Armstrong Air mini split code dF

What to do

You can almost always clear this yourself with the steps below.

1. Wait. Heating resumes on its own.
2. If dF shows for more than about 15 minutes at a time, or cycles constantly, the outdoor coil may be blocked or the defrost sensor (T3) faulty.

When to call a technician

This is not a fault. No technician is needed unless it will not clear.

Which Armstrong Air units show dF

This page applies to Armstrong Air 4DHV outdoor with DWH wall-mount indoor (2016 and later) units. Armstrong Air's own documentation lists dF as "Defrost cycle running", the same definition used across the Midea platform (classic codes) 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 Armstrong Air shows this code

The code appears on the indoor unit's LED display in place of the set temperature. Some models also blink the indicator lamps in a pattern that matches the code. E codes are faults in the indoor unit or its communication link, F codes are faults on the outdoor side, and P codes are protections: the outdoor unit has stopped itself to prevent damage. EC is the refrigerant leak check.

Other Armstrong Air codes

Same part of the system as dF:

All Armstrong Air error codes

dF on other brands

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

• Pioneer dF Defrost cycle running