AC keeps running. Starts blowing strong, gets weaker. Water dripping in vent by furnace.

Your drain Is block or dirty filter make coil frozen clean drain change filter stop ac 24 hour leave fan on Furnace on after 24 hour check ac, if problem persist need too call hvac contractor

This symptom is a classic indicator of a frozen evaporator coil caused by restricted airflow or low refrigerant levels, paired with a blocked condensate drain line. ​Technical Breakdown & Diagnosis ​The Freezing Cycle (Blowing Strong to Weak): When your AC starts, it blows strong, cool air. However, if airflow is restricted (e.g., due to a heavily clogged air filter) or refrigerant is low, the evaporator coil drops below freezing. Moisture in the air condenses and freezes on the coil, building into a solid block of ice over several hours. This ice chokes off airflow through the ductwork, causing the weak airflow you noticed. ​Water Dripping and Pooling: As the continuous run time or shifting temperatures cause layers of accumulated ice to melt rapidly faster than the drain pan can handle—or if the condensate drain line itself is plugged with algae/debris—water overflows the drain pan and leaks out of the vent by the furnace onto the floor. ​Recommended Action Steps ​Shut Down the AC Immediately: Turn off the cooling system at the thermostat (switch to FAN ON or OFF) to let the ice melt completely. Continuing to run a frozen system can permanently damage the compressor. ​Check the Air Filter: Inspect and replace your HVAC filter immediately if it is dirty or clogged. ​Clear the Condensate Line: Ensure your condensate drain trap and line are clear of clogs to allow proper drainage. ​If the issue persists after thawing and replacing the filter, a licensed HVAC technician should check your refrigerant pressures and system airflow to prevent component failure.

Good morning, It sounds like you may have an issue with a dirty filter with your furnace/air handler. We would recommend having a maintenance performed on your equipment to ensure you have not just proper air flow but also that the equipment is working the way it should.

Sounds Like a air flow problem, check your filter, what happens if the airflow is restricted it will start freezing the coil, when that happens it will restrict the air flow, and continue to get worse.

First step: Check for airflow restriction - Furnace filter clean? Return air unobstructed? Next Step: Outdoor condensor coil clean and unobstructed? When was last Maintenance Inspection by qualified Refrigeration Technician? Book Service call with licensed Refrigeration Technician to check operation of system.

The symptoms suggest that the evaporator coil may be freezing due to restricted airflow, a dirty filter or coil, low refrigerant, or a blower issue. The water may be coming from the ice melting or from a blocked condensate drain. Turn the cooling system off to prevent further water damage or possible compressor damage. If it is safe to do so, set the thermostat fan to “ON” to help thaw the coil, and check or replace the air filter. If water is close to any electrical components, shut the system off completely. Even if the airflow returns after thawing, the underlying cause should be inspected by a licensed HVAC/refrigeration technician. The technician should check the evaporator coil, airflow, blower operation, condensate drain and refrigerant charge before restarting normal operation.