E8 code, inducer runs but pressure switch does not prove, furnace shuts down

Safety first: Turn off power and gas before working on venting or pressure switch components.

• Step 1 – Inspect vent pipes: For PVC vented Ducane models, check both intake and exhaust terminations outside for snow, ice, leaves, or nests. Clear any obstructions. For metal flues, ensure the vent cap is clear.
• Step 2 – Check condensate drain (condensing models): A clogged condensate trap or drain line can flood the inducer housing and prevent proper draft. Clean the trap and flush the drain line.
• Step 3 – Examine tubing: Remove the rubber tubing from the pressure switch and inducer port. Blow through it to ensure it is clear. Replace if brittle or cracked. Clean the inducer port with a small drill bit or wire (do not enlarge the hole).
• Step 4 – Reset and test: Reconnect tubing, restore power, and call for heat. If E8 persists, the pressure switch or inducer performance must be tested with a manometer by a technician.