My mother had a new condencing lennox high efficiency gas furnace installed last summer. The furnace has venting problems. During cold weather the direct vent system ices up to the point that the furnace cannot operate properly and makes strange banging sounds when the burner is trying to fire. It happened 3 times. The exterior vent is exposed in a windy location between two homes.
I am wondering if building a wind break beside the vent, like a small fence jutting out from the wall might offer some protection from the wind to prevent the ice buildup inside the vent? Or is it some other kind of furnace problem? The installers were at the house 3 times to address the problem but it persists.