I arrived for a warranty install no heat call. I inspected the system and found the trap on the system to have not been insulated when installed. I installed the insulation on the p-trap on the furnace and melted all ice in that section. Once the ice was melted the system came on and cycled on on its own and ran with no other issues at this time. The last 10’ of drain line is in the wall of the water heater closet. If this line freezes we I’ll have to run new drain line and insulate and run heat tape. This will be a chargeable task because this line was only accessible when the house was being built.