What MFD capacitor do I need for my National HVAC Parts AC?

The correct replacement for National HVAC Parts model 40+10 MFD 370/440V Dual Run Capacitor — Universal AC System 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 National HVAC Parts equipment which lists the model number 40+10 MFD 370/440V Dual Run Capacitor — Universal AC System.

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.

Is this capacitor compatible with Bryant or Payne systems too?

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

National HVAC Parts

40+10 MFD 370/440V Dual Run Capacitor — Universal AC System

Name: 40+10 MFD 370/440V Dual Run Capacitor — Universal AC System
Brand: National HVAC Parts
SKU: NHVAC-CAP-RST8AN
Price: 17.99 USD
Availability: InStock

SKU: NHVAC-CAP-RST8AN Brand: National HVAC Parts

$17.99 $25.19

Order before 3PM CST — ships same day.
Standard delivery 2-5 business days. Express options at checkout.

OEM Guaranteed

Same-Day Ship

30-Day Returns

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40+10 MFD dual run capacitor for AC systems with larger fan motors requiring 10 MFD. The 40 MFD side powers the compressor, the 10 MFD side powers the condenser fan motor.

Specifications

Capacitance: 40+10 MFD (±6%)
Voltage: 370/440 VAC
Terminals: 3-prong — HERM, FAN, COM

Why would my system need a +10 instead of +5?

Larger condenser fan motors (typically 1/3 HP and above) require a 10 MFD run capacitor instead of 5 MFD. Always match the MFD value listed on your existing capacitor or on the motor nameplate.

Fitment Guaranteed — if this capacitor doesn't work in your system, we'll send the right one or refund you.

Ships same-day from Houston, TX on orders before 3PM CST.

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

Frequently Asked Questions

Does this Capacitor fit my National HVAC Parts 40+10 MFD 370/440V Dual Run Capacitor — Universal AC System?

Yes. This is the factory-specified OEM capacitor for the National HVAC Parts 40+10 MFD 370/440V Dual Run Capacitor — Universal AC System. 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 National HVAC Parts 40+10 MFD 370/440V Dual Run Capacitor — Universal AC System?

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 National HVAC Parts 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 National HVAC Parts 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.