In fairness to all, we don't discuss pricing on the Wall. Thanks for your cooperation.
American Standard condensing propane furnace lockout issues
We installed an American Standard warm air furnace in a customers home about five years ago. The system ran fine for years and then...this year has had nothing but lockout issues. The fault code comes up as a 2-flash which is (3 unsuccessful tries for ignition). We verified correct inlet gas pressure-12"WC, correct manifold pressure-6"WC first stage and 10"WC second stage. When fired, the pressure drop is not more than 1.25"WC. Flame signal is 2 micro amps. The primary heat exchanger was cleaned, the fresh air pipe disconnected, the pressure switch closes at he proper settings. The flame sensor was replaced along with the circuit board to try to eliminate grounding issues but still the same thing. The propane tank was filled in the summer and just recently filled again late February. Maybe I'm missing some thing obvious here but what else should I be checking?