Display shows E5 and compressor does not start or cycles rapidly; temperature cannot be maintained.

Important safety: Unplug the cooler before accessing the compressor compartment. Do not attempt sealed-system repairs without proper training.

• Check ventilation: Ensure the cooler has adequate clearance at the back and sides (typically at least 2–3 inches). Clean any dust from the rear grille and surrounding area.
• Inspect condenser coils: Remove the lower rear panel to access the compressor and condenser. Use a soft brush or vacuum to remove dust from the condenser coils and fan blades.
• Feel compressor temperature: Carefully touch the compressor shell. It will be warm during operation, but if it is extremely hot to the touch, allow it to cool for 30–60 minutes with power disconnected.
• Check the PTC relay and overload: On the side of the compressor, remove the plastic cover to expose the start relay and overload protector. Inspect for burn marks, melted plastic, or rattling pieces inside the relay when gently shaken.
• Replace suspect components: If the PTC relay or overload shows signs of damage, replace them with the correct hOmeLabs compressor start relay and overload protector kit for your model.
• Reassemble and test: Reinstall the cover and rear panel, plug the unit in, and listen for the compressor to start smoothly. Monitor for recurrence of E5.

Call a professional if: The compressor hums then clicks off repeatedly even with new relay/overload, or if E5 persists. The compressor itself or sealed system may be failing.