13
Moderate
Carrier · Central Air Conditioners & Furnaces
Limit Circuit Lockout
Quick Answer
Error code 13 on your Carrier Central Air Conditioners & Furnaces means: Limit Circuit Lockout. This is usually fixable — see the step-by-step guide below.
Likely Causes
How to Fix It
1
Check and replace air filter if dirty
2
Verify all supply and return registers are open and unobstructed
3
Measure temperature rise across furnace and compare to nameplate rating
4
Check blower motor capacitor with a multimeter and replace if out of specification
5
Inspect blower wheel for dirt buildup and clean if necessary
Pro Tip
This fix requires some technical knowledge. If you're unsure about any step, consider contacting support or a qualified technician.
Parts You May Need
Air filter (size per unit specifications)
Blower motor capacitor
High-limit switch
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