The alphabet soup on an HVAC data plate isn't decoration — each rating is a number a technician compares against a measurement to judge whether a component is healthy. Here's the full glossary.
| Rating | Means | How it's used |
|---|---|---|
| RLA | Rated Load Amps — the compressor's expected running draw | Measured amps well above RLA = a compressor working too hard (dirty coil, failing bearings, wrong charge) |
| LRA | Locked Rotor Amps — the inrush at start | A compressor pulling LRA repeatedly without starting = stuck rotor or a dead run capacitor |
| FLA | Full Load Amps — fan/blower motor rating | Same logic as RLA, for the motors |
| MCA | Minimum Circuit Ampacity | Sizes the wire feeding the unit — electricians and inspectors live by this number |
| Max Fuse / HACR | Largest allowed breaker or fuse | Protects the circuit; a bigger breaker is a code violation, not a fix |
| Capacitor spec | e.g. 45/5 MFD 440V | The exact replacement rating for the most-replaced part in AC — order by these numbers |
Why homeowners should care
You don't need to measure anything — but when a tech says "your compressor is pulling 22 amps against a 16.7 RLA," you now know that's a real diagnosis, not jargon. And when you order a capacitor yourself, the spec on the plate is the whole answer.
Get every rating without squinting
Our free Nameplate Decoder reads a photo of the plate and returns all of it — RLA, LRA, FLA, MCA, max fuse, capacitor spec, plus the model, age, tonnage and refrigerant — in one structured card, with a one-tap search for every matching part.
📷 Snap Your Nameplate — Decode It Free →
AI reads it in seconds. No login, no email.