🔧Boilers Error Codes
Gas and condensing boiler error codes. Lockout faults, ignition failures, pressure switch errors, and combustion safety codes for residential and commercial boilers including Burnham and Weil-McLain.
77 guides
Section editor: James Rutherford · Master Plumber
Recent Boilers Guides
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Burnham/U.S. Boiler Fault Code 2 — Ignition Lockout Fix
Fault Code 2 on a Burnham (now U.S. Boiler Company) 7-Series, 8-Series, ESC2, or Alpine gas-fired boiler indicates an ignition lockout — the integrated...
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Lochinvar Knight E02 — High Limit / Stack Temp Fix
E02 on a Lochinvar Knight wall-hung (WHN, WBN) or Knight XL floor-mount condensing boiler indicates a high limit or stack temperature lockout. The SMART...
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Navien NPE/NCB Code E003 — Ignition Failure Fix
E003 on a Navien NPE-A, NPE-S, NCB, or NFC series condensing combi/boiler indicates an ignition failure — the control attempted ignition through its full...
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Weil-McLain Code 1 — No Flame Sensed Fix
Code 1 on a Weil-McLain Gold or Ultra Series boiler means the boiler attempted ignition but did not prove flame within the trial-for-ignition window...
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Weil-McLain Code 3 — Low Water Cutoff Fix
Code 3 on a Weil-McLain Gold or Ultra Series boiler (Ultra 80/105/155/230/310/399, GV90+, and WM97+ platforms) indicates a low water cutoff (LWCO) lockout —...
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Burnham Series 2 Boiler Error Codes: Complete Guide
Updated:Burnham Series 2 boiler error codes and fault diagnostics. Fault codes, lockout causes, and technician-level troubleshooting for Series 2 cast iron boilers.
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Navien NFC Combi Boiler Error Codes: Complete Guide
Updated:Navien NFC combi boiler error codes and fault diagnostics. E-series error codes, causes, and technician-level troubleshooting procedures.
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Weil-McLain Ultra Series Boiler Error Codes: Complete Guide
Updated:Weil-McLain Ultra Series boiler error codes and fault diagnostics. E-series fault codes, causes, and technician-level troubleshooting procedures.
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Boiler vs. Furnace Replacement: Cost, Efficiency, and When to Switch
Boiler replacement costs $4,000–$8,000 vs. furnace $2,200–$5,500. Hydronic vs. forced air comparison, conversion costs, and efficiency pros and cons for Northeast and Midwest homes.
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Laars Boiler Fault Codes — Complete Fix Guide
Laars boiler fault codes for Laars Mighty Therm, Pennant, and NeoTherm series. What each code means and how to fix it.
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Vaillant Boiler Fault Codes — Complete Fix Guide
Vaillant boiler fault codes for ecoTEC, ecoFIT, and turboTEC series. What each code means and how to fix it.
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Lochinvar Knight Boiler Error Messages — Complete Display Guide
Lochinvar Knight boiler display messages explained: Flame Fail Ign, Air Pressure SW, Fan Speed, Flow Switch LWCO, Fatal Error. Step-by-step diagnosis and fix guide.
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