American Standard Furnace Error Code 184 – Meaning, Causes & Fix

What Does 184 Mean?

What Causes This Error?

• Flame sensor rod coated with carbon or oxidation reducing ionization signal
• Hot surface ignitor cracked, weakened, or not reaching ignition temperature
• Low gas supply pressure — gas company supply issue or undersized gas line
• Gas shutoff valve partially closed at the furnace or upstream
• Gas valve solenoid not opening fully or at the correct time in the sequence
• Wrong fuel type — natural gas orifices on an LP system or vice versa
• Control board not delivering correct voltage to the ignitor or gas valve relay
• Flame sensor wiring loose, corroded, or disconnected

How to Fix 184

1. 1

   Clear the lockout and observe the next ignition attempt. On the AccuLink or ComfortLink II thermostat, navigate to Equipment Status > Diagnostics and clear the fault. Alternatively, switch the furnace off at the power switch for 30 seconds, then back on. Initiate a heat call and stand near the furnace. Watch and listen: the inducer should start, then approximately 30–45 seconds later the ignitor should glow and you should hear the gas valve click open followed by burner ignition. Observe how many attempts are made before lockout.

2. 2

   Verify gas supply. Check that the gas shutoff valve on the line entering the furnace is fully open (lever parallel to the pipe). Verify that other gas appliances in the home (water heater, range) are functioning normally — if they are also out, the issue is with the gas utility supply. On LP systems, check the tank level.

3. 3

   Clean the flame sensor rod. Turn the furnace fully off at the power switch. Locate the flame sensor — a metal rod mounted in the burner box, connected by a single wire. Remove the single mounting screw, slide the sensor out, and use 220-grit emery cloth or fine steel wool to lightly polish the metal rod until it is shiny. Do not touch the polished surface with bare fingers. Reinstall firmly. This single step resolves error 184 in the majority of American Standard furnace cases.

4. 4

   Inspect the hot surface ignitor. With the furnace off and cool, visually inspect the ignitor element for cracks. The ignitor is a fragile ceramic component near the burners — even a hairline crack renders it non-functional. Never touch the element surface with bare skin. If cracked, order the correct OEM replacement ignitor for your specific American Standard furnace model. Ignitor replacement is user-serviceable on most models with care.

5. 5

   Check the flame sensor wiring connection. Trace the single wire from the flame sensor back to its connector on the control board. Verify the connector is fully seated and shows no corrosion or heat damage. A loose flame sensor wire causes intermittent or complete loss of flame detection signal, triggering error 184 even when the burner is actually lit.

6. 6

   Check the AccuLink thermostat for additional stored codes. Navigate to Equipment Status > Active Faults or Fault History on the thermostat. Additional codes stored alongside 184 narrow the diagnosis — for example, a simultaneous pressure switch code would redirect focus to the inducer and drain rather than the flame sensor, while a gas valve code confirms a valve fault.

When to Call a Professional

Can You Still Use the Device?

Do not attempt to manually force the furnace to ignite or bypass the ignition lockout while error 184 is active. Repeated failed ignition attempts accumulate unburned gas in the heat exchanger, which is a fire and explosion hazard. Clear the fault, resolve the root cause, and verify proper ignition before relying on the furnace.