Main floor no heat. Found outdoor unit frozen. Upon inspection found faulty defrost board and sensor. Contactor starting to pit and blower and evap coil very dirty. System also lacks flood protection and has biological growth inside air handler. Tested heat kit, heat kit working properly and thawed system by removing fan and running in ac. Board and sensor are not available locally and need to be ordered. Lead time is 3-5 business days. Customer getting quote for replacement equipment tomorrow between 3-6. Quoted repairs.