We had a York Affinity 9.C Series Modulating Furnace (80,000BTU) installed in March of 2008, and had no problems last winter. Today, we had no heat and the circut board had 5 red flashes repeating. We called our installer, who came out within a few hours, but suggested that the problem may have been becuase we closed our basement registers, a switch was overheating. We always close the basement registers in the winter so that more warm air reaches the 2 floors above, but we opened them all as he suggested.
It's 2AM and we have no heat again, and will have to have the installer out again in the morning. Any suggestions on what I can tell him to look for? I was never happy with the horizontal pitch of the 2 vent/intake pipes. I don't want to suggest a red herring, but could that be an issue?