When a run capacitor weakens or stops working, the motor it powers might struggle to start or stop running entirely. Replacing a bad capacitor is a straightforward repair when you match the right ratings.
Parts with these numbers
7.5 MFD 440/370V Round Single Run Capacitor (Titan Pro TRCF7.5)
7.5 MFD 440/370V Oval Single Run Capacitor (Titan Pro TOCF7.5)
- 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
Understanding 7.5 MFD and 440/370V Ratings
Capacitor labels feature two main electrical ratings: capacitance and voltage. Capacitance is measured in microfarads, which may be printed as MFD, uF, or µF. A 7.5 MFD capacitor stores a specific amount of electrical energy designed for the motor it supports. This number must always match your old part.
Voltage shows the maximum electrical tension the capacitor can safely handle. A 440/370V rating means the capacitor handles up to 440 volts. A 440 V capacitor can safely replace a 370 V capacitor, but you must never use a lower voltage rating than the original component.
How to Read the Label on Your Old Capacitor
Before you remove any wires, wipe the metal case clean to read the factory printing. Take a clear photo of the label and all connected wires so you know where each wire belongs.
Look for the capacitance rating first. A single run capacitor will show just one number, such as 7.5 µF, and it will feature two terminals on top. If you see two numbers separated by a slash, such as 45/5, that is a dual run capacitor with three terminals.
Next, check the voltage rating. You will typically see 370V, 440V, or 440/370V. Make sure the replacement voltage rating is the same or higher.
Choosing Between Round and Oval Shapes
Round and oval capacitors with identical electrical ratings perform the exact same job. The primary difference is the physical shape and dimensions, which determine how the part mounts inside the cabinet.
You should pick the shape that fits your unit's mounting bracket and allows the wires to reach comfortably without stretching.
- Round single run: Titan Pro TRCF7.5 is 1.57 inches in diameter, 1.57 inches wide, and 2.17 inches tall. It replaces TRC7.5, CAP-7.5/440R, and CR7.5X440R.
- Oval single run: Titan Pro TOCF7.5 measures 2.03 inches wide, 1.24 inches deep, 2.03 inches in diameter, and 2.17 inches tall. It replaces TOC7.5, CAP-7.5/440, 37075H, and POCF7.5.
Signs of a Failing Run Capacitor
When a run capacitor goes bad, the motor connected to it fails to receive the steady phase shift it needs. A fan that hums but will not spin is often a bad capacitor, not a bad motor.
Physical inspection can also reveal trouble. Weak or failed capacitors often show bulging tops, leaking fluid, or swollen metal casings. If the motor fails to turn or stops during operation, testing the capacitor is an essential early troubleshooting step.
How to confirm it fits
- Check the capacitance rating on the old case. It must read 7.5 µF, 7.5 MFD, or 7.5 uF.
- Check the voltage rating on the original part. It should read 370V, 440V, or 440/370V.
- Verify the terminal count. A single run capacitor has two terminals, while a dual run capacitor has three terminals labeled HERM, FAN, and C.
- Measure your existing mounting bracket and pick the round or oval shape that fits your cabinet space.
- Confirm that the replacement part number matches or replaces the number printed on your existing part.
Questions
Can I replace a 370V capacitor with a 440V capacitor?
Yes. A 440 V capacitor can safely replace a 370 V capacitor. Voltage must be the same or higher, never lower.
Does the physical shape affect how the capacitor works?
No. Round and oval capacitors with the same electrical ratings do the same job. You only need to pick the shape that fits inside your mounting bracket.
What is the difference between a single run capacitor and a dual run capacitor?
A single run capacitor powers one motor and has two terminals. A dual run capacitor powers two motors from one can and has three terminals labeled HERM, FAN, and C.
Is a start capacitor the same as a run capacitor?
No. A start capacitor shows a range, like 88 to 108 µF, and is used in hard start kits. It is not a run capacitor.
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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.