After powering on the digital hot plate and turning on the heating switch but the unit fails to heat up, the 4 main potential causes are listed below:

1. Damaged heating element (most probable)
2. Faulty heating switch
3. Damaged relay
4. Defective temperature controller

Open the bottom cover of the heating plate and perform inspection in the following sequence. Warning: Pay attention to electric shock hazards during live testing.

1. Test Heating Tube
   Cut off all power supply first. Set the multimeter to resistance mode. Disconnect the wires of the heating tube and test each branch separately. Normal resistance ranges from tens to around 200 ohms. Infinite resistance or near-zero resistance indicates a broken heating tube; replace it.
2. Test Heating Switch
   Disconnect power first. Switch multimeter to continuity mode. Toggle the power switch to ON position. Measure the switch terminals. If both circuits conduct, the switch works normally; otherwise replace the switch.
3. Test Solid State Relay
   Power on the device with caution against electric shock. Turn on heating switch. If the indicator light of SSR lights or flashes, the input side is normal. If no light, measure terminals 3 and 4 of SSR for 12VDC. No 12VDC means defective temperature controller. Switch multimeter to 750VAC range, measure terminals 1 and 2 of SSR. Constant 220VAC without change means the SSR is damaged and needs replacement.
4. Test Temperature Controller
   Power on the unit and turn on heating. Check if the temperature display works normally. Set multimeter to 20VDC DC range and measure terminals 3 and 4 of SSR. Absence of 12VDC output indicates the temperature controller is faulty and needs replacement.

If your team has technical staff, self-inspection and repair can save time and cost. If the fault cannot be fixed, please contact our factory after-sales service for support.

• Always disconnect power before disassembling the equipment for maintenance.
• Live voltage measurement must be operated by professional technicians with insulation protection.
• Do not continue operating the device if any electrical component is damaged.