Heater does not turn on after a power outage; no lights or display.

Safety first: Ensure power is off before opening the electrical compartment. Surges can leave components in an unsafe state.

Steps:

• Check external supply: Confirm the breaker is ON and other appliances on the same circuit work.
• Inspect internal fuse: Some Tesy models have an internal fuse on the control board. Check and replace with the exact same rating if blown. Investigate cause of blowing.
• Look for surge damage: Burn marks or a burnt smell on the board indicate surge damage. Replace the electronic control board.
• Secure terminals: Tighten mains terminal screws and check for loose wires.
• Surge protection: After repair, consider installing a surge protector on the heater’s supply.