Mike, We recently purchased a home that has A Ruud Acheiver 90 Plus furnace. The furnace is appr. 1 yr. old. We had an air conditioner replace last summer and the company that installed the air conditioner told me the furnace should have a 2" PVC line run to the outside to take in fresh air to the combustion chamber. Anyhow I ran a 2" PVC line to the outside as suggested, but now the furnace won't light. Any suggestions without calling a contractor. Thanks, Jerry