515
Thermo plus 160/230/300/350 5 Troubleshooting
5.6.10 Fuel pump inspection
ATTENTION:
The pump pressure of the fuel pump is adjusted to a
defined value in the factory.
It is permitted to readjust the pump pressure.
According to the manufacturer's specifications the
fuel pump and fuel hoses must be replaced after 5
years.
NOTE:
If bio diesel or FAME is used, the fuel pump and fuel lines
must be replaced according to the latest technical infor-
mation / notification.
The ignition electrode must be removed during the
pump pressure check.
NOTE:
The fuel pump pressure can be checked while the burner
head is removed, using the Component Test menu of STT
diagnosis.
A pressure test gauge with a display range from 0 to 15
bar as well as a bleeding feature is required (Fig. 511).
The pressure test gauge can be obtained from a Valeo
Service Center or a distribution partner.
The following inspections should be performed prior
to testing the pump pressure:
• Is the CO
2
content properly adjusted?
• Is the fuel temperature 15...25°C?
• Are available check valves in the fuel supply and
return line opened?
• Was the fuel filter in the fuel supply line replaced?
• Are the filters (screens) in the pump inlet clean?
• Is the fuel delivered without bubbles?
•
Attach a transparent hose for testing.
Inspection using the STT diagnosis
• Remove burner head (see 8.2).
• Connect the test plug instead of the temperature
sensor plug to the control device.
• Remove ignition electrode (see 8.6).
• Remove fuel nozzle (see 8.11).
• Screw the pressure test gauge into the nozzle block
(20 Nm ±2).
NOTE:
Exert counter pressure at the hexagon of the fuel
pump nozzle block using a tool.
• Reconnect the heater with the vehicle electrical
system.
• Connect the STT diagnosis to the heater.
• Start STT diagnosis, establish connection to the
heater and open the Component Test menu.
• Select the fuel pump pressure test in the Component
Test menu.
• Check the information and follow the instructions
provided by STT diagnosis..
• The motor is started using the speed programmed in
the control device.
• Open the bleed port at the pressure test gauge until
some fuel escapes, collect it e.g. with a cloth.
Close the bleed port and read the present pressure at
the gauge.
• Compare the actual pressure with the target pressure
of 8 +1 bar.
If the specified pressure cannot be reached, it can be
readjusted. For that rotate the adjusting screw (see
Fig. 510) max. one revolution. If the prescribed pres-
sure despite readjustement not be achieved or occur
leaks, the fuel pump must be replaced.
• Follow the instructions provided by STT diagnosis.
• After the test is completed, exit the STT diagnosis as
needed.
• Disconnect the heater from the vehicle electrical
system (Observe 5.2 !).
• Remove the test plug.
• Remove the pressure test gauge.
NOTE:
Exert counter pressure at the hexagon of the fuel
pump nozzle block using a tool.
• Install fuel nozzle (see 8.11).
Risc of electric shock!
Warning!
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