What MFD capacitor do I need for my Lennox AC?

The correct replacement for Lennox model OEM Lennox Run Capacitor 45 MFD 440V Round — Y9641 is this exact part. It is the factory-specified replacement with exact OEM specifications. Using a part with different specifications can cause equipment damage or void your warranty. You can verify this by checking the data plate on your Lennox equipment which lists the model number OEM Lennox Run Capacitor 45 MFD 440V Round — Y9641.

My AC hums but will not start. What part do I need?

An AC that hums but will not start is the classic symptom of a failed capacitor. The capacitor provides the electrical boost needed to start the compressor and fan motors. When it fails, you hear the hum of the motor trying to start but it cannot overcome inertia. Other symptoms include the fan spinning slowly, the AC cycling on and off rapidly, or a visibly swollen or leaking capacitor. Replacement cost: $15 to $80 for the part, DIY in 30 minutes.

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Lennox

OEM Lennox Run Capacitor 45 MFD 440V Round — Y9641

Name: OEM Lennox Run Capacitor 45 MFD 440V Round — Y9641
Brand: Lennox
SKU: LNX-Y9641
Price: 18.95 USD
Availability: InStock

SKU: LNX-Y9641 Brand: Lennox

$18.95 $24.95

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The genuine OEM Lennox Y9641 is a 45 MFD, 440V round run capacitor, made in the USA to precise factory tolerances. It supplies the continuous charge that your compressor and condenser fan motor need to start reliably and run efficiently, holding steady torque and reducing the electrical strain that wears out motor windings over time.

A weakening Y9641 shows familiar warning signs: the outdoor unit hums but won't start, the fan or compressor struggles to spin, the system short-cycles or trips the breaker, cooling output falls, and the capacitor casing may bulge or leak. Since capacitance declines gradually, replacing the part at the first symptom protects the far more expensive motor it drives.

OEM is the right call for Lennox systems. The 45 MFD capacitance and 440V rating of the Y9641 are matched to the equipment's engineered specifications, while generic replacements can drift out of spec and shorten motor life. This USA-made factory part ensures an exact fit and rated, reliable performance.

Shipping Information

Orders placed before 3PM CST ship same business day
Standard delivery: 2-5 business days
Express shipping available at checkout
Free shipping on orders over $75
Tracking number emailed upon shipment

Return Policy

30-day returns on unused parts in original packaging
Electrical parts (capacitors, contactors, control boards) are final sale once installed
Email info@nationalhvacparts.com to initiate a return
Refunds processed within 5-7 business days

OEM Lennox Run Capacitor 45 MFD ...

$18.95

Frequently Asked Questions

Does this Capacitor fit my Lennox OEM Lennox Run Capacitor 45 MFD 440V Round — Y9641?

Yes. This is the factory-specified OEM capacitor for the Lennox OEM Lennox Run Capacitor 45 MFD 440V Round — Y9641. It is a direct drop-in replacement that fits without modification. Always verify the model number on your equipment nameplate before ordering.

How do I replace the capacitor on my Lennox OEM Lennox Run Capacitor 45 MFD 440V Round — Y9641?

Difficulty: Easy (20–30 min)
Step 1: Turn off power at breaker. Step 2: Open condensing unit panel. Step 3: Photograph the old capacitor wiring (Common/Herm/Fan). Step 4: Discharge old capacitor with insulated screwdriver. Step 5: Disconnect and remove old capacitor. Step 6: Mount new capacitor, reconnect wires to matching terminals. Step 7: Close panel, restore power, test. Tools: screwdriver, needle-nose pliers.

My AC hums but won’t start. What part do I need?

An AC that hums but won’t start is the classic symptom of a failed capacitor. The capacitor provides the electrical boost to start the compressor. When it fails, you hear humming but the motor can’t overcome inertia. Other symptoms: fan spinning slowly, AC cycling on/off rapidly, or a visibly swollen capacitor. Fix: replace capacitor ($15–$80 DIY, 30 min).

Is this capacitor compatible with Bryant or Payne too?

Many Lennox parts are cross-compatible with Bryant and Payne since all three brands are manufactured by Carrier Global Corporation. The same physical part is often used across brand labels with different model numbers. To verify: check your Bryant or Payne equipment service manual for cross-compatible part numbers, or email info@nationalhvacparts.com with your model number.

Should I use OEM or aftermarket for my Lennox capacitor?

OEM strongly recommended. OEM capacitors have ±6% MFD tolerance vs aftermarket ±10%. The looser tolerance causes motor winding stress, higher temps, and shorter compressor life. Price difference is only $10–$20 — OEM is the clear value choice.

How fast does National HVAC Parts ship?

Orders placed before 3:00 PM CST ship the same business day. Standard delivery is 2–5 business days anywhere in the continental United States. Express shipping available at checkout. We ship from Houston, TX to all 50 states. 30-day return policy on all parts.

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OEM Lennox Run Capacitor 45 MFD 440V Round — Y9641

Shipping Information

Return Policy

Frequently Asked Questions