SOLID YELLOW
Lennox · ML14XC1 Merit Series 14 SEER Single-Stage Air Conditioner
Outdoor unit control board detecting low incoming voltage (below minimum operating voltage, typically 197 VAC for 208/230V units). Causes: utility voltage sag, undersized wire gauge, loose connections, failing contactor contacts. Measure voltage at unit disconnect — should be 208–253 VAC.
Error SOLID YELLOW on the Lennox ML14XC1 Merit Series 14 SEER Single-Stage Air Conditioner means: Low Voltage Warning. The top-ranked community fix is “Diagnose and Repair Low Voltage Issues Including Wire Gauge and Contactor” (medium difficulty, ~90 min, DIY cost: $10-$20). 2 community-ranked fixes available below.
Published February 2026 · 2 fixes · air conditioner
Content is based on manufacturer service documentation, community repair experience, and OEM technical bulletins. Always verify with your owner's manual.Learn about our editorial standards.
While many air conditioner repairs can be done safely at home, consider hiring a qualified technician if:
Average professional repair cost for this issue: $250-$450.
air_handler · 2 fixes
air_conditioner · 2 fixes
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heat_pump · 2 fixes
heat_pump · 2 fixes
High Pressure Switch Open
Low Pressure Switch Open
Compressor Thermal Overload
Short-Cycle Protection
Capacitor Failure (Run/Start)
Compressor Failure
Condenser Fan Motor Failure
Contactor Failure
The Lennox ML14XC1 Merit Series 14 SEER Single-Stage Air Conditioner has 8 other known error codes:
Error code SOLID YELLOW also appears on 5 other Lennox models:
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