LED flashes code 31; inducer may run but furnace will not ignite, or shuts down shortly after starting.

Safety: Turn off power and gas before disassembling venting or inducer components.

• Step 1 – Inspect vent and intake: Go outside and check the PVC intake and exhaust terminations for ice, snow, leaves, or nests. Clear any obstructions. Ensure vent terminations meet Tempstar installation clearances.
• Step 2 – Check condensate system (condensing models): Locate the condensate trap and drain lines. Remove and clean the trap, flushing out debris. Ensure the drain line slopes properly and is not kinked or frozen.
• Step 3 – Examine inducer motor: With power off, spin the inducer wheel by hand; it should turn freely. Listen for grinding or squealing during operation. Replace the Tempstar inducer assembly if noisy or slow.
• Step 4 – Test pressure switch: Use a manometer to verify that the inducer is producing the required negative pressure specified on the pressure switch label. If pressure is adequate but the switch does not close, replace the pressure switch.
• Step 5 – Inspect tubing and ports: Remove the pressure switch tubing and clean the port on the inducer or collector box with a small drill bit or wire (do not enlarge the hole). Reattach tubing securely.