5Troubleshooting DBW 2010 / 2016
502
Malfunction in water system
Heater shuts off, as heat exchangers (heater and vehicle) do
not give off sufficient heat.
Flow rate insufficient, as
• air or gas in heater, in heat exchangers or in system
sections.
• valves (flow controller) throttled, soiled or closed.
• impurities in system, e.g. filter or with bottlenecks.
• delivery capacity of circulation pump insufficient (air or
gas in pump casing), rotating direction incorrect – check
polarity.
• insufficient frost protection.
• system resistance too high (especially high at low
temperatures).
• circulation pump defective.
Vehicle's heat exchangers (water/air) give off insufficient
heat, as
• air or gas in heat exchangers or in system sections.
• soiled heat exchanger surfaces /(inside/outside).
• insufficient air inlet or air outlet.
• fan: delivery capacity insufficient/rotating direction
incorrect/resistance too high.
• percentage of antifreeze too high.
• heat exchanger too small.
Approximate determination of flow rate
Malfunction in fuel supply
No fuel delivered to heater. • Fuel tank empty.
• Kinked, sealed-off, clogged or leaky lines.
• Paraffin precipitation or frozen water inclusions in fuel
filter and/or lines.
• Ventilation opening in tank closed.
• Fuel line interchanged.
• Fuel filter soiled.
Malfunction in combustion
CO
2
value cannot be set to nominal value.
Combustion irregular.
• Air bubbles in intake line (intake line leaky).
• Fuel filter soiled or leaky.
• Fuel connection leaky (suction height, vacuum in tank);
see installation instructions.
• Fuel pump defective (pump pressure).
• Return line constricted.
• Screen in pump soiled.
• Atomiser nozzle defective.
• Combustion-air and exhaust lines constricted or closed
off.
• Motor speed of combustion motor insufficient.
Error symptom Possible cause
Fig. 501 General error symptoms (Section 2 of 2)