XPARTCO XPDC40X5-450R Dual Run Capacitor (40/5 MFD, 450V, Round)
The XPARTCO XPDC40X5-450R is a universal dual run capacitor for central air conditioners, heat pumps, and condensing units. A run capacitor works alongside a single-phase AC motor to keep it running efficiently once it's started, boosting torque and correcting the phase of the current feeding the motor's windings. This is a dual capacitor, meaning it combines two separate capacitors — one for the compressor, one for the condenser fan motor — into a single three-terminal can, which is why nearly every residential outdoor AC unit uses exactly this style of component to run both motors from one part.
Rated 40 MFD for the compressor circuit and 5 MFD for the fan motor circuit, at 450VAC, in a round aluminum can housing. Because a capacitor's voltage rating is a ceiling rather than a fixed match, this 450V-rated capacitor can safely replace an original capacitor rated 370V or 440V — going higher on voltage is always safe, going lower is not. Over time, the dielectric material inside a run capacitor breaks down from heat cycling and electrical stress, causing it to lose capacitance or fail outright. A failing dual capacitor produces a very recognizable set of symptoms: the outdoor unit hums but the compressor or fan won't start, the fan spins slowly or needs a manual push to get going, the system trips the breaker, or the capacitor can itself is visibly bulging, domed, or leaking oily residue at the top.
Quick Answer
The XPARTCO XPDC40X5-450R Dual Run Capacitor fixes central air conditioners and heat pumps where the outdoor unit hums but won't start, the compressor or fan motor won't run, the fan spins slowly or needs a manual push, the breaker trips, or the capacitor can is visibly bulged or leaking. 40 MFD (compressor) + 5 MFD (fan) dual capacitor, 450VAC, round, 3-terminal. Universal fit for equipment originally speced at 370V or 440V, since a higher voltage rating is always a safe upgrade. Capacitors store a dangerous electrical charge even after power is disconnected — always discharge before handling.
Common Problems This Part Fixes
Outdoor AC unit hums but the compressor won't start
Condenser fan won't spin, or spins slowly and needs a manual push to get going
System trips the breaker shortly after starting
AC blows warm air because the compressor isn't running
Repeated clicking sound from the contactor as it tries and fails to start the motor
Capacitor can visibly bulging, domed on top, or leaking oily residue
System that used to start slowly and has now stopped starting altogether
Burning smell from the outdoor unit's electrical compartment
Cross Reference Information
Part numbers can change over a product's lifecycle as manufacturers update designs or release new appliance models. For your convenience, we've included any known superseded, alternate, or cross-reference part numbers that match this item.
Replaces Part Numbers
XPDC40X5-450R
This is a universal component rather than a single-manufacturer part, so the specific OEM number your HVAC system's label references will vary by brand (Goodman, Trane, Carrier, Rheem, York, Lennox, Amana, and others). This capacitor is a correct replacement for any dual run capacitor matching the 40 MFD / 5 MFD rating with a voltage rating of 450V or lower. If you have your original part number, contact our support team and we will verify compatibility before you order.
Compatibility
This dual run capacitor is a universal replacement compatible with central air conditioners, heat pumps, and condensing units across all major HVAC brands, wherever the original capacitor is rated:
40 MFD (compressor) + 5 MFD (fan motor)
370V, 440V, or 450V (this capacitor's 450V rating exceeds and safely replaces either lower rating)
Round can shape with 3 terminals
Note: The MFD (microfarad) rating must match your original capacitor exactly on both sides — do not substitute a different MFD value for either the compressor or fan side. Voltage rating, on the other hand, can be equal to or higher than the original (450V safely replaces 370V or 440V), but never lower. Can shape (round vs. oval) affects only physical fit inside your unit's electrical compartment, not performance. If you're unsure of your original capacitor's specifications, they're printed directly on its can — contact our support team if you'd like help confirming compatibility.
Key Features
Universal dual run capacitor — supports both the compressor and condenser fan motor from one component
40 MFD compressor rating + 5 MFD fan motor rating in a single 3-terminal can
450VAC rating — a safe upgrade replacement for equipment originally speced at 370V or 440V
Round aluminum can construction
Resolves "hums but won't start," "fan spins slowly," "trips the breaker," and "bulging or leaking can" symptoms caused by capacitor failure
1/4" quick-connect terminals for a direct plug-on fit to standard HVAC wiring
50/60Hz rated
Safety approved: CQC, VDE, TÜV, and CL; built to GB/T 3667 and EN 60252 standards
Built to meet or exceed industry-standard specifications for this capacitor class
Product Specifications
Part Number
XPDC40X5-450R
Part Type
Dual Run Capacitor
Condition
New — Universal Replacement Part
Capacitance — Compressor
40 MFD (µF)
Capacitance — Fan Motor
5 MFD (µF)
Voltage Rating
450VAC
Shape
Round
Terminals
3 (1/4" quick-connect)
Frequency
50/60 Hz
Tolerance
±5%
Construction Type
Polypropylene film capacitor
Operating Temperature Range
-40°C to 70°C (-40°F to +158°F)
Safety Approvals
CQC, VDE, TÜV, CL
Approval Standard
GB/T 3667, EN 60252
Application
Central Air Conditioners, Heat Pumps, Condensing Units
Quantity
1 dual run capacitor
Compatible Brands
Universal — all major HVAC brands
Installation Notes
⚠️ Danger — Capacitors Store A Dangerous Electrical Charge Shut off power to the outdoor unit at the disconnect box and at the breaker before beginning. A capacitor stores an electrical charge even after power has been disconnected, and that charge can deliver a serious or fatal shock. Before touching any terminal, discharge the capacitor by shorting each pair of terminals together (C-to-Fan, C-to-Herm, and Fan-to-Herm) using an insulated-handle screwdriver, or by using a proper capacitor discharge tool with a resistor. Never short the terminals with a bare metal tool held with your bare hand. If you are not fully comfortable performing a capacitor discharge safely, have a qualified HVAC technician replace this part instead.
⚠️ Photograph The Wiring Before Disconnecting — Match Terminals Exactly Wear work gloves and safety glasses. After confirming the capacitor is fully discharged, photograph the wiring on the old capacitor's terminals before disconnecting anything — dual capacitors are labeled C (Common), Herm or Comp (compressor/hermetic), and Fan, and getting a wire on the wrong terminal can damage the new capacitor or the motor it feeds. Note which terminal each wire came from, or label them individually with tape. Remove the mounting strap or bracket holding the old capacitor in its housing, and disconnect each wire from its terminal. Install the new XPDC40X5-450R in the same mounting position, secure it with the strap or bracket, and reconnect each wire to the matching terminal (C, Herm, and Fan) exactly as labeled. Double-check every connection before restoring power. Restore power at the breaker and disconnect box, and confirm the compressor and fan both start promptly and run smoothly. Tools needed: insulated-handle screwdriver or capacitor discharge tool, nut driver, work gloves, safety glasses.
Frequently Asked Questions
My AC unit hums but won't start. Is this the capacitor?
It's one of the most common causes of exactly that symptom. A run capacitor gives the compressor or fan motor the extra push needed to start turning; without it, the motor can draw power and hum in place without ever actually starting to spin. If you can see the capacitor can and it looks bulged, domed on top, or is leaking a brown oily residue, that's strong visual confirmation of failure.
Can I use a 450V capacitor to replace my old 370V or 440V one?
Yes. Voltage rating is a ceiling, not an exact match requirement — a capacitor rated for a higher voltage than your original will work safely and often lasts longer under the same electrical stress. What you cannot do is go the other direction: never install a capacitor with a lower voltage rating than your original, since that risks premature failure or the capacitor breaking down under normal operating conditions.
Does the round vs. oval shape matter?
Only for physical fit inside your unit's electrical compartment — it has no effect on electrical performance. If your unit's mounting bracket or available space is sized for a round can, use a round capacitor; if it's sized for an oval can, use an oval one. The MFD and voltage ratings are what matter electrically, not the shape.
The fan spins if I give it a push, but won't start on its own. What does that mean?
This is a classic sign of a weak or failing capacitor — it may still have enough charge to keep the motor running once it's already spinning, but not enough to provide the initial starting torque. This is a strong signal to replace the capacitor before it fails completely and leaves you with no cooling at all.
Is this a genuine OEM part?
This is a universal replacement part rather than a brand-specific OEM part. Because dual run capacitors are a standardized component defined by their electrical specifications rather than their manufacturer, this capacitor is a correct replacement for any unit's original capacitor that shares the same 40/5 MFD, 450VAC, round dual run capacitor rating — regardless of which HVAC brand originally installed it.
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