Ruud U802VA050317MSA Error Code A047_F: Inducer Fan 5 Minute Lockout (Active)

What Does Code A047_F Mean?

Code A047_F on the Ruud U802VA indicates that the inducer fan has triggered repeated 5-minute lockouts and the condition persists. The 'A' prefix means this is an active, ongoing fault — the pressure switch is consistently failing to prove proper exhaust draft, preventing the furnace from igniting.

Each time the furnace tries to start a heating cycle, the inducer motor runs to create draft. The pressure switch must close within 60 seconds to confirm adequate draft. When it fails, the control enters a 5-minute soft lockout and retries. Code A047_F appears when this pattern keeps repeating, indicating a persistent problem rather than a temporary condition.

The most common cause is a blocked exhaust vent — ice, snow, bird nests, or debris can obstruct the vent termination outside your home. A failing inducer motor that cannot generate sufficient draft, a cracked or water-filled pressure switch hose, or a failed pressure switch itself can also cause this code. Since this is a persistent fault, the problem is unlikely to resolve on its own.

Common Causes

How to Fix It: Clear the Exhaust Vent Blockage

What You'll Need

• Flashlight
• Ladder (if vent terminates on roof or high wall)
• Gloves

Steps

1. Turn off electrical power at the breaker or power switch AND shut off the gas supply valve Locate the furnace circuit breaker and flip it to OFF, or use the power switch on or near the furnace. Turn the gas shutoff valve to the OFF position (perpendicular to the pipe). If you smell gas at any point, leave the area immediately and call your gas company.
2. Locate and inspect the exhaust vent outside your home Find where the furnace exhaust vent exits your home — typically a PVC pipe through a side wall. Check for ice buildup, snow, bird nests, leaves, insect nests, or any other debris blocking the opening. Also check the combustion air intake pipe if your system has a separate one.
3. Clear any blockage from the vent opening Carefully remove any ice, debris, or obstructions from the exhaust vent and intake air pipe. Do not push debris further into the pipe. If ice is the problem, pour warm (not boiling) water to melt it, or carefully break it away.
4. Check for vent pipe damage or disconnection Visually inspect any accessible sections of the vent piping inside your home. Look for disconnected joints, sagging sections, or visible damage. Do not disassemble the vent system — just note any visible problems for a technician.
5. Restore gas and power, then test Turn the gas supply valve to ON and restore electrical power. Cycle the power (off for 30 seconds, then back on) to clear the lockout. Set the thermostat to call for heat and listen for the normal startup sequence: inducer motor starts, pressure switch clicks closed, then ignition.

When to Call a Professional

Contact a licensed HVAC technician if:

• The exhaust vent is clear but the furnace still locks out with this code
• The inducer motor sounds weak, rattles, or does not start at all
• You notice water dripping from the pressure switch hose or inducer housing
• The vent piping appears disconnected or damaged
• Code A047_F keeps recurring even after clearing vent blockages

✓ Verified against manufacturer service manual — March 2026