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SR-GA421/SR-GA281/SR-GA721

2. FUNCTION OF CENTER THERMOSTAT AND THERMALFUSE

A. Center Thermostat

The center thermostat senses when the bottom of the rice cooker pan reach 134°C ± 6°C. 

And it’s action turns off the cooking cycle, and starts the warming cycle.

Refer to these figures showing the center thermostat construction and cooking position. As 

the metal is heated, its ability to be attracted by the magnet decreases.

Finally, the inner spring pressure becomes stronger than the magnetic pull and the metal 

and magnet will pop apart. The rod activates the switch lever which causes the auxiliary lever to 

press the micro-switch button into the warming cycle.

B. Switch-On Preventive System

This is design to prevent the rice cooker from being turned on without the pan placed into 

position.

1) Normally when the pan is inserted properly into the rice cooker, the pan will depress the 

center thermostat. The center thermostat outer spring will be compressed. In this case when 

the switch button is depressed, the following will happen:

a. The auxiliary lever will release the micro-switch button. This puts the micro-switch in the 

cook position.

b. The switch lever will push the rod which will allow the magnet to meet with the metal.

c. When the rice is cooked and the proper temperature has been reached 134°C ± 6°C, the 

metal and magnet will pop apart as described in the center thermostat operation above.

d. The rod will push the switch lever and cause the auxiliary lever to depress the micro-

switch button. This puts the micro-switch in the warming position.

2) When the pan is not in place within the rice cooker, the center thermostat is not depressed.

a. In this condition, the outer spring is not compressed within the center thermostat 

preventing the metal from reaching its normal operating position.

b. When the switch button is depressed, the switch lever and auxiliary lever work as above 

but the magnet cannot come in contact with the metal to hold the switch lever in the cook 

position. This happens because the switch lever hits the thermostat case and cannot push 

the rod, with the magnet attached, all they way up to meet with the metal.

c. When the pressure is taken off the switch button, the switch lever releases immediately to 

the open or warm positions.

Metal 

Magnet 

Inner spring 

Cooking heater 

Rod 

10mm 

Outer spring 

Switch lever 

Cook switch button 

Micro switch 

Thermostat case 

Thermostat surface 

Auxiliary lever 

Metal 

Magnet 

Inner spring 

Cooking heater 

Rod  Inner spring 

Outer  

spring 

Switch lever 

Cook switch button 

Micro switch 

NC 

Center thermostat construction

(Cooking Position)

(Warming or Off Position)

Figure 1

Summary of Contents for SR-GA421

Page 1: ...V 50 Hz 230 V 50 Hz 220 V 50 Hz 240 V 50 Hz 220 V 50 Hz 240 V 50 Hz 230 V 50 Hz 220 V 50 Hz 208 V 60 Hz Power consumption Cooking 1400 W 950 W 2500 W Warming 47 5 W Cooking capacity 5 23 L 5 15 L 3 7 L Center thermostat working temperature 140 C Keep warm temperature More than equal to 80 C After 1 Hr keep warm Thermal fuse specification 113 169 C Dimension mm Width x Depth x Height 429 x 369 x 300...

Page 2: ...nents used in this equipment which are important for safety These parts are marked by in the Schematic Diagrams Circuit Board Diagrams Exploded Views and Replacement Parts List It is essential that these critical parts should be replaced with manufacturer s specified parts to prevent shock fire or other hazards Do not modify the original design without permission of manufacturer IMPORTANT SAFETY NOT...

Page 3: ...y must not overlie the Outer Case of Center Thermostat Water guard Cord Wire Earth Green Silicone Tube Green Thermal Fuse Wire Blue Lever Earth Lead Wire Spiral Green Wiring Lead Wire Brown Lamp Lead Wire A Red Lamp Lead Wire C Brown Twist one time Thermal Fuse Wire Gray Lamp Lead Wire B Gray After assembly Mica Heater case Must no touch the terminal of cast heat Glass tape 20 x 20 mm After ass y ...

Page 4: ...position Heater lead wire C Brown Heater lead wire A Red Grey Brown Red Cathode lead wire Brown Keep warm lamp lead Red 1 0 5 MICA HEATER ASS Y CAST HEATER LAMP RESIST SWITCH LAMP RESIST KEEP WARM NEON LAMP RICE COOKING NEON LAMP SMALL MIDDLE BIG E Green INPUT L N Brown Blue 1 F T 2 F T 1 SCHEMATIC DIAGRAM WIRING DIAGRAM SCHEMATIC DIAGRAM SR GA721 WIRING DIAGRAM SR GA721 ...

Page 5: ...t with the metal c When the rice is cooked and the proper temperature has been reached 134 C 6 C the metal and magnet will pop apart as described in the center thermostat operation above d The rod will push the switch lever and cause the auxiliary lever to depress the micro switch button This puts the micro switch in the warming position 2 When the pan is not in place within the rice cooker the ce...

Page 6: ...TER THERMOSTAT AND THERMALFUSE B Forced application of current Cause Pan collar or deformed Foreign matter adhering Body dented or deformed Pan bottom dented or deformed Heater surface deformed or corroded Remedy Remove foreign matter by of screw driver etc and then polish with 320 water paper while wetting it with water Repair or replace body Replace pan Replace cooking heater Cause Chopstick woo...

Page 7: ...heater Yes Replace sheathed heater Thermal fuse blown Forced application of current Yes Explain correct usage Rice burns Brown color Center thermostat defective Check with evaporation test Yes Replace center thermostat Switch lever has been properly adjusted No Adjust Lever Usage correct Rice is not rinced well enough Using with low rated voltage Too much water input for cooking Yes Explain correc...

Page 8: ...hermostat Switch lever has been properly adjusted No Adjust switch lever Usage correct Too small or large in rice quantity Too small or large in water quantity Switched off once by hand in cooking process Switched off by shocks given in cooking process Rice not untied Explain correct usage Keep warm function Warming fails Warm lamp not shown Micro switch change contact to NO Warm mode after cookin...

Page 9: ... the sheathed heater Check the pan bottom and the sheathed heater for foreign material remained Clean up the foreign materials or replace the parts 2 Evaporation test 1 After satisfactory bubbling is confirmed remove the lid and put a weight on the cooker 2 Cover the entire pan bottom with 2 or 3 pieces of tissue paper or gauze and turn on the switch subsequently 3 The cooker is considered acceptab...

Page 10: ...o switch Check and adjust this relationship as shown below When the boiling switch is turned on When the boiling switch is turned off Checking The auxiliary lever presses the push button The WARM lamp comes on The auxiliary lever does not press the push button The COOK lamp comes on Adjusting To gain the above relationship adjust the auxiliary lever by bending it with long nose pliers ...

Page 11: ...11 SR GA421 SR GA281 SR GA721 5 EXPLODED VIEW PACKING VIEW SR GA421 SR GA281 EXPLODED VIEW SR GA421 SR GA281 ...

Page 12: ...12 SR GA421 SR GA281 SR GA721 5 EXPLODED VIEW PACKING VIEW SR GA421 SR GA281 PACKING VIEW SR GA421 SR GA281 ...

Page 13: ...416 658 K 1 ASR405 507 1 1 8 HANDLE FOR BOBY AQE30T2941K0 1 1 1 1 1 1 9 BODY COMPLETE AQE13T2931WU 1 1 1 AQE13T2931UG 1 AQE13T2941WU 1 AQE13T2941UG 1 10 NAME PLATE AQY50H299 UG 1 AQY50S299 WU 1 AQY50V299 WU 1 AQY50M299 WU 1 AQY50H300 WU 1 AQY50H300 UG 1 11 SWITCH ASS Y AQN00H299WU 1 1 1 1 AQN00H300W9U 1 1 12 SWITCH PANEL AQN10T294 W9 1 1 1 1 1 1 13 DECORATIVE PANEL AQN21T294 W9 1 1 1 1 1 1 14 LAMP...

Page 14: ...No SR GA421 SR GA281 Silver White White White White Silver HK SIN DBD SIN RBD MAL HK HK 1 PACKING CASE AQZ01H299 1 AQZ01S299 1 1 1 AQZ01H300 WU 1 1 2 OPERATING INSTRUCTIONS AQY00H299 1 AQY00S299 1 1 1 AQY00H299 1 1 3 UPPER PAD ASR756 631 K 1 1 1 1 ASR756T607 K 2 2 4 PLASTIC SHEET ASR758 631 K 1 1 1 1 ASR758T503AK 1 1 5 RUST PROOF PAPER ASR758T613B 1 1 1 1 ASR758T607B 1 1 6 LOWER PLATE AQZ16T2931 1...

Page 15: ...15 SR GA421 SR GA281 SR GA721 7 EXPLODED VIEW PACKING VIEW SR GA721 EXPLODED VIEW SR GA721 SR GA721 U S ...

Page 16: ...16 SR GA421 SR GA281 SR GA721 7 EXPLODED VIEW PACKING VIEW SR GA721 PACKING VIEW SR GA721 ...

Page 17: ... COMPLETE AQE13T2951WU 1 1 1 AQE13T2952U2U 1 10 NAME PLATE AQY50M298 WU 1 AQY50S298 WU 1 AQY50V298 WU 1 AQY50A298 N9 1 11 SWITCH ASS Y AQN00M298W9U 1 1 1 AQN00A298W9U 1 12 SWITCH PANEL AQN10T295 W9 1 1 1 ASR22W 590 K 1 13 DECORATIVE PANEL AQN21M298 1 1 1 1 14 LAMP BOARD ASS Y AQN85T29510U 1 1 1 AQN85A29800U 1 15 RICE COOKING LAMP LEAD WIRE AQN86T295 1 1 1 AQN86A298 1 16 MICA HEATER ASS Y AQL70T295...

Page 18: ...EW XYN4 C7FNS 12 12 12 12 G TAPPING SCREW XTN4 20BFJ 2 2 2 2 H TAPPING SCREW XTN4 12AFJ 3 3 3 3 I TAPPING SCREW PK52 4871 1 1 1 1 J TAPPING SCREW XTN4 10AVW 1 1 1 1 PACKING LIST Ref No Part Name Part No SR GA721 White White White Silver MAL SIN DBD SIN RBD USA 1 PACKING CASE AQZ01M298 WU 1 1 1 AQZ01A298 N9 1 2 OPERATING INSTRUCTIONS AQY00M298 1 1 1 AQY00A298 1 3 UPPER PAD ASS Y ASR754A708 1 1 1 1 ...

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