Boiler emits a burning smell or plastic odor during operation.

Safety first: If you smell burning plastic or see smoke, turn off power immediately and do not operate the boiler until inspected.

• Step 1 – Initial inspection: After the boiler cools, remove the front panel and look for discolored, melted, or charred wiring and components.
• Step 2 – Clean dust: Use a vacuum with a brush attachment to gently remove dust from non-electrical surfaces around the heat exchanger and burner area. Do not disturb gas train components.
• Step 3 – Check air intake: Ensure the combustion air intake is clear and not drawing in lint or debris.
• Step 4 – Inspect circulator and fan: Smell near the circulator pump and inducer motor. Overheating motors may have a strong odor and feel very hot. Replace any motor that shows signs of overheating or binding.
• Step 5 – Professional evaluation: If any wiring insulation is brittle or discolored, or if the smell persists, have a technician test current draw and replace damaged components.

Note: A mild odor may be normal on first startup of a new boiler as oils burn off, but it should dissipate quickly.