Applies To
Intermatic ET1100, ET1700, and ET8000 Series electronic timers with battery trays (all models).
Question / Problem
How do I troubleshoot battery backup issues or time loss on my ET1100, ET1700, or ET8000 timer?
Safety Warning
Warning: Always turn off power at the circuit breaker before servicing the timer. Use a voltage tester to confirm power is off. Follow local electrical codes and avoid contact with live parts.
Common Causes / Conditions
- Backup batteries are weak, expired, or not seated properly in the tray.
- The timer uses two field-replaceable AAA alkaline batteries.
- Batteries should typically be replaced every two to three years.
- Excessive heat, moisture, or corrosion inside the enclosure can affect battery performance.
Step-by-Step Resolution
Turn Off Power to the Timer
Switch off the breaker supplying the timer and verify the display is off before opening the enclosure.
Access the Battery Tray
Slide the battery tray downward to expose the two AAA batteries.
Remove and Inspect the Batteries
Take out both batteries and check for corrosion, leakage, damage, or swollen labels.
Inspect the Battery Tray Contacts
Check the metal contacts on both ends of the tray for discoloration, rust, or residue.
Clean Light Corrosion
If minor corrosion is present, clean the contacts using a dry cloth or a small dry brush. Do not use liquids or cleaning sprays.
Install New Batteries
Insert two fresh AAA alkaline batteries. Ensure the positive and negative ends match the markings in the tray.
Reinsert the Battery Tray
Slide the tray back into its fully seated position until secure.
Restore Power and Reset the Timer
Turn the breaker back on, then set the current time and reenter your programmed events.
Test the Memory Backup
Briefly turn the breaker off and back on again to verify that the timer retains the correct time and event schedule.
Evaluate Severe Corrosion or Damage
If contacts are heavily damaged or corroded, memory backup may no longer function. Replacement of the timer may be required.
Tips / Additional Notes
- Always replace both batteries at the same time using fresh alkaline batteries.
- Weak or expired batteries can cause time loss during brief power interruptions.
- If time loss persists after installing new batteries, internal damage may have occurred. Excessive corrosion on the battery tray can migrate into the timer and affect the memory circuit.
- Do not mix different battery types or use partially depleted batteries.