Arrived to system off, turned system on and found rollout switch has failed. Bypassed rollout switch and tested system in A/C, A/C system is operating properly refrigerant pressures and temperatures are appropriate for indoor and outdoor weather conditions. Found furnace high limit has been bypassed, furnace no longer has any heat safeties if furnace where to overheat or rollout (flames starting to come out of burners) nothing would shut the system off. Found duct leakage on both supply and return. System is currently not operational, power is off at switch in attic. Spoke with homeowner and offered comfort advisor to give quote on updating furnace. She said she needed to talk to her fiancé. Furnace is 2010 and A/C is 2019.