The answer to 'water heater short cycling' is that it occurs when the water heater turns on and off frequently, often before the tank is fully heated. This can be caused by a variety of issues, including a faulty thermostat, sediment buildup, or a problem with the heating element. Short cycling can waste energy, reduce the lifespan of the water heater, and lead to inconsistent hot water supply.
Some common symptoms of short cycling include the water heater turning on and off multiple times per hour, the water not getting as hot as it should, and higher than normal energy bills. To address the issue, you may need to clean the tank, replace the thermostat, or repair or replace the heating element. If the problem persists or you're not comfortable troubleshooting it yourself, it's best to call a professional HVAC technician to diagnose and fix the issue.