Furnace displays E08 and will not complete ignition; inducer may start and stop.

Safety: Turn off power and gas. Do not blow into pressure switch ports with your mouth; use dry air only.

• Vent inspection: Check both intake and exhaust terminations for obstructions such as ice, snow, or debris. Clear any blockage and ensure proper clearances per Wolf installation instructions.
• Pressure tubing: Remove the rubber tubing from the pressure switch and inducer housing. Inspect for water, cracks, or kinks. Replace if brittle or damaged. Use a small piece of wire or drill bit (by hand) to gently clear the port on the inducer housing if clogged.
• Condensate drains (if applicable): On condensing Wolf furnaces, ensure the condensate trap and drain lines are not blocked. A backed-up trap can affect pressure readings.
• Switch test: A technician can test the pressure switch with a manometer and continuity meter. If the switch does not close at the specified negative pressure, replace it with the correct Wolf pressure switch model.