50 years of mechanical repair experience.
jay kaye posted an answer for this A.O. Smith BTH-199 BTH-199 100 Gallon 199,000 BTU Cyclone Xi[REG] Commercial Gas Water Heater:
"Usually nothing to worry about. Sometimes sediment in the bottom of the tank will cause..."
jay kaye posted an answer for this A.O. Smith GPVH-50 Residential Water Heater, Natural Gas, 50 Gallon, ProMax Power Vent, 40,000 BTU:
"Maybe this error code chart for AO Smith Power vent will help you figure it out. Also link..."
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