Hello,
I have a Carrier 58SXB100 Deluxe gas fired electronic condensing furnace purchased 16 years ago. The furnace seems to work OK as far as heat output. However, with a recent cold snap of week-long temperatures of near zero, I can hear a gurgling sound from inside one of the large pvc pipes that runs from the outside to the furnace. Clearly, water is in the pipe and maybe some ice as well. One pipe is for intake of outside air. The other pipe is for furnace exhaust of burned fuel (hot air). Why is there water inside one of these PVC pipes? What can I do as a handy homeowner without deep pockets to correct this problem? Paul

It sounds normal. The furnace you have will create condensation all winter long. If the vent or drain line becomes restricted a pressure switch will keep the heat from working (safety switch).