On the covered Noritz tankless water heater, 94, EC94, EC941, EC942 means the exhaust temperature is too high on a condensing unit. On smaller units with a display window it appears as EC941, a warning when exhaust exceeds 182 degrees Fahrenheit that limits input to 77,000 BTU or less, or EC942, a shutdown when exhaust exceeds 191 degrees Fahrenheit. First, check that the vent terminations are clear of debris.
Try in this order
0 of 2 completedWhat to do first
ReversibleCheck that the vent terminations are clear of debris.
Correct only the documented fault domain
ReversibleNoritz's common causes: scale in the heat exchanger, restrictions in the exhaust or intake venting, a dirty fan, and incorrect manifold gas pressures. A dark gray spot on the copper heat exchanger indicates scale.
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What does 94, EC94, EC941, EC942 mean on a Noritz tankless water heater?+
The exhaust temperature is too high on a condensing unit. On smaller units with a display window it appears as EC941, a warning when exhaust exceeds 182 degrees Fahrenheit that limits input to 77,000 BTU or less, or EC942, a shutdown when exhaust exceeds 191 degrees Fahrenheit.