Furnace will not start, inducer fan may not run, F3 displayed on Ideal control

Safety: Turn off power to the furnace. Do not operate the furnace with the flue or intake disconnected except for brief testing by a qualified person.

Steps:

• Check flue and intake: From outside, inspect the Ideal furnace flue terminal and air intake for leaves, nests, ice, or debris. Clear any obstruction.
• Inspect pressure tubing: Remove the front panel and locate the pressure switch and its silicone tubes. Ensure tubes are not kinked, split, or full of water/condensate. Replace damaged tubing.
• Check inducer operation: With the panel back on, restore power and call for heat. Listen for the inducer fan starting. If it hums or does not run, the inducer motor or capacitor may be faulty.
• Test pressure switch (visual/basic): With power off, gently tap the pressure switch body and ensure the electrical connectors are tight. Do not bypass the switch for normal operation; this is a safety device.
• If F3 remains: A faulty pressure switch or inducer assembly is likely and should be tested with proper instruments and replaced by a qualified technician.