What MFD capacitor do I need for my Lennox AC?

The correct replacement for Lennox model OEM Lennox Dual Run Capacitor 35+7.5 MFD 370V Round — R100335-49 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 Dual Run Capacitor 35+7.5 MFD 370V Round — R100335-49.

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.

Lennox

OEM Lennox Dual Run Capacitor 35+7.5 MFD 370V Round — R100335-49

Name: OEM Lennox Dual Run Capacitor 35+7.5 MFD 370V Round — R100335-49
Brand: Lennox
SKU: LNX-R100335-49
Price: 18.95 USD
Availability: InStock

SKU: LNX-R100335-49 Brand: Lennox

$18.95 $24.95

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The Lennox R100335-49 is a genuine OEM dual run capacitor rated 35+7.5 MFD, 370V in a round case. It provides the starting and running torque for both the compressor (35 MFD side) and the condenser fan motor (7.5 MFD side), keeping your Lennox air conditioner or heat pump running smoothly and at its designed efficiency.

Common Failure Symptoms

When the R100335-49 falls out of spec, the compressor or fan motor may hum without starting, the condenser fan may spin slowly, and the unit may trip its breaker or blow warm air. A bulging, domed, or leaking capacitor top, along with reduced cooling and higher energy bills, indicates the part should be replaced.

Why OEM Matters

The factory-spec R100335-49 matches the exact 35+7.5 MFD dual rating, 370V tolerance, and round footprint your Lennox control box and mounting bracket were built around. Aftermarket capacitors with the wrong capacitance or voltage overheat, fail prematurely, and can damage the compressor. Genuine OEM protects your investment and preserves rated 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 Dual Run Capacitor 35...

$18.95

Frequently Asked Questions

Does this Capacitor fit my Lennox OEM Lennox Dual Run Capacitor 35+7.5 MFD 370V Round — R100335-49?

Yes. This is the factory-specified OEM capacitor for the Lennox OEM Lennox Dual Run Capacitor 35+7.5 MFD 370V Round — R100335-49. 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 Dual Run Capacitor 35+7.5 MFD 370V Round — R100335-49?

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.