A heat pump water heater condensate alarm calls for checking its moisture-drain system, not assuming the storage tank has failed. Note the exact code and look for accessible drain restrictions or pump trouble. Heating behavior varies by model; some switch to electric elements. Do not bypass a drain sensor or open electrical compartments.
What does the alarm actually mean?
Use the code chart for the exact model. The cited Rheem manual identifies A108 as a blocked-condensate alarm and says the heating source defaults to electric elements. That is a useful example of why an alarm does not always mean all hot-water production stops. Another model can respond differently, so do not assume that the heater is safe to ignore because the showers remain warm.
Record the code, selected mode and any change in hot-water recovery. If a separate leak sensor also reports water, treat that as another finding to investigate. A leak alert with a dry floor explains why the sensor location matters.
Check the visible drainage path
Look only at accessible piping and the condensate pump, if installed. Note a crushed hose, a pipe that has shifted, a visible sag holding water, or a pump reservoir that is not emptying. Do not unplug equipment from a wet position or open the heater's upper enclosure to reach a sensor.
The cited Rheem model requires its drain line to slope away from the heater and prohibits condensate draining into the water heater's drain pan. Its manual also provides specific connection sizes and pump requirements. Those details belong to that installation, not a universal instruction to reconnect any heater to the nearest drain. The disposal point and connection must satisfy the actual manual and local requirements.
Clear the cause before resetting the message
A reset can remove a notification while leaving restricted drainage in place. Follow the owner's permitted cleaning instructions; internal pan access, sensor diagnosis and electrical testing belong to qualified service personnel. Do not add an improvised chemical mixture or use compressed air against an assembled heater connection.
Once repaired, the drainage should be checked during heat pump operation, not judged only while the heater is idle. The guide to hybrid water heaters covers why airflow and drainage are both needed. For water in the separate tray below a tank, see water heater drain pan overflow.