Vacuum will not run; display shows E6 or six red flashes; unit may start briefly then shut down.

Safety first: Do not attempt to bypass the battery protection system. Use only the original or manufacturer-approved Tristar charger.

• Check charger output: Plug the charger into a known-good outlet. Confirm that the charger indicator light turns on. If you have a multimeter and are qualified, verify the output voltage matches the rating on the charger label.
• Charge fully: Place the battery on the charger or dock the vacuum as designed. Allow it to charge uninterrupted until the indicator shows full (often 3–5 hours). Do not use the vacuum while charging unless the manual explicitly allows it.
• Inspect battery age: If the battery is more than 2–3 years old or has been stored fully discharged for long periods, it may no longer accept a proper charge and should be replaced.
• Test with another charger or battery: If available, try a known-good Tristar charger or battery. If a different charger resolves the issue, replace the original charger. If a different battery works, replace the original battery pack.
• Persistent E6: If the error persists with known-good components, the main control PCB may be misreading battery voltage and should be replaced by a technician.