System wasn’t heating due to it being low on refrigerant. Leak detected on all 3 heads & middle head down stairs had a significant leak. (99+ppm) South head was picking up (6ppm). North head was picking up (11ppm). Those two heads weren’t near as significant as the middle downstairs head. Charged system up with 2lbs of 410a & system began heating properly again. Once system was charged, went ahead & isolated middle head by closing valves on condenser. Filters were cleaned on all heads & condenser was washed off. Left health sheet reports inside mail box. Other than that no other issues to report.