Auxiliary Heating Mode
When switching on, the telltale in the control element (switch, clock timer...) illuminates. The heating unit water pump starts running and according to a specific sequence with pre-rinsing and pre-heating, the combustion air fan, heater element and fuel dosing pump set the combustion in motion. If a stable flame has formed, the heater element is switched off by a timer control.
Heating Mode
Depending on the heat required, the heating unit regulates in the stages "LARGE" and "SMALL". Here the temperature thresholds are definitively programmed into the electronic control unit. If the heat required in the "SMALL" stage is so low that the coolant temperature reaches 85 °C, the unit adjusts. Then there is a run-on of approx. 130 seconds, after which the heating unit switches off (control pause). The telltale is illuminated and the water pump continues to run.
In the Event of Malfunctions, the Following Points Must Be Checked First:
- If the heating unit does not start after switching on: switch heating unit off and on again but not more than twice in sequence.
If the Heating Unit Still Does Not Start, Then Check the Following Points and Verify Function:
- Enough fuel in the tank?
- Mechanical damage to components?
- When changing over to winter mode: Is there still summer diesel in the fuel line?
- Fuses OK?
- Electric wires, connections, terminals OK?
- Check combustion air ducts or exhaust gas ducts (blocked?).
Control and Safety Devices
If the heating unit does not ignite within 90 seconds after starting the fuel delivery, the start is repeated. If the heating unit does not ignite after another 90 seconds of fuel delivery, fault shutdown occurs. Locking occurs after an inadmissible number of unsuccessful start attempts 1)
If the flame goes out of its own accord during operation, a new start is performed first. If the heating unit does not ignite within 90 seconds after the fuel delivery has restarted or does ignite but goes out again within 15 minutes, a fault shutdown occurs.
By briefly switching off and on again, the fault shutdown can be cancelled. Do not repeat more than two times!
If the voltage drops below approx. 10 volt or increases above approx. 15 volt (lower / upper voltage limit), there is a time-delayed fault shutdown.
In the event of overheating, caused by lack of water or poorly ventilated cooling water circuit, the overheating sensor responds, the supply of fuel is interrupted and a fault shutdown occurs.
After the cause for overheating has been eliminated, the unit can be started again by switching off and on again (prerequisite: the unit has cooled down adequately, cooling water temperature <70 °C.
Locking takes place if the system has switched off an inadmissible number of times because of overheating 1) .
With a defective heater element and interrupted electrical conduction to the dosing pump, the HYDRONIC does not start.
The rotational speed of the fan motor is monitored continuously. If the fan motor does not start, if it locks up or the rotational speed drops below 40 % of the nominal speed, a fault shutdown occurs after 60 seconds.
1
) To cancel the lock and/or to read out faults, a diagnosis test must be performed with the diagnostic unit (Eberspaecher), as described in the Troubleshooting and Repair Instructions from Eberspaecher for HYDRONIC B 5 W S / D 5 W S.