Furnace emits a burning smell or plastic smell during operation

Safety first: If smoke is visible or the smell is strong, switch off power and gas immediately and ventilate the area.

• Initial use: A slight smell on first use or after long inactivity can be normal as dust burns off. This should disappear after a few hours.
• Inspect internally: With power off and cooled, remove the cover and look for discoloured plastic, melted insulation, or foreign objects near hot surfaces.
• Check connections: Examine terminal blocks and connectors for signs of overheating or loose screws. Tighten or replace as needed.
• Motor temperatures: Feel the pump and fan housings (when off and cooled). Excessive heat may indicate impending failure and they should be replaced.
• Do not ignore persistent smell: If the smell persists, have a technician perform a full safety inspection.