Heater shows E17 and may continue operating at reduced performance or shut down intermittently.

Safety: Turn off power before inspecting wiring. Only qualified personnel should measure live currents.

• Check breaker and wiring size: Confirm that the circuit breaker and supply wiring meet the minimum requirements in the installation manual for your model.
• Inspect connections: Tighten all main power terminals and check for discoloration or heat damage at lugs and busbars.
• Measure voltage under load (advanced): With the unit operating (qualified person only), measure supply voltage. Significant drops under load may indicate undersized wiring or supply issues.
• Reduce load: Temporarily lower the set temperature or limit maximum power (if your model allows) and see if E17 stops occurring.
• Professional diagnosis: If wiring and supply are correct, internal power electronics may be overheating or failing. Have a technician evaluate the power board and cooling path.