When looking for a replacement, matching your ratings is simple. The microfarad rating must match your old unit exactly, while the voltage rating can be the same or higher.
Parts with these numbers
50+5 MFD 440/370V Round Dual Run Capacitor (Bluefin CPDRR1-505)
50+5 MFD 440/370V Round Dual Run Capacitor (Titan Pro TRCFD505)
50+5 MFD 440/370V Oval Dual Run Capacitor (Titan Pro TOCFD505)
- µF (MFD): must be the same, like 45/5
- Volts: same or higher (440 can replace 370)
- Shape: round or oval, to fit the bracket
What the 50/5 MFD and 440/370V Numbers Mean
Capacitor ratings show two key electrical values: capacitance and voltage. Capacitance is measured in microfarads, which may be printed as MFD, uF, or µF. A dual run capacitor lists two numbers separated by a slash or a plus sign.
On a 50/5 capacitor, the higher number (50) powers the compressor. The lower number (5) powers the outdoor fan motor. You must match these microfarad numbers to your old part.
The voltage rating shows the maximum electrical tension the part can handle. A 440V rating can safely replace a 370V part, but you can never use a lower voltage rating than the original.
How to Read the Label and Terminals
Look at the printed label on your old capacitor. You will see markings like 50+5 µF or 50/5 MFD followed by 370V, 440V, or 440/370V.
Dual run capacitors feature three terminal posts on top, each marked with stamped letters. These letters show where each wire connects.
- HERM connects to the compressor.
- FAN connects to the outdoor fan motor.
- C connects to the common line.
Comparing Shapes and Listed Parts
Round and oval capacitors with the same ratings do the same electrical job. You only need to choose the shape that fits your unit's mounting bracket.
The Bluefin CPDRR1-505 is a round dual run capacitor rated at 50 + 5 µF and 440/370V.
The Titan Pro TRCFD505 is a round dual run capacitor rated at 50 + 5 µF and 440/370V. It replaces part numbers CAP-50/5/440R and CD50-5X440R.
The Titan Pro TOCFD505 is an oval dual run capacitor rated at 50 + 5 µF and 440/370V. It replaces part numbers POCFD505 and CD50-5X440.
Common Signs of a Failed Capacitor
When a dual run capacitor fails, the motors connected to it lose the push needed to start. A fan that hums but will not spin is often a bad capacitor, not a bad motor.
A failing capacitor might also stop your outdoor compressor from starting, which stops the system from cooling your home. Take a photo of every wire before removing the old part so you can move wires one at a time to the same spots.
How to confirm it fits
- Turn off power at the breaker and the outdoor disconnect, then discharge the old capacitor.
- Read the capacitance rating on the old label. It must read 50/5 MFD, 50+5 MFD, or 50+5 µF.
- Check the voltage rating on the old part. It must read 370V, 440V, or 440/370V.
- Inspect the case shape to see if your mounting bracket requires a round or oval can.
- Verify that the capacitor has three top terminals labeled HERM, FAN, and C.
Questions
Can I use a 440V capacitor to replace a 370V capacitor?
Yes. A 440V capacitor can safely replace a 370V capacitor. Voltage must be the same or higher, but you must never go lower.
Does the shape of the capacitor change how it works?
No. Round and oval capacitors with the same ratings do the same job. Pick the shape that fits your equipment bracket.
What do the three terminals on a dual run capacitor mean?
They are labeled HERM, FAN, and C. HERM connects to the compressor, FAN connects to the outdoor fan, and C connects to the common line.
Can I replace a 50/5 MFD capacitor with a 45/5 MFD capacitor?
No. The capacitance value must match the old part exactly. You must use a 50/5 MFD capacitor.
Related guides
Brand names and part numbers are used only to show fit. HVAC Fitter is not affiliated with, authorized by, or endorsed by any equipment maker. If you are not sure a repair is safe for you, call a licensed HVAC technician.