American Standard mini split error code F1

Common causes

• A failed module or board.
• A surge event.

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.

1. 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.
2. 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

Board-level fault.

Which American Standard units show F1

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 F1 as "Power test module fault", 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 F1:

All American Standard error codes

F1 on other brands

The same characters do not always mean the same thing. Check the brand on your unit.

• Pioneer F1 Outdoor ambient temperature sensor (T4) open or short circuit / Zone A indoor coil outlet sensor (T2B) fault, shown on the outdoor display
• Blueridge F1 Indoor ambient (room) temperature sensor fault (open or short circuit) / Outdoor ambient temperature sensor (T4) open or short circuit
• Gree F1 Indoor ambient (room) temperature sensor fault (open or short circuit)
• Zone Air F1 Power test module fault
• Carrier F1 Outdoor ambient temperature sensor (T4) open or short circuit
• Heil F1 Outdoor ambient temperature sensor (T4) open or short circuit / Indoor ambient (room) temperature sensor fault (open or short circuit)
• ACiQ F1 Outdoor ambient temperature sensor (T4) open or short circuit / Power test module fault