Diagnosed Lennox furnace with no heat issue showing code 228 (pressure switch calibration failure) and high-pressure switch failure. Verified proper exhaust venting, cleared drain, and checked concentric vent for debris. Confirmed good vacuum with manometer readings. Replaced pressure switches, restoring system operation. Observed moisture leaking from collector box and press seam leakage from inducer motor. Recommended replacement of collector box, inducer, and pressure switch for complete resolution.