Tesy digital heater shows E07; unit may heat uncontrollably or not at all.

Safety first: Switch off the breaker and verify no voltage. This fault can cause overheating—do not continue using the heater until resolved.

Steps:

• Visual inspection of board: Remove the cover and inspect the control board. Look for burned areas near the power relay or triac (often heat-sink mounted).
• Check for stuck relay: With power OFF, gently tap the relay body. If contacts are welded, this will not fix it but may confirm mechanical failure.
• Measure element voltage: With the heater commanded OFF (if possible) and power ON, carefully measure voltage at the element terminals. If full mains voltage is present when it should be off, the triac/relay is stuck ON.
• Replace control board or power module: On most Tesy models, the triac/relay is part of the main board. Replace the entire electronic control board or power module rather than attempting component-level repair.
• Re-test: After replacement, verify that the heater switches the element ON/OFF correctly and that E07 is cleared.

Warning: Working around live mains requires expertise. If you are not trained, have a qualified technician perform the live voltage tests and board replacement.