Rice cooker will not switch to cook or the rice stays raw: thermostat and sensor

• Switch off the MCB and unplug the appliance before checking anything.
• Make sure your hands and the floor are dry.
• Let the appliance cool down before touching anything inside it.
• Keep your hands and face away from hot steam.

For a rice cooker, unplugging it from the socket is enough. The heating plate at the bottom stays hot for a while after you unplug it.

A rice cooker decides that the rice is done based on the temperature at the bottom of the pot. As long as there is water left, the temperature at the bottom of the pot stays capped; once the water is absorbed, the temperature rises and the cooker switches from cook to keep warm. So two things matter a great deal: the pot must sit firmly on the heating element, and the temperature sensor and its switch must be clean. The Philips HD4812 rice cooker manual says the heating element, the temperature sensor and the outside of the inner pot must be clean and dry before you plug it in. It also says the inner pot must make proper contact with the heating element.

If dried rice, crust or water is trapped between the pot and the heater, the heat does not pass through properly. The sensor can then read a high temperature too early, so the cooker switches to warm before the rice is done, or the switch will not stay in the cook position. The same manual says nothing should be left on the heating element or the magnetic switch.

Another cause is how it was switched on. The Philips troubleshooting table mentions that the control button may not have been pressed down. On models with a lever, press the lever until it locks.

1. Cord and light. Philips treats a light that does not come on as a connection problem. Check that the power cord is plugged in properly at the cooker and that the plug is all the way in the socket. Many rice cookers use a detachable cord whose end easily works loose.
2. Pot bottom and heating plate. With the plug pulled and the cooker cool, lift out the inner pot. Look for dried rice, crust or leftover water on the heating plate and the sensor in its center. Clean them with a damp cloth, then dry them. Wipe the underside of the pot too.
3. Pot shape. Philips names a misshapen inner pot as one cause of undercooked rice. A dented pot does not sit flat on the heater; put it on a flat table and see whether it rocks.
4. Pot seating. Put the pot back and turn it slightly until it sits flat on the heater, then close the lid firmly.
5. Water level. Add water up to the line in the pot that matches the number of measuring cups of rice. As an alternative, Philips gives a rice-to-water ratio of 1:1-1,2, without going past the mark in the pot. Wash the rice in a separate bowl so you do not damage the pot's nonstick coating.
6. Press the button or lever all the way down. Then check that the cook light comes on and stays on.

Philips Indonesia's support page on undercooked rice gives four possibilities. First, there is not enough water; measure the rice with the measuring cup that came with the cooker. Second, grains and beans with a hard skin, such as red beans, black beans or Job's tears, need to soak first. Third, make sure there is nothing on the outside of the heating element or inside the cooker before switching it on. Fourth, the heating element may be damaged or the inner pot misshapen, and for that Philips says to take the cooker to a service center.

The type of rice matters too. Different rice needs different amounts of water, and the Philips manual calls the marks in the pot only a guide that you can adjust to the rice type and your taste. Brown rice and grain mixes usually need a longer program or cooking time.

The mains voltage plays a part too. The Philips manual notes that if the voltage is unstable where you live, the rice cooker may boil over. It adds that the actual cooking time can vary with the amount of rice, the water, the voltage and the temperature. The HD4812 is rated at 400W on 220V, the Indonesian household supply; a low-power appliance like this cooks more slowly when the household voltage drops at peak hours. If the rice is often hard only in the late afternoon, note the pattern.

A digital rice cooker has several programs with different times and heating patterns. The program table in the Philips HD4812 manual, for example, lists a default of 25 minutes for quick cook. White rice takes between 50 and 70 minutes depending on the chosen texture, and brown rice takes 120 minutes. If the rice is hard or undercooked, first check that the selected menu suits the rice type; quick cook with the usual amount of water can give a different result from the white rice program.

Programs with a delay timer can also be confusing: the cooker seems to do nothing because it is waiting for its scheduled start. Look at the timer indicator on the panel. If the menu is right, the time is up and the rice is still raw, go back to the pot, sensor and water checks above.

The Philips manual says to clean the surfaces that touch food with a soft damp cloth and to remove all food residue. If the rice smells bad, the manual suggests washing the inner pot with dish soap and warm water and, after cooking, cleaning the steam vent cap, the inner lid and the pot thoroughly.

• Do not put the cooker's body in water; the Philips manual lists this as a danger.
• Do not push metal objects or anything else into the steam vent.
• Do not plug in or press buttons with wet hands.
• Make sure every part is dry before using it again.

In a humid kitchen, water left on the heating plate soon turns into crust. Wiping the plate and the bottom of the pot after every use is a small habit that keeps the sensor reading the temperature correctly.

Take the rice cooker to the dealer or the brand's authorized service center if:

• the light still does not come on even though the cord and socket are fine (Philips names a broken light as one possibility);
• the rice cooker does not switch to warm automatically (Philips names a broken temperature control as the cause);
• the rice still burns even with enough water;
• the heating plate does not get hot at all, or you suspect the heating element is faulty;
• the inner pot is dented or its coating is peeling;
• the cord, plug or body is damaged, overheats or smells burnt. The manual says not to use the cooker if the plug, cord, inner pot, sealing ring or main body is damaged.

Taking apart the thermostat or sensor, bypassing a thermal fuse and replacing the heating element are jobs for a technician. Never wedge down a switch that will not stay down: the temperature protection inside is there to keep a dry pot from heating on and on.