background image

PRINCIPLES OF OPERATION

10

is directed into the boiler (or direct-connected steam 

control) drain system. Steam inlet lines for compart-

ments  are  equipped  with  normally  closed  solenoid 

valves operated by the electrical control circuits. The 

inlet valves are opened whenever the compartment 

control circuit is activated by use of the 60 minute tim-

ers.

STEAM INLET LINE:

A steam supply line is plumbed from the boiler output 

(or direct-connected steam control) to a 1/2 inch barb 

fitting connected to the input sides of both steam inlet 

solenoid valves. When a cooking compartment is not 

in use, the valve for the compartment remains closed 

to prevent steam from entering. During operation, the 

appropriate inlet solenoid valve is opened by activa-

tion of the control circuit. 

Steam is projected onto the surface of pans of food 

loaded  into  the  compartment  by  an  orifice  located 

inside  the  compartment.  Steam  continues  to  flow 

through the compartment in this manner until the con-

trol circuit closes the solenoid valve.

STEAM EXHAUST AND DRAIN LINES:

Perforated strainers at the drain line openings inside 

each compartment allow only steam, condensation, 

and  liquid  cooking  drainage  to  enter.  Prior  to  dis-

charge into the boiler drain system, steam is convert-

ed to water by the cold water condensing systems for 

each compartment.

STEAM EXHAUST CONDENSING SYSTEM:

The steam condensing system consists of the identi-

cal, two-position, normally closed cold water solenoid 

valves, with outlet sides connected into the exhaust 

plumbing  for  each  cooking  compartment.  A  spray 

nozzle directs cold water about the inside of the drain 

lines to increase cold water contact with exhausted 

steam. 

Valve inlet sides are connected remote from the sup-

ply line of the steam boiler (or direct-connected steam 

plumbing).  The  valves  respond  to  a  thermostatic 

switch  located  inside  the  compartment.    When  the 

timer starts the cold water solenoids will energize.

ELECTRICAL CIRCUITS:

The electrical circuits of the cooker control the power 

to activate timer motors and energize solenoid-oper-

ated valves and circuits, which in turn control applica-

tion of steam to the cooking compartment and con-

densation of steam from the exhaust line. The cooker 

operates  on  120V,  2 amp,  60Hz  electrical  service 

connected to all circuits from the circuits of the steam 

boiler (or direct-connected steam controls) contained 

within the cabinet on which the cooker is mounted. 

Power  is  supplied  to  the  control  circuit  at  all  times 

when the shut-off device for the unit (supplied by the 

user) is in the ON position.

CONTROL  CIRCUIT  COMPONENTS:

  A  brief  de-

scription of the electrical circuit elements follows.

60 MINUTE TIMER/CONSTANT STEAM:

The timer contains a 120-volt AC synchronous mo-

tor that drives a timing dial through a gear reduction 

and clutch mechanism. The timer dial is manually set 

for any interval of operation from 0 to 60 minutes or 

constant steam as read on the calibrated dial face. 

The manual rotation of the dial moves the common 

element (1) of the timer switch from the neutral (OFF) 

position to contact (3), which connects with the steam 

inlet solenoid valve operating circuit. 

The  cooker  is  placed  into  automatic  operation  with 

the setting of the timer dial. Its timing cycle, however, 

is  automatically  delayed  by  a  thermostatic  switch, 

which assures operating temperature is achieved be-

fore the timer motor begins to “time out.” When the 

timer motor has operated for the preset duration, the 

common element is transferred to contact (4), return-

ing the inlet solenoid valve to the closed position and 

energizing the buzzer. Contact to the buzzer circuit 

remains closed until the dial is manually turned to the 

OFF  position,  returning  the  common  element (1)  of 

the timer switch to the neutral position.

Summary of Contents for 3500 Power-Plus

Page 1: ...and liquids in the vicinity of this or any other appliance Post in a prominent location instructions to be followed in the event the user smells gas This information shall be obtained by con sulting the local gas supplier An Employee Owned Company 35 Garvey Street Everett MA 02149 Tel 617 387 4100 Fax 617 387 4456 Toll Free 866 698 3188 Outside MA Fax 800 227 2659 E mail custserv mfii com Web site...

Page 2: ...OMPONENTS 10 PICTORIAL DIAGRAM OF STEAM AND WATER 11 CIRCUITS 11 INDICATOR LIGHTS 11 BUZZER 11 DOOR INTERLOCK SWITCH 11 THERMOSTATIC SWITCH 11 TROUBLE SHOOTING GENERAL 12 GENERAL TROUBLE SHOOTING GUIDE 12 INCOMING POWER 13 ELECTRIC INSPECTION 13 60 MINUTE TIMER 13 TIMER CONTACTS 13 ELECTRICAL FAULT ISOLATION GUIDE 13 WIRING AND SCHEMATIC DIAGRAM FOR MODEL 3500 ONLY 14 WIRING AND SCHEMATIC DIAGRAM ...

Page 3: ...i cator light comes on and the steam solenoid valve opens allowing steam to flow into the compartment When steam flowing inside the compartment has raised the interior temperature to 195 F the contacts of a thermostatic switch automatically close complet ing the circuit to the timer motor and starting the cook ing time period At the end of the set interval timer contacts switch to shut off the coo...

Page 4: ...that fails to meet these stan dards should be treated by the installation of a water conditioner 1 2 3 4 5 6 Equipment failure caused by inadequate water qual ity is not covered under warranty CAUTION PVC or CPVC are not acceptable materials for drains INSTALLATION CHECK OUT Check out procedures for the cooker mounted on steam boilers of electric gas and steam coil utility or direct connected stea...

Page 5: ...e Remove the two white hole plugs from the left door latch mounting holes and insert them into the right door latch mounting holes where the door latch assembly was originally mounted Rotate the door latch assembly 180 and install into the left door latch mounting holes NOTE Each stud on the latch assembly should have a plastic washer a spring a plastic washer and a Nyloc type nut To adjust the te...

Page 6: ...5 6 out of the compartment and then fully open the door Unload by sliding pans of food from pan supports taking care to avoid hitting compartment opening SHUT DOWN PROCEDURE No shut down procedure is required for the cooker except to check that both timer dials 1 are in the OFF position and that both compartment doors are open When all cooking has been completed for the day the steam source must b...

Page 7: ...CATORS Refer to Fig 1 ITEM DESCRIPTION FUNCTION 1 Timer Constant Steam Controls cooking up to 60 minutes for uses constant operation 2 Indicator Light Red Indicated when lit that the cooker is in operation 3 Buzzer Not Shown Signals end of cooking period ...

Page 8: ...pared closer to serving time insuring maximum freshness Steam cooked foods have a higher percent yield more portions per dollar spent Food may be served from the same pan in which it is steam cooked thus reducing food breakage since there is no extra handling or transferring of food from cooking pans to serving pans It also reduces pot washing tasks Some important advantages of steam cooking are l...

Page 9: ... 7 kg 2 1 2 65mm 1 3 10 15 25 3 oz 85g Beans Green French Cut 6 lbs 2 7 kg 2 1 2 65mm 1 3 5 7 25 3 oz 85 g Beans Lima 7 1 2 lbs 3 4 kg 2 1 2 65mm 1 3 12 15 30 3 oz 85 g Broccoli 6 lbs 2 7 kg 2 1 2 65mm 1 3 4 6 25 3 oz 85 g Brussel Sprouts 7 1 2 lbs 2 7 kg 2 1 2 65mm 1 3 10 15 30 3 oz 85 g Carrots 6 lbs 2 7 kg 2 1 2 65mm 1 3 10 15 25 3 oz 85 g Cauliflower 6 lbs 2 7 kg 2 1 2 65mm 1 3 7 12 25 3 oz 85...

Page 10: ...g 2 1 2 65mm 1 3 20 25 25 30 4 oz 115 g Peas Shelled 5 lbs 2 25 kg 2 1 2 65mm 1 3 5 6 25 30 3 oz 85 g Potatoes French Fry Cut 10 lbs 4 5 kg 2 1 2 65mm 1 3 18 21 50 3 oz 85 g Potatoes Regular Cut 3 10 lbs 4 5 kg 2 1 2 65mm 1 3 35 40 50 3 oz 85 g Spinach Cleaned Cut 3 lbs 1 4 kg 2 1 2 65mm 1 3 3 5 10 12 3 3 4 oz 105 g Squash Summer Sliced 1 thick 7 lbs 3 2 kg 2 1 2 65mm 1 3 7 10 30 35 3 oz 85 g Squa...

Page 11: ...3500 Pressureless Steam Cooker consists of two identical cooking compartments one above the other in a single cabinet assembly Each compartment is fitted with independent electrically controlled steam circuits and spring loaded self sealing doors with slam action latches Compartments can be used sep arately or simultaneously for either constant steam or 60 minute timing The principles of operation...

Page 12: ...steam plumbing The valves respond to a thermostatic switch located inside the compartment When the timer starts the cold water solenoids will energize ELECTRICAL CIRCUITS The electrical circuits of the cooker control the power to activate timer motors and energize solenoid oper ated valves and circuits which in turn control applica tion of steam to the cooking compartment and con densation of stea...

Page 13: ...ally open contacts The switch is operated by the proximity of a magnet within the door When the door is open the switch contacts remain in the open position When the door is closed and secure ly latched in place the magnet is near the switch to close the contacts Connected between the operating contact 3 of the timers and the steam inlet solenoid valve the door switch acts as a protective device t...

Page 14: ...lock switch faulty Replace switch Refer to door interlock switch section on page 15 D Indicator light burned out Replace light E Faulty timer contacts Replace timer Refer to 60 minute timer section on page 13 F Faulty wiring Inspect condition of wire and tightness of all connections Correct as needed 2 STEAM FAILS TO ENTER COMPARTMENT WITH INDICATOR LIGHT ON A Faulty steam solenoid valve Replace v...

Page 15: ...s of all connection points are tightly secured Use a screwdriver to tighten connection points If nec essary visually inspect all quick disconnect terminals for evidence of corrosion Terminals in this condition should be separated cleaned with emery cloth until shiny and tightly reconnected 60 MINUTE TIMER TIMER CONTACTS Defective timer contacts will result in failure of either cooker compartment t...

Page 16: ...TROUBLE SHOOTING MODEL 3500 ONLY 14 Fig 3 Wiring and Schematic Diagram for Model 3500 ONLY ...

Page 17: ...15 TROUBLE SHOOTING MODEL 3500 POWER PLUS ONLY Fig 4 Wiring and Schematic Diagram for Model 3500 POWER PLUS ONLY 10641 2 0 4106 1661 219 4 2 75 56Ä 1 2 46 06 612 ...

Page 18: ...ch by closing the cooking compart ment door If a zero reading cannot be obtained the switch is defective and must be replaced 5 Remove the ohmmeter and replace the leads on switch terminals see Fig 2 page 11 STEAM SOLENOID VALVES When either inlet solenoid valve fails to operate the fault may be a defective coil A defective coil is found using an AC volt meter to check the voltage at the coil wire...

Page 19: ...n page 11 If all of the electrical components are operating cor rectly and the incoming power has been checked but the cooker fails to operate the fault lies in the wiring Fig 2 on page 11 is a diagram that shows all ter minals and interconnections within the electrical cir cuits All numbered terminals are identified and all leads number coded as shown Connections can be easily removed Figure 3 on...

Page 20: ...or Remove the control panel by removing the eight mounting screws and disconnecting the wire plug and restraining wire Tighten both nuts down until the springs are fully compressed Back each nut off 1 2 turn Remount the control panel reconnecting wire plug and restraining wire 1 2 3 4 5 ILLUSTRATED PARTS LIST GENERAL This section contains a complete listing of all re placeable parts of the 3500 Fo...

Page 21: ...ILLUSTRATED PARTS LIST 19 Fig 5 Cabinet Assembly ...

Page 22: ...S 2 13 08 1207 BARB 1 IPS 2 14 91 7638 STIFFENER BACK 1 15 91 7639 BRACKET LINER TIE 1 16 98 3503 PANEL BACK 1 17 91 7619 PANEL TOP 1 18 98 3505 PANEL SIDE 2 19 91 7690 BRACKET REED SWITCH 2 20 08 6308 REED SWITCH 2 21 10 8105 THERMOSTAT CONDENSER 3500 ONLY 2 22 10 3739 REDUCER 1 2 IPS X 3 8 IPS 2 23 10 4586 NUT SEALER 1 2 IPS 4 24 10 9175 RELAY SOCKET 4 25 98 3511 CONTROL PANEL ASSY 1 26 91 7697 ...

Page 23: ...M PART NO DESCRIPTION QTY 1 91 5729 OUTER DOOR 1 2 91 5766 INNER DOOR 1 3 91 5731 GASKET RETAINING PLATE 1 4 91 5286 DOOR GASKET 1 5 91 5745 DOOR HANDLE 1 6 09 1608 STRIKER 1 7 08 5027 MAGNET 1 8 91 5901 MAGNET BRACKET 1 9 08 4600 COMPRESSION SPRING 2 ...

Page 24: ...mbly ITEM PART NO DESCRIPTION QTY 1 98 3504 CONTROL PANEL 1 2 98 3507 ARTWORK CONTROL PANEL 1 3 08 6464 60 MIN TIMER 2 4 08 6541 TERMINAL STRIP 2 5 91 6471 BRACKET TERMINAL STRIP 2 6 10 7395 BUZZER 2 7 08 3826 KNOB TIMER 2 8 10 5052 LIGHT RED ON OFF 2 ...

Page 25: ... LIST Fig 8 Condenser Assembly ITEM PART NO DESCRIPTION QTY 1 91 7640 CONDENSER BRACKET 1 2 08 4821 CONDENSER SOLENOID 3500 ONLY 2 3 08 4864 HOSE BARB 90O 1 8 IPS 3500 ONLY 3 4 08 5009 TEE 1 8 IPS x 1 4 ID HOSE 3500 ONLY 1 ...

Page 26: ...3539 Bushing 1 2 x 1 4 Hex 1 6 08 5438 Tee Brass 1 x 1 2 x 1 1 7 08 1207 Hose Fitting 1 NPT 1 8 15 7208 Braided Stainless Steel Hose 2 1 2 1 9 08 4864 Hose Barb 90o 1 8 IPS 2 10 08 1206 Hose Clamp 2 11 08 7923 Tee 1 8 NPT 1 12 08 4890 Hose Coupler 1 8 IPS x 1 4 ID 2 13 91 6491 Grommet 1 14 08 4866 Spray Nozzle 3500 ONLY 1 15 08 4821 Condenser Solenoid 3500 ONLY 2 16 91 7640 Condenser Bracket 1 ...

Page 27: ...Fig 10 3500 Power Plus ITEM PART NO DESCRIPTION QTY 1 10 9175 RELAY SOCKET ONE PER COMPARTMENT 2 2 10 9174 CUBE RELAY ONE PER COMPARTMENT 2 3 08 6502 PRESSURE SWITCH 2 4 98 4206 POWER SUPPLY 5 VDC 1 5 97 6455 TIME DELAY RELAY 2 ...

Reviews: