Truma RV furnace fault codes
RV forced-air propane furnaces lock out after failed ignition attempts. Many use a status LED on the control board that flashes a fault pattern.
How to read the code
Find the control board (often behind an exterior access panel or inside under a vent) and watch the status LED. Count the flashes in each group; the pattern maps to a specific fault.
All documented codes
E2H / E16H warning
VarioHeat ignition/flame fault: the furnace released gas and attempted ignition but no fla… E43H warning
Over-voltage: the supply voltage to the heater is too high (Truma cites above roughly 16.4… E44H warning
Under-voltage: the supply voltage to the heater is too low (Truma cites below roughly 10.0… E112H / E212H danger
Gas/flame fault group: the burner did not ignite or the flame was not detected, and/or com… W18H warning
Warm-air outlet or circulated-air (return air) intake is blocked, so the unit cannot move … W25H–W29H warning
VarioHeat voltage and airflow warnings: W25H = overvoltage above ~16.4 V; W26H = undervolt…
VarioHeat ignition/flame fault: the furnace released gas and attempted ignition but no fla… E43H warning
Over-voltage: the supply voltage to the heater is too high (Truma cites above roughly 16.4… E44H warning
Under-voltage: the supply voltage to the heater is too low (Truma cites below roughly 10.0… E112H / E212H danger
Gas/flame fault group: the burner did not ignite or the flame was not detected, and/or com… W18H warning
Warm-air outlet or circulated-air (return air) intake is blocked, so the unit cannot move … W25H–W29H warning
VarioHeat voltage and airflow warnings: W25H = overvoltage above ~16.4 V; W26H = undervolt…
Which of these codes apply to your model?
Not every code below exists on every Truma furnace. Pick your model number to see only the table that applies to it — and which codes it will never show.