Whirlpool Dryer Error Code F:28

The F:28 fault code on a Whirlpool dryer indicates an open circuit condition in the moisture sensor strip. The moisture sensor system typically consists of two metal sensor bars located inside the drum that detect the electrical conductivity of clothes tumbling against them. When clothes are wet, they conduct a small electrical current between the bars, signaling the control board to continue the drying cycle. When the sensor reads an open circuit, the control board is receiving no signal at all, which points to a break in the sensor circuit rather than simply dry laundry.

This fault code is important to note: it will ONLY appear during the dryer's diagnostic test mode, not during normal operation. This means a technician must actively enter the diagnostic sequence to observe this code. During normal cycles, a failed moisture sensor may cause the dryer to run on a timed basis or shut off prematurely, but F:28 itself surfaces only under test conditions. The diagnostic entry point for this code is TEST #5, which provides the specific resistance and continuity checks needed to isolate the fault.

Common root causes include physical damage to the sensor bars themselves, corrosion or buildup on the sensor strip contacts, a broken wire in the harness connecting the sensor to the control board, or a failed connection at the board or sensor terminals. Lint accumulation or fabric softener residue coating the sensor bars can also interfere with conductivity, though a heavy coating is more likely to cause erratic readings than a true open circuit reading.