magnet

Functional diagram of a typical millivolt system.

Pilot Ignition System

The pilot ignition system is made up of the pilot orifice, pilot hood, and a thermopile or thermocouple. The pilot serves two purposes: lighting the burner and heating the thermopile/ thermocouple. In operation, the thermopile/thermocouple 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.

Thermostats

Dean millivolt fryers are equipped with adjustable operating thermostats. The tem p erature at which the thermostat opens and closes is adjusted by turning a knob.

Dean millivolt 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 410ºF (210°C) for CE fryers and 435-450ºF (224-232°C) for non-CE fryers. Once opened, the high limit must be manually reset before operating the fryer.

1-2

1.2 Accessing Fryers for Servicing

DANGER

Moving a fryer filled with cooking oil may cause spilling or splattering of the hot

liquid.

1. Drain all cooking oil from the fryer.

2. Shut off the gas supply to the unit and disconnect the unit from the gas supply.

3. Remove any attached restraining devices.

DANGER

Fryers must be at room temperature, empty of oil, and if fitted with legs, lifted during

movement to avoid damage and possible bodily injury.

DANGER

Hot shortening can cause severe burns. Avoid contact. Under all circumstances, oil

must be removed from the fryer before attempting to move it to avoid oil spills, and

the falls and severe burns that could occur. This fryer may tip and cause personal

injury if not secured in a stationary position.

4. Relocate the fryer for service accessibility. If fryer is equipped with legs, lift the fryer to relocate

it. Damage to the leg or leg support channel can result if the fryer is not lifted when moving.

5. After servicing is complete, reconnect the unit to the gas supply and reattach the restraining

devices.

6. Refill the frypot with cooking oil.

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 through the tube to remove any obstruction. Remove the

wire and blow through the tube to ensure it is clear.

4. Reinstall tube and bend so that the opening is pointing downward.

1-3

1.4 Calibrating the Operating Thermostat

1. Ensure the frypot is filled to the proper level with oil before proceeding.

2. Light the pilot.

3. Set the temperature control knob to 350°F (177°C).

4. Let the burners cycle on and off automatically three times in order for the oil temperature to

become uniform. If using solid shortening, stir to get all shortening in the bottom of the frypot melted.

5. Insert a good-grade thermometer or pyrometer probe into the oil, with the end near the fryer

temperature-sensing bulb.

NOTE: The temperature-sensing probe is mounted on the frypot tube.

6. When the burner starts for the fourth time, the thermometer/pyrometer reading should be within

the range 335-360°F (168-182°C). If not, calibrate as follows: a. Remove the thermostat knob by pulling straight out on the knob with a firm, steady pull.

The temperature adjusting screw is located in the middle of the thermostat shaft.

b. Insert a small-bladed flat-tipped screwdriver into the adjusting screw. Turn the adjusting

screw in ¼-turn increments to adjust the temperature. Turning the screw clockwise decreases the temperature; turning it counter-clockwise increases the temperature. DO NOT allow the thermostat shaft to turn while turning the adjusting screw.

c. Recheck the thermometer/pyrometer reading the next time the burner comes on. d. Repeat steps 4.b through 4.c until the thermometer/pyrometer reading remains within the

range 335-360°F (168-182°C) through several cycles. If the thermostat cannot be calibrated, call a Factory Authorized Service Center for service.

e. Reinstall the thermostat knob.

1-4

1.5 Check Burner Manifold Pressure

WARNING

This task should be performed by qualified service personnel only.

1. Ensure that the gas valve knob is in the "OFF" position (non-CE), or press red button to turn gas valve off (CE).

2. Remove the pressure tap plug from the gas valve (see illustration below).

3. Insert the fitting for a gas pressure-measuring device into the pressure tap hole.

4. Place the gas valve in the "Pilot" position (non-CE), or press white button and light pilot (CE). After the pilot is lit (turn non-CE gas valve to "ON" position), set thermostat knob to 350°F (177°C). When the burner lights and continues to burn, note gas pressure reading for correct pressure in accordance with the table on page 1-1.

5. To adjust burner gas pressure, remove the cap from the gas valve regulator and adjust to correct pressure.

6. Place the fryer power switch and the gas valve in the "OFF" position. Remove the pressuremeasuring device fitting from the pressure tap hole and reinstall the pressure tap plug.

7. Repeat step 4 to continue fryer operation.

Pressure tap locations on CE gas valves (left) and non-CE gas valves (right).

1-5

1.6 Adjusting the Pilot Flame

1. Remove the cover shown in the illustration below to access the pilot flame adjustment screw in

the gas valve.

2. Using a small, flat-tipped screwdriver, turn the pilot flame adjustment screw counterclockwise to

3. Reinstall the pilot flame-adjustment cover.

4. Five-tube millivolt fryers: Adjust the trailing pilot (adjustment valve located on the burner

Pilot adjustment locations on CE gas valves (left) and non-CE gas valves (right).

increase the length of the flame or clockwise to decrease the length of the flame. Adjust the flame to a length of 1-½ inches (38 mm).

manifold) until a 1-½ inch (38 mm) flame is obtained.

1.7 Replacing Fryer Components

1.7.1 Replacing the Operating Thermostat

1. Drain the fryer and turn the gas off.

2. Remove the thermostat knob by pulling straight out on the knob with a firm, steady pull.

3. Disconnect the wires from the thermostat.

4. Remove the two mounting screws to release the thermostat control from its mounting bracket.

5. Remove the screws and clamp that secure the thermostat bulb to the frypot. Remove spring from

bulb and reinstall on replacement thermostat bulb.

1-6

1.7.1 Replacing the Operating Thermostat (cont.)

6. First, loosen the capillary tube compression fitting until it slides freely on the capillary tube. Second, loosen the frypot pass-through nut until it slides freely on the capillary tube. Remove the capillary tube and bulb from the frypot.

7. Install the replacement thermostat capillary tube and bulb in the frypot. Apply a small amount of Loctite PST567 compound or equivalent to the threads of the frypot pass-through nut and screw the replacement thermostat securely into the frypot, being careful not to twist the capillary tube as the fitting is tightened. DO NOT tighten the capillary tube compression nut at this time.

8. Position the thermostat bulb in tube-mounted clamp and replace mounting hardware. Ensure probe bulb is properly positioned in the clamp (¼" from burner tube) and screws are properly tightened.

9. Tighten the capillary tube compression nut once the capillary tube is properly positioned. NOTE: Once the compression nut is tightened, the capillary tube cannot be repositioned. If a mistake in installation has been made, a new thermostat will have to be installed.

10. Mount the thermostat control to the mounting bracket using the screws removed in Step 4.

11. Connect the wires disconnected in Step 3 to the thermostat.

Compression Fitting

Thermostat Bulb

Capillary Tube

Operating

Thermostat

Frypot Fitting

12. Install the thermostat knob on thermostat control shaft. Check thermostat calibration and calibrate if the range is outside of the recommended ranges in section 1.4.

1-7

1.7.2 Replacing the High-Limit Thermostat

1. Follow instructions for replacing operating thermostat, section 1.7.1, omitting steps 2 and 12.

1.7.3 Replacing the Gas Valve

DANGER

Drain the frypot or remove the handle from the drain valve before proceeding further.

1. Disconnect fryer from the gas supply.

2. Disconnect wiring from the gas valve terminal block, marking each wire to facilitate

reconnection.

3. Disconnect the pilot gas line fitting from the gas valve and remove the vent tube.

4. Disconnect the union that connects burner manifold and gas valve piping.

5. Remove all pipefittings from old gas valve and install on new gas valve. Apply a small amount

of Loctite PST567 compound or equivalent to pipe threads prior to installing on new valve. Do not apply compound to the first two pipe threads. Doing so will clog and damage the gas valve.

6. Reinstall new gas valve following steps 1-4 in reverse.

1.7.4 Replacing the Frypot

1. Drain the frypot and disconnect the fryer from the gas supply.

2. Remove all accessories (e.g., frypot covers, drop-in probes, basket hangers, etc.).

3. Remove the screws from the cabinet back and remove it from the fryer.

4. Remove the screws attaching the flue cap to the frypot and lift the flue cap off the fryer.

5. Remove the door by lifting it upward to disengage the lower hinge pin from the hinge bracket.

Retain any spacers between lower hinge and door for reassembly.

6. Remove the screws from the front cowling and remove the cowling by lifting up and out off the

front lip of the frypot.

7. Remove the screws securing the flue to the frypot and remove it from the fryer.

8. Lift the frypot out of the cabinet, using care not to bump or damage the gas valve/burner

assembly or the thermostat/high-limit. Set the frypot upside down on a clean surface for removal of the remaining components.

1-8

1.7.4 Replacing the Frypot (cont.)

9. Recover the drain valve, high-limit thermostat, operating thermostat, and burner manifold assembly from the failed frypot.

10. Clean the threads on the recovered parts, apply Loctite PST 567 or equivalent thread sealer, and install them on the replacement frypot.

11. Reverse Steps 1-9 to install the replacement frypot in the cabinet.

For SUFF/UFF Filtration-equipped systems, consult the Decathlon Series Gas Fryers Service & Parts Manual (819-5922), Section 1.7.8, for detailed frypot-removal instructions.

1.8 Troubleshooting and Problem Isolation

This section is intended to provide technicians with a general knowledge of the broad problem categories associated with this equipment, and the probable causes of each. With this knowledge, the technician should be able to isolate and correct any problem encountered.

Problems you are likely to encounter can be grouped into these broad categories:

1. Pilot failures

2. Improper burner functioning

3. Improper temperature control

4. Filtration Problems

5. Leaking

The probable causes and corrective actions for each category are discussed in the following sections.

1.8.1 Pilot Failures

When troubleshooting millivolt systems, always check these areas before performing diagnostic checks on either the Robertshaw or Honeywell systems:

A. Inspect all wires and component leads for damage (heat, oil, moisture, etc.). On capillary

tube-type thermostats, check for resistance on the thermostat lead wires. Wire nuts and other connectors cannot be present in a millivolt circuit as they can cause resistance. If resistance is found, solder the connectors to the wires or replace the wires.

B. Clean and verify that all wire connections and gas valve terminal connections are tight. C. Check the length of the pilot flame (it should be about 1½-inches (38mm) long) and verify

that it contacts the top one third of the thermopile. Clean the pilot orifice and adjust the pilot strength if needed.

D. Measure thermopile output with no load (i.e., with the thermopile disconnected from the gas

valve). Measurement must be made with a multimeter having a 0-1000 DC millivolt (MV) range. Light the pilot and have someone hold the gas cock knob in the depressed position. If the thermopile is a single lead (coaxial) type, measure from the lead’s end contact to its screw-in threads. If the thermopile has two leads, measure across the end terminals. The reading should be within the range of 500-800 millivolts. If not, replace the thermopile.

Performing diagnostic checks on Robertshaw and Honeywell valves are described on the next page.

1-9

ROBERTSHAW-UNITROL 7000 SYSTEM CHECK

1. Complete System Check

With thermostat contacts closed and gas cock

dial in the “ON” position, the main burner should ignite. Measure the reading between the 2 & 3 terminals. If the reading is more than 100MV, replace the gas valve.

2. System Resistance Check

With thermostat contacts closed and main

burner “ON”, measure the millivolt reading between the 1 and 3 terminals. The reading should be less than 80MV. If not, recheck the thermostat leads and connections. Replace with new or heavier gauge wires if necessary. If the reading is still greater than 80MV, replace the thermostat.

3. Automatic Pilot Dropout Check

With the thermostat contacts open, hold the gas cock knob depressed with the pilot lit until the maximum millivolt output is observed between the 1 and 2 terminals. Then extinguish the pilot and observe the meter. The sound of the pilot magnet dropping should be audible. This dropout should occur between 120MV and 30MV. If it occurs outside these limits, change the gas valve.

HONEYWELL SYSTEM CHECK

1. Complete System Check

With thermostat contacts closed and gas cock

dial in the “ON” position, main burner should ignite. If not, measure across terminals 2 and 3 as indicated in the diagram. If the reading is more than 180MV, replace the gas valve.

2. System Resistance Check

With thermostat contacts closed and main

burner “ON”, measure the millivolt reading between terminals 1 and 3 as indicated in the diagram. The reading should be 220MV or less. If not, recheck thermostat leads and connections. Replace with new or heavier gauge wires if necessary. If the reading is still greater than 220MV, replace the thermostat.

3. Automatic Pilot Dropout Check

With the thermostat contacts open, hold the gas cock knob depressed with the pilot lit until the maximum millivolt output is observed between terminals 1 and 2. Then extinguish the pilot and observe the meter. The sound of the pilot magnet dropping should be audible. This dropout should occur between 110MV and 36MV. If it occurs outside these limits, change the gas valve.

THTP TH

Test

Meter

Setting

Millivolt Operator

Terminal Panel

(Robertshaw)

Meter Leads

On Terminals

1 MV 2 & 3 <100MV 2 MV 1 & 3 <80MV 3 MV 1 & 2 30-120MV

Millivolt Opera tor

Terminal Panel

(Honeywell)

Test

Meter

Setting

Meter Leads On

Terminals

1 MV 2 & 3 <180MV 2 MV 1 & 3 <220MV 3 MV 1 & 2 36-110MV

Acceptable

Results

Acceptable

Results

1-10

Pilot failures fall into one of two categories – failure to light or failure to remain lit. Pilot Fails to Light

1. Gas is not being supplied to the valve: Check for a closed gas cutoff valve upstream of the gas

valve. Also verify that the gas line quick disconnect fitting at the rear of the fryer (if so equipped) is properly connected.

2. Blocked pilot orifice: If gas is reaching the valve but the pilot will not light, check for an

obstruction in the pilot orifice, especially in new installations. If the orifice is clear, check to be sure that the pilot adjustment screw is not completely closed.

Pilot Does Not Remain Lit When Gas Valve Knob is Released The gas valve used on Dean millivolt fryers has a pair of normally open coils (electromagnetic

switches) that close when low voltage is applied to them. If the coils do not close, the valve will not open to supply gas to the pilot or to the burner manifold. Turning the gas valve knob to the pilot position and pressing it in bypasses the pilot coil, allowing the pilot to be lit. The pilot flam e heats the thermopile, which generates the voltage required to close the coils. If the pilot flame goes out when the knob is released, there are four probable causes:

1. Open or grounded high-limit: The high-limit thermostat functions as a normally closed switch.

If the high-limit is open or grounded, the gas valve coil will not pull in and no gas will be supplied to the pilot or to the burner manifold.

Check and Corrective Action: Detach the high-limit leads from the gas valve and check for continuity. See page 1-10. If the high-limit fails the continuity check, it must be replaced.

2. Loose/corroded wiring connections on high-limit or thermopile: This has the same effect as a

grounded or open high-limit. If the gas valve coils do not receive the appropriate voltage from the thermopile, they will not close and no gas will be supplied to the pilot or to the burner manifold.

Check and Corrective Action: Check wiring connections for corrosion and tightness. Check terminals to verify that they are securely attached to their leads.

3. Low or no voltage out of thermopile: If the pilot flame does not surround the tip of the

thermopile, it will not generate sufficient voltage to the gas valve coils for them to close. No gas will be supplied to the pilot or to the burner manifold.

Checks and Corrective Actions: Observe pilot flame located between the middle burners on the frypot. If the pilot flame is less than 1-½ inches (38 mm) adjust the pilot flame in accordance with Section 1.6. If the flame is being blown away from the thermopile, eliminate the draft that is causing the problem.

If the pilot flame correctly surrounds the tip of the thermopile, see D on Page 1-9.

4. Malfunctioning gas valve: If either of the coils in the gas valve fails, no gas will be supplied to

the pilot or to the burner manifold.

Check and Corrective Action: See page 1-10 for check procedures to see if the gas valve has failed. Instructions to replace the gas valve are found in section 1.7.3.

1-11

1.8.2 Improper Burner Functioning

Fluctuating flame intensity is normally caused by improper or fluctuating incoming gas pressure, but may also be the result of variations in the kitchen atmosphere. Variation in the kitchen atmosphere is usually caused by air conditioning and/or ventilation units starting and stopping. Changes in airflow patterns can also affect flame intensity. If the incoming gas pressure is correct and stable, check for variations in the kitchen atmosphere.

Flames "rolling" out of the fryer are usually an indication of negative pressure in the kitchen. Air is being sucked out of the fryer enclosure and the flames are literally following the air. If negative pressure is not the cause, check for high burner-manifold gas pressure. An obstructed flue, which prevents the fryer from properly exhausting, may also be the cause.

An excessively noisy burner, especially with flames visible above the flue opening, may indicate that the burner gas pressure is too high, the gas valve vent tube is blocked, or the tube diffusers are damaged or worn out. If the gas pressure is correct, the vent tube is unobstructed, and the diffusers are in good condition, the gas valve regulator is probably defective.

Occasionally a burner may appear to be operating correctly, but the fryer has a slow recovery rate (the length of time required for the fryer to increase the oil temperature from 275ºF to 325ºF (135ºC to 163ºC). The primary causes of this are low burner manifold pressure and/or misaligned burners. If both of these causes are ruled out, the probable cause is a gas valve regulator that is out of adjustment. Refer to the Check Burner Manifold Pressure procedure in section 1.5.

1.8.3 Improper Temperature Control (i.e., failure to control at set point)

Temperature control is a function of several interrelated components, each of which must operate correctly. The principle component, however, is the thermostat.

The thermostat must be checked periodically to ensure that it is in calibration. Refer to Calibrating the Operating Thermostat in section 1.4 for the procedure.

If the thermostat is properly calibrated, the probable causes are damage to the thermostat bulb, kinking of the capillary tube, and broken or loose wiring. Inspect the thermostat components for visible damage.

If there are dents in the bulb, if the capillary is kinked, or if there is obvious damage to the leads, the thermostat should be replaced.

If there is no obvious damage to the thermostat, turn off the gas valve and allow the cooking oil to cool to at least 15 degrees below the thermostat setting. Disconnect the thermostat leads from the gas valve and check for continuity. If the thermostat fails the continuity check, it must be replaced.

1-12

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