Lennox Furnace Capacitor Parts

Lennox Furnace Run Capacitor Parts

The run capacitor is the silent workhorse of your Lennox furnace — it stores and releases electrical energy to start the blower motor and inducer motor on every heating cycle. When a capacitor fails, you'll notice the blower won't start, runs slowly, or hums without spinning. A failed capacitor often saves you from a more expensive motor replacement, so catching it early is key.

Lennox furnace capacitors come in specific microfarad (µF) ratings — 5µF, 10µF, 20µF, or dual-run combinations. Matching the exact rating is critical; even a 10% variance can damage your motor or prevent proper startup. Always check your model number and the old capacitor label before ordering.

• Blower motor won't start or runs slowly: capacitor has lost capacitance; humming sound with no fan movement
• Furnace runs but no airflow: run capacitor failed; motor receives insufficient startup torque
• Inducer motor hums but doesn't spin: capacitor issue combined with draft inducer startup failure
• Capacitor bulging or leaking fluid: immediate replacement needed; fire/safety risk
• Furnace cycles on and off repeatedly: weak capacitor causes thermal overload protection to trip

Find your Lennox furnace capacitor by entering your model number above. Repair Clinic carries OEM Lennox capacitors for Dave Lennox Signature, Elite, and Merit series furnaces — exact replacements that restore full motor performance.

Lennox Furnace Capacitor FAQs

What does a furnace capacitor do?

The run capacitor stores electrical energy and releases it in a quick pulse to start the blower or inducer motor. Think of it as a temporary energy bank — without it, the motor won't have enough torque to overcome startup resistance. As capacitors age, they lose the ability to hold and release that charge, causing sluggish or failed starts.

How do I know if my Lennox capacitor is bad?

A bad capacitor shows itself through these signs: the blower motor hums but doesn't spin, the motor runs very slowly, or it won't start at all. You may also see the capacitor physically bulging, leaking fluid, or burnt. The safest test is to check continuity with a multimeter set to the capacitance setting — any reading below the rated µF on the label means replacement.

What's the difference between a run capacitor and a start capacitor?

Lennox furnaces use run capacitors (which stay in the circuit continuously) rather than start capacitors (which drop out after motor startup). Run capacitors are smaller and designed for continuous duty. Always match the exact type — using a start capacitor in a run application will overheat and fail quickly.

Do I need to match the exact microfarad rating?

Yes. Microfarad (µF) rating must be exact or within manufacturer tolerance (usually 5 to 10%). A capacitor rated 10µF cannot safely replace a 20µF unit — it will undersupply the motor. Conversely, oversizing can cause overcurrent and damage. Voltage rating can be equal or higher (e.g., a 440V capacitor can replace a 370V), but µF must match precisely. Your model number lookup confirms the exact capacitor for your Lennox furnace.

Order Lennox Furnace Capacitor Parts Online

Purchasing Lennox furnace capacitor parts online is made simple and efficient with Repair Clinic. With our No-Hassle 365-Day Returns, you can return any uninstalled part within a year of purchase for a full refund, ensuring peace of mind with every order. Our Price Match Guarantee means you'll always get genuine OEM replacement parts at the best price, as we match any competitor's offer. Easily search for Lennox furnace capacitors by part number or model number for accurate results. We offer same-day shipping for orders placed by 9:00 PM ET, ensuring you receive your parts quickly. Whether you're a homeowner or a technician, our full inventory and exceptional customer service make Repair Clinic your go-to source for furnace replacement parts. Visit our replacement parts page to browse our extensive inventory and get your Lennox furnace running smoothly again.

Lennox Furnace Model Number: Where to Look

On Lennox furnaces, look for the model number on the blower compartment door, usually on a manufacturer label. If it is not there, check inside the front access panel or near the gas valve. The model number identifies the entire furnace, not just its capacitor or another individual part, so copy every letter, number, and hyphen exactly as shown. Enter that information in the model number search, and the catalog will narrow to parts matched to your unit. This helps you compare the full selection of Lennox furnace parts without relying on appearance or guessing at specifications. You order with confidence knowing the fit is right.