The answer to 'sump pump won't flush' is that a sump pump that won't flush or discharge water is likely experiencing a mechanical or electrical issue. Common causes include a clogged inlet screen, a faulty switch, a problem with the float, or a tripped circuit breaker. Symptoms may include the pump not turning on, running continuously, or not pumping any water.
To troubleshoot, first check the power supply and circuit breaker. Then inspect the inlet screen and clear any debris. Check the float mechanism to ensure it's moving freely. If the pump still doesn't work, you may need to replace the switch or the pump itself. For most sump pump issues, it's best to call a professional plumber who can properly diagnose and repair the problem.