When choosing a replacement, matching your ratings is key. A 10 MFD 440/370V capacitor can replace a 10 MFD capacitor rated at either 370 V or 440 V, as long as the shape fits your mounting bracket.
Parts with these numbers
10 MFD 440/370V Round Single Run Capacitor (Titan Pro TRCF10)
10 MFD 440/370V Oval Single Run Capacitor (Titan Pro TOCF10)
- 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 Ratings Mean
Capacitor labels show two main electrical ratings: capacitance and voltage.
Capacitance is measured in microfarads, which may be written as µF, MFD, or uF. A 10 µF rating means the part provides 10 microfarads of capacitance. This number must match the rating on your old capacitor exactly.
The voltage rating shows the highest voltage the part can handle safely. A 440/370V rating means the capacitor can handle up to 440 volts. A 440 V capacitor can replace a 370 V one, but you must never install a capacitor with a lower voltage rating than the original part.
How to Read Your Old Capacitor Label
Wipe off dirt from your old capacitor case so you can read the printed label clearly. Look for the microfarad rating, the voltage limit, and the terminal layout.
A single run capacitor powers one motor and has two terminals on top. A dual run capacitor powers two motors from one can and has three terminals labeled HERM, FAN, and C. If your old part shows only a single number like 10 µF, it is a single run capacitor. Start capacitors show a broad range, such as 88 to 108 µF, and are not the same as a run capacitor.
Round vs Oval Capacitors
Round and oval capacitors with the same ratings do the exact same job electrically. The only difference is the physical shape of the metal can.
Pick the shape that fits the metal bracket inside your unit.
- Titan Pro TRCF10 is a round single run capacitor. It measures 1.77 inches in diameter, 1.77 inches in width, and 2.17 inches in height. It replaces part numbers PRCF10, CAP-10/440R, and CR10X440R.
- Titan Pro TOCF10 is an oval single run capacitor. It measures 2.03 inches in diameter, 2.03 inches in width, 1.24 inches in depth, and 2.56 inches in height. It replaces part numbers TOC10, CAP-10/440, 45100H, and POCF10.
Signs of a Failing Capacitor
When a capacitor gets weak or stops working, the motor it supports cannot run properly. A fan that hums but will not spin is often caused by a bad capacitor rather than a bad motor.
You may also notice the outdoor fan motor moving very slowly, cutting out, or failing to start entirely when the thermostat calls for cooling.
How to confirm it fits
- Turn off the breaker and the outdoor disconnect, then confirm power is off with a tester.
- Locate the µF or MFD rating on your old part and confirm it reads 10 µF.
- Check the voltage rating on the old part to confirm it reads 370 V or 440 V.
- Check the terminals on top to ensure your old part is a single run capacitor with two terminals.
- Check whether your mounting bracket holds a round or oval can, and measure the space to ensure the new part fits.
Questions
Can a 440V capacitor replace a 370V capacitor?
Yes. Volts must be the same or higher. A 440 V capacitor can replace a 370 V capacitor, but never use a lower voltage rating.
Does it matter if I choose a round or oval shape?
Round and oval capacitors with the same ratings do the same job. You should choose the shape that fits inside your equipment mounting bracket.
What is the difference between a single run and a dual run capacitor?
A single run capacitor has two terminals and supports one motor. A dual run capacitor powers two motors from one can and has three terminals labeled HERM, FAN, and C.
How should I handle the wires during replacement?
Take a photo of every wire before removing the old part. Move the wires one at a time to the same spots on the new part.
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.