80% chance that the batteries are dead.  19% chance they just don’t know the code (send them the online manual) 1% chance it’s bad. buy a new one for $20. 

About 15 years ago, I met a retired CPA who gave a person he casually met his entire life's savings of $125,000 because the person he met said he had invented batteries that work with only water.

Requires batteries and wifi with some control work to the heater. 

I'm assuming it's electric/battery operated.I suppose I'd remind them that I'd treat any damage from it just like any other damage. 

Drive an hour to see the smoke detector needed a 9 volt battery .

FREE super charging for anyone in the area and they can over the AIR release more battery capacity and give the cars greater range.. all with over the air software .. 

If you have no electric arlo will work by battery. 

(It works best if you have a powered doorbell because it will auto charge the battery).

Since I started managing rentals, some of the changes are, depending on the location, voucher holders (Section 8)/source of income became a protected class, smoke detectors have to have 10-year sealed batteries, and you have to take 2-step screening with the first step you can NOT screen/ask the criminal history.

Tesla battery manufacturing also hiring in Austin.