How to Test a Furnace Ignitor with a Multimeter

Published: July 23, 2026 — BC Wide Home Services Ltd, doing business as BC Wide Heating & Air Conditioning — Greater Vancouver, BC

Visual Inspection First

Before testing electrically, visually inspect the ignitor. Look for: cracks in the ceramic or element, discolouration indicating overheating, or physical damage from handling. A cracked ignitor will not heat properly and must be replaced. Handle ignitors carefully — even a small crack can cause failure.

Electrical Testing

Turn off power to the furnace. Remove the ignitor (disconnect wires and mounting screws). Set multimeter to ohms (Ω). Measure across the two ignitor terminals. A good ignitor typically reads 40-200 ohms depending on the type. An open circuit (OL, infinite resistance) indicates a failed ignitor that needs replacement.

Professional Replacement Cost

Ignitor replacement: $250-450 including part and labour. DIY replacement: $20-80 for the part plus your time. If you are comfortable removing the ignitor, installation is straightforward — just handle it carefully. The ignitor is fragile — even minor contact can cause damage.

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Safety Reminder

If you smell gas, suspect carbon monoxide or believe there is an immediate danger, leave the property and contact emergency services or the appropriate gas emergency authority. Do not remain inside — exit the building immediately and call for help from outside.