What MFD capacitor do I need for my Carrier AC?

The correct replacement for Carrier model PH4ZNA042000AA 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 Carrier equipment which lists the model number PH4ZNA042000AA.

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 Carrier 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.

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OEM Carrier Dual Run Capacitor 45+5 MFD for PH4ZNA042000AA

Name: OEM Carrier Dual Run Capacitor 45+5 MFD for PH4ZNA042000AA
Brand: Carrier
SKU: CARRIE-PH4ZNA042000AA-CAPACITOR-P291-4554RS
Price: 30.00 USD
Availability: InStock

SKU: CARRIE-PH4ZNA042000AA-CAPACITOR-P291-4554RS Brand: Carrier

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OEM Carrier Dual Run Capacitor 45+5 MFD for Model PH4ZNA042000AA

This is the factory OEM dual run capacitor (part number P291-4554RS) for the Carrier PH4ZNA042000AA heat pump system. The dual run capacitor serves a critical role in your unit's electrical system — it stores and releases the precise electrical charge needed to start and continuously run both the compressor and the condenser fan motor. When this capacitor degrades or fails, you'll typically notice symptoms such as a loud humming or buzzing with no motor movement, the system attempting to start but quickly shutting down, the condenser fan spinning slowly or not at all, or the compressor failing to engage entirely.

Specs: 45+5 MFD (microfarad) | Round case design | Factory-matched capacitance tolerance | Rated for use in Carrier PH4ZNA042000AA heat pump applications
OEM vs Generic: As an OEM part, the P291-4554RS meets Carrier's exact factory tolerances (typically ±3% MFD), ensuring proper motor start torque and run performance. Generic or aftermarket capacitors often carry a ±10% tolerance, which can accelerate wear on the compressor and fan motor bearings over time.
Install Difficulty: 2/5 — A dual run capacitor replacement is one of the more accessible HVAC repairs for a qualified technician. Always discharge the capacitor fully before handling terminals. Tools needed: 1/4" nut driver, insulated needle-nose pliers, and a multimeter to verify discharge. Photograph all wiring connections before disconnecting anything.
Warranty: Backed by a 1-year OEM manufacturer warranty. In-stock orders ship same business day from our warehouse.

Compatibility: This part is engineered specifically for the Carrier PH4ZNA042000AA heat pump. Always cross-reference the MFD rating and voltage specification on your unit's data plate before ordering to confirm fitment. Not sure? Our HVAC parts specialists are available to verify compatibility before you buy — no guesswork required. Order today and get same-day shipping on all in-stock parts.

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 $99
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 Carrier Dual Run Capacitor 4...

$30.00

Frequently Asked Questions

Does this Capacitor fit my Carrier PH4ZNA042000AA?

Yes. This is the factory-specified OEM capacitor for the Carrier PH4ZNA042000AA. 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 Carrier PH4ZNA042000AA?

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 Carrier 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 Carrier 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 Carrier Dual Run Capacitor 45+5 MFD for PH4ZNA042000AA

OEM Carrier Dual Run Capacitor 45+5 MFD for Model PH4ZNA042000AA

Shipping Information

Return Policy

Frequently Asked Questions