Furnace kicking out on pressure switch Jumped out the pressure switch electrically, connected manometer to pressure ports on the collector box Pressure stayed at -1.6"wc the entire time the furnace ran (this rules out clogged drain, clogged intake and exhaust pipes, heat exchanger issue, and inducer motor issue) Switch rated at -0.90"wc Calibrated a universal pressure switch to close at -0.90"wc, it opens at -0.82"wc Used correct size restrictor orifices compared to factory pressure switch Installed into furnace Furnace operating normally at this time.