American Standard mini split error code F5
PFC protection.
- TypeProtection
- SystemPower supply
- Can I fix it?Technician job
- Applies to4TXK / 4MXW / 4TYK series
What F5 means on a American Standard
The power-factor-correction stage reported a fault.
On this platform, F5 is a protection: the system stopped or throttled itself to prevent damage; many clear on their own once conditions return to normal.
Common causes
- Unstable supply voltage or a surge.
- A failed PFC circuit.
How to fix it yourself
Do the reset and the visual checks, but the underlying repair needs a technician with a meter and the service manual.
- Reset the system: switch the breaker (or the outdoor disconnect) off, wait a full five minutes so the boards fully discharge, then switch it back on and restart from the remote.
- If you own a multimeter and are comfortable using it, measure the supply voltage at the outdoor unit's L1 and L2 terminals with the unit running. A 230 V system should read roughly 208 to 253 VAC.
Switch off power at the breaker before opening either unit. Capacitors in the outdoor unit hold a charge for several minutes after power is cut.
When to call a technician
Usually an outdoor board replacement.
Which American Standard units show F5
This page applies to American Standard 4TXK / 4MXW / 4TYK hi-wall inverter and Mitsubishi Electric-built units units on the 4TXK / 4MXW / 4TYK series. American Standard's own documentation lists F5 as "PFC protection", the same definition used across the TCL platform it is built on. If your unit shows a code with a different shape (for example a four-character code, or a plain number), it is from a different table; use the lookup with your exact code.
Where American Standard shows this code
4TXK / 4MXW / 4TYK series: The indoor display shows the code in place of the set temperature. E codes are faults: something has failed and needs diagnosis. P, H, d and F codes are protections: the system stopped or throttled itself to prevent damage, and many clear on their own once conditions return to normal.
Other American Standard codes
Same part of the system as F5:
F5 on other brands
The same characters do not always mean the same thing. Check the brand on your unit.
- Pioneer F5 Outdoor fan speed out of control (outdoor fan motor fault) / Zone E indoor coil outlet sensor (T2B) fault, shown on the outdoor display
- Blueridge F5 Compressor discharge temperature sensor fault (open or short circuit) / Outdoor fan speed out of control (outdoor fan motor fault)
- Gree F5 Compressor discharge temperature sensor fault (open or short circuit)
- Zone Air F5 PFC protection
- Carrier F5 Outdoor fan speed out of control (outdoor fan motor fault)
- Heil F5 Outdoor fan speed out of control (outdoor fan motor fault) / Compressor discharge temperature sensor fault (open or short circuit)
- ACiQ F5 Outdoor fan speed out of control (outdoor fan motor fault) / PFC protection
Questions people ask
Can I reset a American Standard F5 code myself?
Yes. Turn the system off at the breaker for five minutes, then restart it. If F5 comes back, the fault is real and needs the checks above.
Is it safe to keep running a American Standard showing F5?
Not repeatedly. A protection code means the unit stopped itself to prevent damage, and resetting it over and over can turn a cheap repair into a compressor failure. Reset once, check the basics, and stop if it returns.
What will a technician check for F5?
Usually an outdoor board replacement. Ask for the measurements, not just a parts quote.
Sources
- Trane / American Standard Mini Split HW Inverter Service Manual (4TXK / 4MXW), SVM027A-EN, 2024
- Mitsubishi Electric M-Series service manuals (self-diagnosis tables)
Updated September 2026. Codes and definitions vary by model year. If your manual disagrees with this page, your manual wins. Send a correction.