This is about documentation, not reliability. A brand with a short code list is not more likely to fail. It is harder to diagnose when it does.
What the catalog looks like
Codes we have sourced from homeowner-facing documentation, against how many systems we publish for that brand:
| brand | codes | systems |
|---|---|---|
| Daikin | 61 | 29 |
| Panasonic | 56 | 18 |
| Klimaire | 51 | 21 |
| MRCOOL | 50 | 12 |
| Mitsubishi Electric | 73 | 127 |
| LG | 51 | 50 |
| Della | 60 | 71 |
| GREE | 57 | 91 |
| Blueridge | 7 | 58 |
| Cooper & Hunter | 6 | 111 |
The top of that table is a brand publishing a full diagnostic table for a modest range. The bottom is the opposite.
Cooper & Hunter is the one to understand
6 published codes across 111 systems. That is our second-largest catalog by system count and one of our thinnest by documentation.
To be fair to the equipment: that number reflects what C&H puts in homeowner-facing literature, not how often the systems fail or how many faults they can report. The units almost certainly display more codes than that. What is missing is the public table telling you what they mean.
The practical consequence is that when a C&H system shows something outside that published set, you are dependent on your installer having the service manual. If you bought the equipment online and are looking for someone to diagnose it, that is a harder phone call. Blueridge is in a similar position - see the table above.
A short list is not always a bad sign
Bosch publishes a short list against a small range, and that is not thin documentation - Climate 5000 is essentially one product line, so there is less to document. Cosmo is similar and is built inside the GREE family, so GREE's much larger set usually applies to the equivalent system.
Read the ratio with the product range in mind. A brand with one line and a complete table is better documented than a brand with fifteen lines and a long list that covers only some of them.
Two brands publish nothing, and we say so
Goodman and Perfect Aire have no published homeowner-facing code table that we could find. We looked, we did not find one, and rather than import plausible codes from a related manufacturer we left those hubs empty and recorded why.
That is a deliberate choice worth explaining, because the alternative is common and worse. Fault codes are safety-adjacent - several point to refrigerant, sealed-system and electrical work - and publishing a guess about what a code means on a system you cannot verify is how someone opens a cabinet they should not have opened.
What to do with this
- Before buying, look up the brand's error-code hub. If it is thin, you are accepting that diagnosis will usually need a professional.
- After buying, get the service manual from your installer or retailer while you still have their attention. It is much harder to obtain later.
- When a code appears, start at the hub for your brand rather than a generic code lookup. Codes are not portable between manufacturers, and reading across from another brand is how people replace the wrong part.
- If your code is not listed, that is a real answer, not a failure of the page. Ask your installer for the service manual rather than guessing.
One honest limit on all of this: our counts are what we could source from manufacturer documentation. Where a brand publishes a table we have not found, our number understates them - and if you know of one, tell us through corrections and we will add it.