I arrived for a no heat call on a system we recently installed. I inspected the system and found that we ran heat tape and insulated the drain line but we did not insulate or put heat tape on the furnace p-trap. I wrapped the p-trap in heat tape and left it ready to be plugged in. The plug was burnt and I did not want to damage the heat tape. The homeowner is aware of the issue and will plug the heat tape in when it is needed.