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Home / 55 MFD 370/440V Round Run Capacitor —...
55 MFD 370/440V Round Run Capacitor — Universal AC Motor Replacement
National HVAC Parts

55 MFD 370/440V Round Run Capacitor — Universal AC Motor Replacement

SKU: NHVAC-CAP-AKU2BT Brand: National HVAC Parts
$16.99 $23.79

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

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55 MFD single run capacitor rated 370/440V for residential and light commercial HVAC systems. This is the motor run capacitor — it stays in the circuit continuously while the motor operates, providing the phase shift needed for single-phase motor rotation.

Direct replacement for any system requiring a 55 MFD run capacitor. The 440V rating works in both 370V and 440V applications — the voltage rating is the maximum, not the operating voltage.

Specifications

  • Capacitance: 55 MFD (±6%)
  • Voltage: 370/440 VAC 50/60Hz
  • Shape: Round aluminum canister
  • Terminals: 2-prong push-on (top mount)
  • Operating temp: -40°F to +185°F
  • UL recognized component

Common Applications

Compressor motors on 3-5 ton systems, large blower motors

Frequently Asked Questions

My existing capacitor is rated 370V — can I use this 440V?

Yes. A 440V capacitor safely replaces a 370V capacitor of the same MFD. The voltage rating is the maximum, not operating voltage. Using a higher-rated capacitor is perfectly safe and often recommended for longer life.

How do I test if my capacitor is bad?

Use a multimeter with capacitance mode. Disconnect power, discharge the cap, then measure. A good 55 MFD capacitor should read between 51.7 and 58.3 MFD (within 6%). If it reads significantly low, it's weak and causing motor problems. If the top is bulging or leaking oil, replace immediately.

Can I use a slightly different MFD value?

Stay within 6% of the original value. A 55 MFD cap should not be replaced with anything below 52 or above 58 MFD. Using the wrong value causes motor overheating, reduced efficiency, and potential compressor damage.

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 55 MFD 370/440V Round Run Capacitor — Universal AC Motor Replacement?
Yes. This is the factory-specified OEM capacitor for the National HVAC Parts 55 MFD 370/440V Round Run Capacitor — Universal AC Motor Replacement. 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 55 MFD 370/440V Round Run Capacitor — Universal AC Motor Replacement?
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.
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