HVAC Capacitor Size by Tonnage (Dual Run Fallback Table)
The typical dual run capacitor value in MFD for a 1.5 to 5 ton residential outdoor unit, for the day the nameplate is missing or unreadable. No account, nothing to install.
EMERGENCY FALLBACK ONLY — NOT A SUBSTITUTE FOR THE NAMEPLATE
This is a general reference range, not a diagnosis or a guaranteed-correct value — the actual required capacitance depends on your specific motor's design, not just its tonnage. Always use the value printed on the motor's own nameplate when it's legible. Use this chart only as a fallback when the nameplate is missing or unreadable, and verify your own work. A wrong capacitor can damage the motor. You are responsible for doing your own research before acting on this.
Capacitor Sizing Fallback Table
| Tonnage | Typical MFD | Notes |
|---|---|---|
| 1.5 Ton | 30/5 MFD | Common fallback for 1.5-ton residential outdoor units. |
| 2.0 Ton | 35/5 MFD | Common fallback for 2-ton residential outdoor units. |
| 2.5 Ton | 35/5 - 40/5 MFD | Typical 2.5-ton dual run capacitor range. |
| 3.0 Ton | 40/5 MFD | Common fallback for 3-ton residential outdoor units. |
| 3.5 Ton | 45/5 MFD | Common fallback for 3.5-ton residential outdoor units. |
| 4.0 Ton | 50/5 MFD | Common fallback for 4-ton residential outdoor units. |
| 5.0 Ton | 60/5 MFD | Common fallback for 5-ton residential outdoor units. |
Frequently asked questions
What size capacitor does a 3 ton air conditioner use?
The Equipment Tracker app's fallback table lists 40/5 MFD as the common fallback for a 3-ton residential outdoor unit. It is a general reference range, not a guaranteed-correct value: the capacitance a motor needs depends on its own design, not just its tonnage. Use the value printed on the motor's own nameplate whenever it is legible.
What does 40/5 MFD mean?
MFD is microfarads (the same unit as uF). A dual run capacitor carries two values in one can, written like 40/5: the first number is the compressor's capacitance and the second is the fan motor's. Read the new capacitor's label against the old one.
Does the nameplate override this table?
Yes. The table is an emergency fallback only and not a substitute for the nameplate. Use it only when the nameplate is missing or unreadable, and verify your own work. A wrong capacitor can damage the motor.
Does the table list a voltage rating?
No. The Equipment Tracker app's table gives the capacitance (MFD) and a note for each tonnage and nothing else, so this page shows no voltage. Take the voltage rating from the capacitor you are replacing or from the equipment nameplate.
Why is 2.5 ton a range and the others a single value?
That is how the app's table reads: the 2.5 ton row is 35/5 - 40/5 MFD, described as the typical 2.5-ton dual run capacitor range. Every other row is one value.
Does this page store anything or need an account?
No to both. If you want the unit, its capacitor values and its service history kept on each piece of equipment, that is what Equipment Tracker is for.
Keep each unit's nameplate details and service history in Equipment Tracker
Write the unit, its capacitor and nameplate values and service history down once and they are there on the next service call, on your phone, with or without signal. The core of the app is free on the phone, and every first plan, Pro or Team, starts with a 7-day free trial.
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