1. First, place the smart electric pressure cooker flat on the table, fill the inner pot with an appropriate amount of water, cover the lid and rotate it in place. Test the machine with power on, and at the same time clamp the clamp multimeter in the line to measure its operating current. At this time, you will see that the display on the function key panel of the electric pressure cooker displays four zeros. When the "cooking" function key is pressed, the E4 fault code will be displayed in the window after a few seconds (such as the part in the red circle in the picture). ), the multimeter reading is a few tenths of ampere, indicating that it is not working properly and the whole is in a state of protection.

2. Unplug the smart electric pressure cooker, open the lid, take out the inner pot, and turn the pot upside down on the table. Use a Phillips screwdriver to remove the fixing screws on the bottom cover and open the cover. After opening the lid, you can see the circuit part of the smart electric pressure cooker. The circuit board in the red coil in the picture is the power board of the electric pressure cooker, also called the main board. The other metal switch is called the pressure switch, which is the main component for controlling the pressure in the pot. Check the product manual. The fault code explanation E4 is a pressure system failure. Apart from the power board, the only accessories related to the pressure system of this type of pot are the pressure switch. Therefore, we first perform inspection and maintenance on the pressure switch.

3. Due to the position of the pressure switch, we must first open the plastic base of the outer ring to measure the pressure switch. First use a Phillips screwdriver to unscrew the fixing screws on the outer ring, and then separate the black base from the outer skin. With the pressure switch fully exposed to your eyes, use a multimeter to measure whether the two pins of the pressure switch have continuity. Normally it should be in a conductive state and the reading on the meter should be zero. At this time, press the switch by hand to see if the meter reading changes. If it does not change or there is no reading at all (the screen displays OL), it means that the switch is damaged and needs to be replaced. In actual maintenance, some people like to use paper or sandpaper to polish the contacts to repair the switch. Although the problem is temporarily solved, the same fault occurs again after using it a few times. This is because the contacts of the switch have been ablated and the bimetallic piece of the switch has lost its original elasticity after being used for a long time, and the pressure in the pot has also changed accordingly. If you still need to simply polish the contacts to troubleshoot , continued use may pose safety risks.

4. Unscrew the screws on the two terminals of the pressure switch, then unscrew the fixing screw in the middle of the pressure switch, and remove the pressure switch. As you can see from the picture, the pressure switch in the original pot is an old-fashioned non-adjustable pressure switch, and the screw in the middle is a fine-tuning screw for adjusting temperature changes. Due to the quality of repairs, it was replaced with a dual-adjustable pressure switch. The difference is that there is a separately adjustable screw on the front end of the pressure switch specifically for adjusting pressure.

5. Install the new pressure switch according to the reverse steps of disassembly, connect the connecting wires of the two pin terminals and tighten them. Reinstall the outer cover of the base to the machine as it is and tighten the three foot screws. At this time, the maintenance work has not been completed. Due to the transportation or manual adjustment of the pressure switch after leaving the factory, the control pressure is inaccurate. Direct use may cause safety hazards, such as excessive pressure and failure to trip, causing burnt rice or explosions. Therefore, we need to conduct actual pressure measurements to ensure that the pressure does not exceed the limit during use of the electric pressure cooker.

6. Place a small square stool upside down on the table, place the electric pressure cooker directly on top of it, put the inner pot into the pot and pour in an appropriate amount of water, cover the lid and rotate it in place. Remove the exhaust valve on the cover and use the prepared special pressure gauge to stick it on the exhaust nozzle on the cover. Turn on the power to test the machine, and connect the current clamp meter to observe the operating current. At this time, press the function key "Cooking" on the panel and the screen will no longer display E4, but the unique heating pattern will continue to rotate. Then observe that the multimeter reads 3.9 amps (this current value varies depending on the brand of pot), indicating that it has heated and is working normally. Wait for the water in the pot to boil. During this process, listen carefully to the sound of the float valve exhausting. When the float valve begins to exhaust, use a Phillips screwdriver to insert under the small stool and align it with the screw of the pressure switch at the bottom of the pot. Prepare to adjust.

7. When the float valve suddenly stops venting after a few seconds, it means that the float valve is closed and there is pressure in the pot. At this time, you should look at the pressure gauge on the lid and the clamp flow meter. reading changes.

When the pointer of the pressure gauge rises to 0.4MPa, quickly turn the screwdriver clockwise until you hear a "click" sound in the pot. Stop adjusting when the reading of the flow meter drops rapidly from 3.9 amps to a few tenths of amps. At this time, the electric pressure cooker panel display will display a countdown to maintain pressure for 10 minutes (the size of this number will vary depending on the cooker brand).

8. Cut off the power supply, take the electric pressure cooker off the stool, use a long-handled screwdriver to press the float valve to force the exhaust. After the air pressure in the pot is exhausted, remove the pressure gauge and open the lid. , take out the inner tank and snap the original exhaust valve back onto the cover. Turn the pot upside down on the table, tighten the nut on the pressure switch adjustment screw until the bottom is still, and use 704 white silicone to stick the nut and screw together. The purpose is to prevent pressure changes caused by displacement during use. At the same time, the fine-tuning screw on the pressure switch is also sealed with white silicone to prevent displacement.

9. Install the lid on the bottom of the pot as it is and tighten the screws. Turn the pot over and put it into the inner pot. Cover the lid and turn on the power. Then look at the pressure cooker panel and press the function. When the "Cooking" button is pressed, the screen returns to normal and there is a heating cycle pattern, indicating that the pot can be used normally and the repair has been successful.

Note: When the electric pressure cooker is powered on to adjust the pressure, be sure to use a screwdriver with an insulated handle, and the movement must be thin and light. Do not use force to artificially cause the switch action, otherwise the pressure will be inaccurate and the pressure must be adjusted. Avoid risk of electric shock.

E3/E4 refers to signal switch failure (ie pressure switch failure). This failure is most commonly caused by desoldering of the cable solder joints in the power supply module. This fault can be found by inspecting the solder joints in the power board and control pole. In addition, the pressure switch itself fails, or the control is extremely exposed to moisture and causes an error signal. (Note: Remember to disconnect the connecting wires at both ends when measuring the pressure switch)

1. The digital characters in the display are missing

The faulty host is the solder joint around the display Where desoldering is done, add welding and it will work.

2. When the power is on, the display does not light up, but the relay action sound can be heard. The pot has been heated and cannot be controlled.

This fault is also caused by weak soldering or desoldering of the solder joints.

3. The control is completely normal, the display is normal, but it does not heat.

(1) The relay is burned out and does not operate. You can replace it.

(2) The solder joint is desoldered and the signal cannot be transmitted - re-solder!

(3) The heating plate has been damaged and needs to be replaced with a new one.

4. Keep warm after heating for a while (the water is not turned on)

(1) The pressure switch is malfunctioning (blocked) but the display panel does not display an error signal, and the circuit is interrupted here.

(2) The solder joints are desoldered and the signals are disordered.