34
Easy Fix
Carrier · Central Air Conditioners & Furnaces
Ignition Proving Failure
Quick Answer
Error code 34 on your Carrier Central Air Conditioners & Furnaces means: Ignition Proving Failure. This is usually fixable — see the step-by-step guide below.
Likely Causes
How to Fix It
1
Remove the flame sensor and clean it with fine emery cloth or steel wool
2
Measure flame current with a microamp meter (should be above 1.0 microamps, ideally 2-6 microamps)
3
Check that the furnace chassis is properly grounded
4
Verify gas pressure at the manifold with a manometer
5
Inspect the flame sensor wire and connector for corrosion
Pro Tip
This is a common issue that most users can resolve without specialized tools. Try the first step before moving on to more complex solutions.
Parts You May Need
Flame sensor
Emery cloth
Flame sensor gasket
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