What MFD capacitor do I need for my Lennox AC?

The correct replacement for Lennox model OEM Lennox Single Run Capacitor — 22W78 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 Single Run Capacitor — 22W78.

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 Single Run Capacitor — 22W78

Name: OEM Lennox Single Run Capacitor — 22W78
Brand: Lennox
SKU: LNX-22W78
Price: 18.95 USD
Availability: InStock

SKU: LNX-22W78 Brand: Lennox

$18.95 $24.95

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The 22W78 is a genuine OEM Lennox single run capacitor. A run capacitor stores and releases electrical energy to provide the continuous phase shift a single-phase motor needs to start and run efficiently. In your Lennox condenser or air handler, this capacitor supports the compressor or fan motor, keeping current draw in check and the motor running at its rated torque and speed.

Common failure symptoms: A hard-starting or humming motor that won't spin, a condenser fan that needs a push to start, warm air from the supply registers, tripped breakers, or a compressor that clicks on and off. A bulged, leaking, or swollen capacitor top is a clear sign of failure — capacitors weaken over time from heat and electrical cycling and are one of the most common HVAC service replacements.

Why OEM matters: Capacitance (µF) and voltage ratings must match the motor's design. An undersized or mismatched capacitor causes overheating, reduced efficiency, and premature motor burnout. Installing the exact OEM 22W78 capacitor guarantees the correct microfarad and voltage rating for your Lennox unit, protecting the motor and restoring full 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 Single Run Capacitor ...

$18.95

Frequently Asked Questions

Does this Capacitor fit my Lennox OEM Lennox Single Run Capacitor — 22W78?

Yes. This is the factory-specified OEM capacitor for the Lennox OEM Lennox Single Run Capacitor — 22W78. 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 Single Run Capacitor — 22W78?

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 Single Run Capacitor — 22W78

Shipping Information

Return Policy

Frequently Asked Questions