Replacing this part requires matching the capacitance and voltage ratings to your existing setup. This guide explains how to read your old label and choose a compatible 30/5 MFD capacitor.
Parts with these numbers
30+5 MFD 440/370V Round Dual Run Capacitor (Bluefin CPDRR1-305)
30+5 MFD 440/370V Round Dual Run Capacitor (Titan Pro TRCFD305)
30+5 MFD 440/370V Oval Dual Run Capacitor (Titan Pro TOCFD305)
- 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 30/5 MFD and Voltage Ratings Mean
The numbers on this capacitor tell you how much energy it stores and the electrical load it handles. Capacitance is measured in microfarads, which may be written as MFD, uF, or µF on the metal case.
A dual run capacitor serves two motors from a single metal can. The larger number, 30 MFD, powers your compressor. The smaller number, 5 MFD, powers the outdoor fan motor. These numbers must match your old part exactly.
The voltage rating is listed as 440/370V. A 440V rating can safely replace a 370V rating because capacitors can handle equal or higher voltage. Never use a lower voltage rating than what your system requires.
Reading the Terminals and Label on Your Old Part
A dual run capacitor has three sets of posts on top. These posts are marked HERM, FAN, and C. The HERM terminal connects to the compressor, the FAN terminal connects to the outdoor fan motor, and the C terminal is common.
Take a clear photo of all wiring connections before disconnecting anything. Move wires over one at a time to ensure they land on the correct terminals of the replacement part.
Comparing Available 30/5 Capacitors
All compatible 30/5 MFD capacitors share the same electrical ratings, but their physical shapes can differ. You should choose the shape that fits inside your outdoor unit's mounting bracket.
- Bluefin CPDRR1-305: Round dual run capacitor rated at 30 + 5 µF and 440/370V.
- Titan Pro TRCFD305: Round dual run capacitor rated at 30 + 5 µF and 440/370V. Replaces TRCD305, CD30-5X440R, and CAP-30/5/440R.
- Titan Pro TOCFD305: Oval dual run capacitor rated at 30 + 5 µF and 440/370V. Replaces CD30-5X370, CD30-5X440, and CAP-30/5/440.
Signs of a Failing Air Conditioner Capacitor
When a dual run capacitor gets weak or fails, your air conditioner cannot start its motors properly. A fan that hums but will not spin is often caused by a bad capacitor rather than a broken motor.
Physical damage is another clear sign of failure. If the top of the metal can is bulging, domed, or leaking fluid, the capacitor has failed and needs to be replaced.
How to confirm it fits
- Turn off the breaker and the outdoor disconnect, then confirm power is off with a tester.
- Check the capacitance label on your old unit to confirm it reads 30 + 5 µF, MFD, or uF.
- Verify the voltage rating on the old label is 370V or 440V.
- Check the shape of the existing metal can to see if your mounting bracket requires a round or oval part.
- Confirm your old part is a dual run type with three terminal posts labeled HERM, FAN, and C.
Questions
Can I replace a 370V capacitor with a 440V capacitor?
Yes. A 440V capacitor can safely replace a 370V capacitor. Voltage ratings can always be the same or higher, but never lower.
Does the shape of the capacitor affect how it works?
No. Round and oval capacitors with the same microfarad and voltage ratings perform the exact same job. Choose the shape that fits your unit's mounting bracket.
What do the three terminals on a dual run capacitor do?
The HERM terminal connects to the compressor, the FAN terminal connects to the outdoor fan motor, and the C terminal is common.
Can I use a start capacitor instead of a dual run capacitor?
No. A start capacitor lists a microfarad range, such as 88 to 108 µF, and is used only in hard start kits. It cannot replace a dual run 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.