Diagnosis
That's usually a power supply issue, not a sign the whole heater is dying. Fluctuating voltage or a poor connection at the outlet can cause the digital display to flicker or show garbled segments.
How to Fix It
Unplug the heater from the wall outlet. Check the plug and the heater's power cord for any damage. Plug it directly into a different, known-good wall outlet—avoid using an extension cord or power strip, as these heaters draw a lot of current (up to 1500W). A poor connection in a strip can cause voltage drops that freak out the digital display.
If That Didn't Work
If the display is still malfunctioning when plugged directly into a solid wall outlet, the internal control board or the display connection itself has likely failed. This requires professional repair. Contact Pelonis support.
Heads Up
These are high-wattage appliances. Always plug them directly into a wall outlet. Using an undersized extension cord or a crowded power strip is a fire risk and can cause these exact display/power issues.