Vulcan Hart C24EA6 Manuel de service

ELECTRIC CONVECTION

SERVICE MANUAL

C24EA SERIES

STEAMERS

C24EA6 SHOWN

This Manual is prepared for the use of trained Vulcan Service Technicians and should not be used by those not properly qualified. If you have attended a Vulcan Service School for this product, you may be qualified to perform all the procedures described in this manual.

- NOTICE -

C24EA6 C24EA10

ML-136058 ML-136059

This manual is not intended to be all encompassing. If you have not attended a Vulcan Service School for this product, you should read, in its entirety, the repair procedure you wish to perform to determine if you have the necessary tools, instruments and skills required to perform the procedure. Procedures for which you do not have the necessary tools, instruments and skills should be performed by a trained Vulcan Service Technician.

Reproduction or other use of this Manual, without the express written consent of Vulcan, is prohibited.

For additional information on Vulcan-Hart Company or to locate an authorized parts and service provider in your area, visit our website at www.vulcanhart.com

A product of VULCAN-HART LOUISVILLE, KY 40201-0696

F35453 (July 2008)

MODEL C24EA

TABLE OF CONTENTS

GENERAL ................................................................................3

COVERS AND PANELS ..................................................................... 5

DOOR.................................................................................... 7

THERMOSTAT AND HIGH LIMITS ............................................................ 12

Heat Exchanger High Limit ............................................................... 12

Steam Generator High Limit .............................................................. 12

Condensate Thermostat ................................................................. 13

TIMERS ................................................................................. 14

HEATING ELEMENTS AND CONTACTORS ....................................................15

HEAT EXCHANGER ELEMENTS AND RELAYS ................................................. 18

WATER LEVEL CONTROL COMPONENTS ..................................................... 21

Water Level Control - Low Level Cut-Off and Differential Operation ............................... 21

Water Level Control .................................................................... 22

Water Level Probes .................................................................... 22

Filtered and Non-Filtered Dual Water Solenoid Valves ......................................... 23

Motorized Drain Valve ..................................................................24

SWITCHES, SOLENOIDS, RELAYS AND BUZZER ............................................... 26

Power and Delime Switches .............................................................. 26

Door Switch ..........................................................................26

Pressure Switch (1PAS) ................................................................. 27

Pressure Switch (2PAS) ................................................................. 29

Vacuum Relief Solenoid .................................................................29

Compartment Steam Solenoid ............................................................ 30

Time Delay Relay ...................................................................... 30

Buzzer .............................................................................. 31

CONTROL BOARD ........................................................................ 32

Layout and LED Legend ................................................................. 33

Steam Generator Operational Status (LED Indicators) ......................................... 34

Deliming Cycle Status (LED Indicators) ..................................................... 38

HEAT EXCHANGER ....................................................................... 42

Motorized Delime Valve ................................................................. 43

STEAM GENERATOR ...................................................................... 44

ELECTRICAL OPERATION .................................................................. 46

Component Location ................................................................... 49

Smart Cycle Power Management .......................................................... 52

Sequence of Operation .................................................................. 52

Schematic Diagrams ................................................................... 58

Wiring Diagrams ....................................................................... 62

TROUBLESHOOTING ...................................................................... 66

©VULCAN 2008

F35453 (July 2008) Page 2 of 68

MODEL C24EA - GENERAL

GENERAL

INTRODUCTION

This manual is applicable to the models and ML numbers listed on the cover page. Procedures apply to all models unless specified otherwise.

Steam Cooking

Convection steamers offer an efficient way to produce many foods in either small portions or larger batches. Convection steam cooking will steam cook fresh foods or will steam defrost and cook frozen foods providing the maximum color, flavor and nutritional value with the least expenditure of energy and labor. The atmospheric steaming compartment allows the operator to open and close the door anytime during a cooking cycle. The generator heating elements will shut off when the door is opened then re-start when the door is closed.

MODELS COVERED

Model Designations (based on 2.5 inch pan

depth) C24EA6 - Six pan (3 pans per compartment) C24EA10 - Ten pan (5 pans per compartment)

SPECIFICATIONS

All C24EA steamers, with exception of 480V steamers, are shipped pre-wired for 208/60/3 operation. Steamer heating element wiring change is required if connecting to 208/60/1, 240/60/1 or 240/60/3 electrical service.

ELECTRICAL SPECIFICATIONS

C24EA6 C24EA10

Volts Phase

208 1 16.9 81 25.6 121 240 1 19.0 79 25.6 110 208 3 16.9 48 25.2 72 240 3 19.0 51 25.6 67 480 3 17.2 21 25.6 32

NOTES:

1. Voltage values are @ 60HZ.

2. Heating elements on three phase

3. Total KW and amps include heat

Total

machines are not wired as a balanced load. The amps listed are the maximum on any leg.

exchanger elements.

Amps

Total

Amps

WATER SUPPLY REQUIREMENTS

Supply pressure should be 20-60 psig In line strainer for supply line

(Supplied) Total dissolved solids (TDS)* less than 60 ppm Total alkalinity less than 20 ppm Silica less than 13 ppm Total Chloride less than 4.0 ppm PH factor 6.5 to 8 Undissolved Solids less than 5 microns *17.1 ppm = 1 grain of hardness Water hardness below 4 grains/gal requires water

treatment to reduce potential corrosion. Hardness above 6 grains/gal should be treated by water conditioner, water softener or in-line treatment.

Water Conditioning

It is recommended that a local water treatment specialist be consulted before the installation of any steam generating equipment.

Furnishing the steam generator with properly conditioned water to reduce scale formation is important. Scale formation will reduce steam output, cause premature component failure and shorten equipment life. Most water supplies contain scale producing minerals such as calcium and magnesium. As steam is generated, the minerals remain and dissolve into the remaining water. As the concentration of these minerals increases past a certain point, they precipitate from the water and coat the inside of the steam generator, heating elements, thermostat bulbs and water level probes. Because of the high temperature of these surfaces, the precipitated minerals bake onto them and become very difficult to remove.

This phenomenon causes several problems:

1. Reduces the heat transfer efficiency of heating elements.

2. Causes premature failure of heating elements.

3. Water level probes will give false readings.

4. Temperature sensing bulbs will sense temperature incorrectly.

These problems are common to any manufacturer's steamer regardless of design, but they can all be prevented by furnishing the steam generator with properly conditioned water. Vulcan recommends the water contain less than 60ppm of total dissolved solids (TDS) and have a PH factor between 6.5 to 8.

F35453 (July 2008)Page 3 of 68

MODEL C24EA - GENERAL

Other chemical properties in water supplies can also affect good steam generation and vary from within each state and locality.

The water level probes in the steam generator use ions in the water to detect the water level. Do not use fully demineralized or de-ionized water since it is non-conductive and the water level can not be detected.

NOTE: The use of strainers, or filters will not remove minerals from the water.

Steamers that operate over a long period of time without the benefit of properly conditioned water, and have developed a heavy scale build up, should be cleaned before connecting to a conditioned water supply.

REFERENCE MATERIAL

For replacement parts, refer to Catalog of Replacement Parts F35454.

For operation, cleaning and maintenance instructions, refer to Installation and Operation Manual F35430.

TOOLS

• Standard set of hand tools.

• VOM with A/C current tester (any quality VOM with a sensitivity of at least 20K ohms per volt can be used).

• Anti Static Kit, Part No. TL - 84919.

Special

• Torque Wrench - Capable of measuring 70 in-lbs.

• Aluminum Foil Tape - (McMaster-Carr Part No. 7631A21) or equivalent.

• Single use Constant Tension Band Clamps for the specific hose size being used. Refer to parts catalog for part number.

• Pressure Gauge Assembly

• Low Pressure Gauge - 0 to 5 psi.

recommended (Grainger Part No. 2C641).

• Water Hose Coupling - swivel type

(Grainger Part No. 4KG87).

LUBRICATION

Component Lubrication Type

All NPT Fittings Pipe Thread Sealant, Loctite 565 Door Handle

Sliding Bracket

Lubriplate 630AA

• Reducer Bushing (Grainger Part No.

6MN61).

• Pipe thread sealant (as required).

F35453 (July 2008) Page 4 of 68

MODEL C24EA - COVERS AND PANELS

COVERS AND PANELS

FRONT BASE PANEL

1. Remove screws from the bottom of panel.

RIGHT AND LEFT SIDE BASE

PANELS

NOTE: Removal of left side panel is identical to the

procedure for the right side panel.

1. Remove FRONT BASE PANEL.

2. Remove screws from the bottom of panel.

2. Pull bottom of panel out and slide down to clear tabletop cover.

3. Reverse procedure to install.

3. Pull bottom of panel out and slide down to clear tabletop cover.

4. Reverse procedure to install.

F35453 (July 2008)Page 5 of 68

MODEL C24EA - COVERS AND PANELS

REAR BASE PANEL

1. Remove electrical power connection to machine.

2. Turn off water supply and disconnect plumbing to machine.

3. Remove screws securing water valves to panel.

4. Remove screws from the bottom of panel.

COOKING COMPARTMENT

RIGHT AND LEFT SIDE PANELS

NOTE: Removal of left side panel is identical to the

procedure for the right side panel.

1. Remove screws from the bottom of panel.

2. Pull bottom of panel out and slide down to clear top cover.

5. Pull bottom of panel out and slide down to clear tabletop cover.

6. Reverse procedure to install.

3. Reverse procedure to install.

F35453 (July 2008) Page 6 of 68

MODEL C24EA - DOOR

DOOR

REMOVAL

1. Close door.

2. Remove COOKING COMPARTMENT LEFT SIDE PANEL as outlined under COVERS AND PANELS.

3. Remove nuts from upper hinge located inside front panel.

4. Open door slightly, and while holding door, pull upper hinge away from front panel.

5. Pull upper hinge out of upper door hinge bushing.

GASKET

1. Open door.

2. Remove the shoulder screws and pan pusher bracket from gasket plate.

3. Remove gasket plate.

4. Remove gasket from inner door panel.

5. Remove RTV from bottom part of inner door panel. Apply RTV 109 to bottom of door where shown when assembling gasket to door.

6. Lift door assembly up and off lower door hinge.

7. Reassemble parts removed in reverse order.

8. Check door for fit and proper sealing of gasket.

6. Place a small amount of RTV109 into the inner door panel gasket screw holes before assembly.

7. Position the new gasket on gasket plate and reverse procedure to install.

F35453 (July 2008)Page 7 of 68

MODEL C24EA - DOOR

DOOR HANDLE

Removal

1. Open door.

2. Remove screws from top and bottom of door assembly.

4. Install lock nuts and tighten until no gap exists between handle, step spacer and lock nut. Do not over-tighten lock nuts.

5. Close inner door panel so that latch mechanism engages striker on front panel.

6. Install outer door housing onto inner door panel.

7. Align the top and bottom screw holes of outer door housing with inner door panel.

3. Pull outer door housing away from inner door panel starting at the hinge side of door to separate the door halves.

NOTE: The smaller radius of the step spacers fit into the slots of the outer door housing and is used to provide clearance for handle operation.

4. Remove lock nuts and stepped spacers from threaded studs of door handle.

Installation

1. Apply Lubriplate 630AA around slots of outer door housing where step spacers contact housing.

8. Install screws to secure door halves together. Apply Loctite 242 to threads of screws before assembly.

9. Check opening and closing operation of door.

2. Install door handle into outer door housing such that hinge side of door housing is to the left and arrow on handle is pointed upward.

3. Install step spacer with smaller radius toward handle and door housing. Smaller radius is a slip fit with outer door housing slot.

F35453 (July 2008) Page 8 of 68

MODEL C24EA - DOOR

LATCH ASSEMBLY

Removal and Disassembly

1. Separate outer door housing assembly from inner door panel as outlined under DOOR HANDLE.

2. Remove screws securing latch assembly to inner door panel and remove latch mechanism.

3. Remove E-clip from latch assembly pins and pull pins from latch mechanism.

Assembly

1. Apply Lubriplate 630AA to sides of sliding bracket.

2. Insert spring pin into bottom of sliding bracket. A. Place spring over spring pin.

3. Assemble sliding bracket into stationary bracket.

4. While holding head of spring pin against bottom of sliding bracket, insert spring pin into keeper hole in bottom of stationary bracket.

4. Remove retaining pin from spring pin.

5. Separate sliding bracket from stationary bracket.

A. Secure spring pin in place with retaining

pin.

NOTE: Install pins such that heads of pins will be facing inward toward hinge side of inner door panel when latch assembly is installed.

5. Install pins to assemble stationary and sliding brackets together.

A. Secure pins into position with E-clip.

F35453 (July 2008)Page 9 of 68

MODEL C24EA - DOOR

Installation

1. Install latch assembly onto inner door panel with spring pin toward bottom of door panel.

A. Apply Loctite 271 to threads of screws

before assembly and secure latch assembly to inner door panel.

2. Install outer door housing assembly as outlined under DOOR HANDLE.

3. Check opening and closing operation of door.

4. Check steamer for proper operation and leaks around door seal.

HINGE BEARINGS

1. Close door.

8. Remove outer door housing.

Do not drive bearing into place. The inner door panel could be damaged. Press bearing into position.

NOTE: When replacing door hinge bearings, replace both hinge bearings.

9. Position replacement hinge bearing over hinge

opening in door assembly.

A. Press hinge bearing fully into door

assembly using a C-clamp or equivalent.

10. Reassemble parts removed in reverse order.

11. Check door for fit and proper door gasket

sealing.

DOOR LATCH ADJUSTMENT

2. Remove COOKING COMPARTMENT LEFT SIDE PANEL as outlined under COVERS AND PANELS.

3. Remove nuts from upper hinge located inside front panel.

4. Open door slightly, and while holding door, pull upper hinge away from front panel.

5. Pull upper hinge out of upper door hinge bearing.

6. Lift door assembly up and off lower door hinge.

Opening a Jammed Door

Should the steamer door jam and cannot be opened, do not force or pry the door as damage will occur.

1. Lift up on bottom of door at the handle end to

disengage latch. A. If door does not open, remove COOKING

COMPARTMENT RIGHT SIDE PANEL as outlined under COVERS AND PANELS.

7. Pry hinge bearing out from door assembly.

F35453 (July 2008) Page 10 of 68

MODEL C24EA - DOOR

B. Locate the striker that catches on door

latch near steam chamber on front panel.

C. Remove the nut from striker and this

should release it from the panel.

Adjustment

1. Reinstall striker with slot pointing upward and

hand tighten nut only.

2. Close door to center striker in front panel

mounting hole.

3. Open door and check striker slot for horizontal

alignment. The slot on striker must be kept horizontal in order for door latch to catch properly and latch.

4. Once proper slot alignment has been set, hold

striker close to its base then tighten the striker nut. Be careful not to damage striker slot when tightening or door may not latch properly.

NOTE: Do not over-tighten nut. If over-tightened, striker may turn and change alignment.

NOTE: If door does not open easily, add shims between striker and cabinet front. When adding shims make certain that door gasket seals properly and steamer does not leak. Remove shims as necessary until leaking stops.

D. Open door.

2. Remove striker.

3. Remove any burrs on striker that may cause latch to stick.

4. Apply Loctite 271 to threads of striker.

5. Reinstall striker with slotted side up. Snug striker nut. Perform Adjustment, so door will not jam.

F35453 (July 2008)Page 11 of 68

MODEL C24EA - THERMOSTATS AND HIGH LIMITS

THERMOSTAT AND HIGH LIMITS

HEAT EXCHANGER HIGH LIMIT

1. Turn off machine to drain steam generator. Allow steamer to complete drain cycle.

2. Remove RIGHT SIDE BASE PANEL as outlined under COVERS AND PANELS.

3. Disconnect electrical lead wires from heat exchanger high limit.

4. Loosen hose clamps securing heat exchanger high limit to the heat exchanger surface.

STEAM GENERATOR HIGH LIMIT

Removal

1. Turn off machine to drain steam generator. Allow steamer to complete drain cycle.

A. Turn off water supply.

2. Remove FRONT BASE PANEL as outlined under COVERS AND PANELS.

3. Remove heating element (1HTR) from steam generator as outlined under HEATING ELEMENTS AND CONTACTORS.

4. Fully loosen capillary tube compression nut and slide it away from heating element.

5. Remove capillary tube mounting nut from heating element mounting plate.

5. Remove heat exchanger high limit.

6. Disconnect electrical wiring to high limit.

7. Remove high limit from the rear of low voltage

6. Reassemble parts removed in reverse order.

7. Check steamer for proper operation.

F35453 (July 2008) Page 12 of 68

control box.

MODEL C24EA - THERMOSTATS AND HIGH LIMITS

RIGHT SIDE SHOWN

4. Secure high limit to low voltage control box then coil excess capillary tube length near the high limit.

5. Check steamer for proper operation and leaks around heating element gasket and high limit capillary tube nuts.

CONDENSATE THERMOSTAT

1. Turn off machine to drain steam generator. Allow steamer to complete drain cycle.

A. Turn off water supply.

8. Remove capillary tube from heating element.

Installation

1. Route capillary bulb through the opening in heating element mounting plate. Ensure there are no sharp bends in capillary tubing while installing.

A. Insert capillary bulb into the holding tube

on heating element.

2. Apply pipe thread sealant to threads then install large capillary tube mounting nut.

A. Ensure capillary bulb is centered in the

holding tube. Tighten the capillary tube compression nut.

2. Remove RIGHT SIDE BASE PANEL as outlined under COVERS AND PANELS.

3. Disconnect electrical wiring to condensate thermostat.

4. Remove condensate thermostat from the rear of drain box.

REAR OF DRAIN BOX SHOWN

3. Install heating element with a new gasket. Torque mounting nuts to 70 in-lbs and tighten using an alternating pattern.

5. Reassemble parts removed in reverse order. Apply pipe thread sealant to threads of thermostat before assembly.

6. Check steamer for proper operation and leaks around condensate thermostat.

F35453 (July 2008)Page 13 of 68

MODEL C24EA - TIMERS

TIMERS

REMOVAL AND REPLACEMENT

NOTE: When the timer reaches zero, an external

buzzer will sound and steam will stop entering the cooking compartment. The constant steam setting allows for continuous steam operation.

1. Remove COOKING COMPARTMENT RIGHT SIDE PANEL as outlined under COVERS AND PANELS.

2. Note electrical connections then disconnect wiring from timer being serviced.

UPPER COMPARTMENT SHOWN

3. Pull knob from timer shaft. A. Remove rotary shaft seal from timer shaft

then remove timer from front panel.

B. Inspect rotary shaft seal. Replace if

damaged, worn or signs of moisture migration into control area around timer shaft is evident.

4. Reverse procedure to install.

5. Check steamer for proper operation.

F35453 (July 2008) Page 14 of 68

MODEL C24EA - HEATING ELEMENTS AND CONTACTORS

HEATING ELEMENTS AND CONTACTORS

REMOVAL AND REPLACEMENT

Heating Elements

1. Turn off machine to drain steam generator. Allow steamer to complete drain cycle.

A. Turn off water supply.

2. Remove FRONT BASE PANEL as outlined under COVERS AND PANELS.

3. Remove top screw securing cover to high voltage box.

4. Note electrical connections for the heating element being replaced then disconnect heating element lead wires from contactors.

HEATING ELEMENT (1HTR) WITH STEAM

GENERATOR HIGH LIMIT SHOWN

5. Remove mounting nuts and lock washers securing heating element to steam generator.

A. If replacing heating element (1HTR),

remove STEAM GENERATOR HIGH LIMIT.

B. Pull heating element out of steam

generator.

6. Reassemble parts removed in reverse order. Torque mounting nuts to 70 in-lbs and tighten using an alternating pattern.

NOTE: When installing heating element 2HTR or 3HTR, install pipe plug in the center of heating element mounting plate. Apply pipe thread sealant to threads before assembly. Use a new gasket whenever installing a heating element.

NOTE: Refer to STEAM GENERATOR HIGH LIMIT for proper placement of capillary bulb.

7. Check steamer for proper operation and leaks around heating element.

F35453 (July 2008)Page 15 of 68

MODEL C24EA - HEATING ELEMENTS AND CONTACTORS

Contactors

1. Turn off machine to drain steam generator. Allow steamer to complete drain cycle.

2. Remove FRONT BASE PANEL as outlined under COVERS AND PANELS.

3. Remove top screw securing cover to high voltage box.

4. Note electrical connections for the contactor being replaced then disconnect lead wires from contactor terminals and coil.

5. Remove screws securing contactor to high voltage control box then remove contactor.

HEATING ELEMENTS

DIAGNOSTIC CHECK

1. Check voltage across heating element lead wires at the limiting and regulating contactor terminals and verify against data plate.

A. If voltage is correct, check current draw

(step 2).

B. If voltage is not correct, check the

following:

1) Voltage supply to steamer.

2) Fuses or breaker blown.

6. Reassemble parts removed in reverse order.

7. Check steamer for proper operation.

3) Power to contactor coils.

4) Contactors not pulling in (mechanical problem).

2. Check current draw (amps) through heating element lead wires using an amp clamp meter.

NOTE: Checking current draw is the preferred method over a resistance check when an amp clamp meter is available.

A. If current is correct, then heating element is

ok. See table for proper values.

B. If current is not correct, turn power switch

off and disconnect power to machine.

1) Install a replacement heating element.

F35453 (July 2008) Page 16 of 68

MODEL C24EA - HEATING ELEMENTS AND CONTACTORS

3. If unable to check current draw, a resistance check may indicate a malfunctioning element. A. Turn power switch off and disconnect power to machine. B. Disconnect heating element lead wires and check the individual element resistance using a VOM. C. If resistance readings are not correct, replace heating element.

4. Check steamer for proper operation.

VOLTAGE

208

240

480

208

240

480

Dual voltage elements.

KW PER

ELEMENT

8.0 12.8 16.2

10.5 14.8 16.2

8.0 9.6 28.8

8.0 12.8 16.2

10.5 14.8 16.2

8.0 9.6 28.8

CURRENT PER

ELEMENT

RESISTANCE PER ELEMENT (OHMS)

480V elements are connected in Wye configuration for 277V across each element.

NOTE: Values in table are nominal. Tolerance is ±10 %.

F35453 (July 2008)Page 17 of 68

MODEL C24EA - HEAT EXCHANGER ELEMENTS AND RELAYS

HEAT EXCHANGER ELEMENTS AND RELAYS

REMOVAL AND REPLACEMENT

Heat Exchanger Elements

1. Turn off machine to drain steam generator. Allow steamer to complete drain cycle.

A. Turn off water supply.

2. Remove FRONT BASE PANEL and RIGHT SIDE BASE PANEL as outlined under COVERS AND PANELS.

3. Note electrical connections for the heat exchanger element being replaced then disconnect lead wires from heat exchanger relay and contactor.

4. Remove motorized control assembly from delime valve. Rotate the assembly CCW approximately 1/8 turn to disengage from delime valve.

NOTE: When installing, align the flat on delime valve stem and the locking pins on delime valve to the motorized control assembly.

NOTE: The two electrical plugs on the motorized control assembly are identical. Note location of electrical wiring if disconnecting from motorized control assembly. If the electrical plugs not connected correctly, the motorized delime valve will not function.

5. Remove heat exchanger element from heat exchanger.

NOTE: To access heat exchanger element (1), remove heat exchanger element (2) and the 3/8" vent tube on vacuum relief valve (outlet side).

F35453 (July 2008) Page 18 of 68

MODEL C24EA - HEAT EXCHANGER ELEMENTS AND RELAYS

HEAT EXCHANGER ELEMENTS

DIAGNOSTIC CHECK

1. Check voltage across heat exchanger element lead wires at the limiting and regulating contactor terminals and verify against data plate.

6. Reassemble parts removed in reverse order. Apply pipe thread sealant to threads of heat exchanger element before assembly.

7. Check steamer for proper operation and leaks around heat exchanger element.

Heat Exchanger Relays (K10, K12)

1. Turn off machine to drain steam generator. Allow steamer to complete drain cycle.

2. Remove FRONT BASE PANEL as outlined under COVERS AND PANELS.

3. Remove top screw securing cover to high voltage control box.

4. Note electrical connections for the heat exchanger relay being replaced then disconnect lead wires from relay terminals and coil.

5. Remove screws securing heat exchanger relay to high voltage control box then remove relay.

A. If voltage is correct, check current draw

(step 2).

B. If voltage is not correct, check the

following:

1) Voltage supply to steamer.

2) Fuses or breaker open.

3) Heat exchanger relay (K10) (heat exchanger element 1) or heat exchanger relay (K12) (heat exchanger element 2).

4) Power to contactor coils.

5) Contactors not pulling in (mechanical problem)

2. Check current draw (amps) through heat exchanger element lead wires using an amp clamp meter.

NOTE: Checking current draw is the preferred method over a resistance check when an amp clamp meter is available.

A. If current is correct, then heat exchanger

element is ok. See table for proper values.

6. Reassemble parts removed in reverse order.

7. Check steamer for proper operation.

B. If current is not correct, turn power switch

off and disconnect power to machine.

1) Install replacement heat exchanger element.

F35453 (July 2008)Page 19 of 68

MODEL C24EA - HEAT EXCHANGER ELEMENTS AND RELAYS

3. If unable to check current draw, a resistance check may indicate a malfunctioning element. A. Turn power switch off and disconnect power to machine. B. Disconnect heat exchanger element lead wires and check resistance using a VOM. C. If resistance is not correct, replace heat exchanger element.

4. Check steamer for proper operation.

MODEL VOLTAGE

208

C24EA6

240 480 208

C24EA10

240 480

Dual voltage elements.

WATTS PER

ELEMENT

450 2.20 96.1 600 2.50 96.0 600 2.20 128.0 600 2.90 72.1 800 3.30 72.0 800 2.90 95.9

CURRENT PER

ELEMENT

RESISTANCE PER ELEMENT (OHMS)

480V Elements are connected in Wye configuration for 277V across each element.

NOTE: Values in table are nominal. Tolerance is ±10 %.

F35453 (July 2008) Page 20 of 68

MODEL C24EA - WATER LEVEL CONTROL COMPONENTS

WATER LEVEL CONTROL COMPONENTS

WATER LEVEL CONTROL - LOW LEVEL CUT-OFF AND

DIFFERENTIAL OPERATION

The steamer is equipped with three water level sensing probes (high, low and low level cut-off) and a water level control. The water level control performs two functions:

1. Provide low level cut-off protection to shut off the heat source in case the water level drops below the low level cut-off (LLCO) probe.

2. Perform as a differential level control to maintain the water level between the low and high water level probes.

The water level control (WLC) has input voltage (120VAC) across terminals 11 and 12 which powers the primary side of the transformer. On one side of the transformer secondary, power is provided to the control by a series path through chassis ground (terminal 10). The other side of the transformer secondary (12VAC) is attached to the probe that directs power to the other side of WLC relay coils (LLCO and HL) and to the inverse latching relay (ILR) electronic circuit on the WLC. As water enters the steam generator, it becomes part of the WLC circuit. When the water level in the steam generator reaches a probe, that circuit is completed.

The inverse latching relay of the WLC is de-energized, leaving the ILR-1 (N.O.) and ILR-2 (N.C.) contacts in their shelf state.

When the main power switch is turned on, power is supplied to the WLC which energizes the high level (HL) relay, closes HL-1 normally open contacts, and illuminates the HL relay LED. With the HL-1 contacts closed, the slow fill solenoid is energized and water begins filling the steam generator.

When the water level reaches the low level cut-off (LLCO) probe, the LLCO relay is energized and illuminates the LLCO LED. With the LLCO-1 contacts closed, the heat source can be energized provided the auxiliary control(s) in the heating circuit are satisfied. The LLCO relay will remain energized and its LED will stay lit until the water level in the steam generator drops below the LLCO probe.

When the water level reaches the low level (LL) probe, power to terminal 2 on the WLC is present but no switching occurs.

After the water level reaches the high level (HL) probe, the inverse latching relay of the WLC is energized and locked through the low level probe (LL) and ILR-1 contacts. With ILR-2 contacts open, HL relay is de-energized and the HL LED goes out. With the HL-1 contacts open, the slow fill solenoid is de-energized, stopping the flow of water into the steam generator.

When the water level drops below the low level (LL) probe, power is removed from the inverse latching relay, the HL relay energizes through ILR-2 and HL contacts change state. The slow fill solenoid is energized through HL-1 to refill the steam generator and the HL LED is lit. The HL relay and LED will toggle on and off during a cooking cycle as needed.

F35453 (July 2008)Page 21 of 68

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