Webasto 3500 problems

[carlager]

When I turn on my Webasto 3500 it sends out a lot of white smoke. After 2 attempts the green LED on the control button starts flashing error code

First thing to check is the fuel filter. I can see there is either water or air trapped in the filter (see attached photo).

I would like to clean the filter.

The instruction manual says that I should carefully bleed the system after the filter has bern cleaned.

My question is

How do I bleed the fuel syatem ?

Do I need a special tool for this ? If yes how do I operate it ? Or do I use the metering pump ? And if yes how do I bleed the system with the metering pump

Hope someone will help on this

[witzgall]

Here is what we have been told about these units:

The electronics are very sensitive to fuel/air leaks. If you have any leak in the lines, however slight, it can cause the problem you are experiencing. The photo you posted seems to support this position.

We have had a similar issue (cut-out with error, but no white smoek), but I have not gotten around to fixing it yet. I plan on checking both ends of the fuel line and perhaps sealing the threads on each fitting as well. I just ahve to find out what sealant can be used with diesel.

Chris

[David2452]

Bleeding the system is quite easy, assuming you have not got a huge length of fuel pipe and the correct bore and dip tube fitted, just try to start the unit four of five times and it will pull the fuel through. As a Webasto dealer I have the tool that pulses the pump to bleed the fuel through but rarely have to use it as a few start attempts usually gets the fuel up to the heater, you can see it moving along through the Tygon tube. All that said, your symptoms of white smoke may or not be due to a fuel issue and other condiotions can and do cause it, the white smoke is simply unburned fuel so for instance if the glowpin is covered in coke and is simply boiling the fuel rather than igniting it you would be presented with the same symptoms.

[s/v Thea]

I has an Espar that use to do that. In my case it was a result of low voltage at the unit so glow plug would not get hot enough for fuel to ignite. Check the voltage at the glow plug when unit is starting, could be a bad connection somewhere.

[goboatingnow]

It's almost certainly fuel blockage or low voltage. With air leaks you typically get misfiring then failure.


Dave

[David2452]

Not low voltage, that would give a fault code flash on the control knob and in any case the AT3500 will start down to 11.8v if the contacts are all clean, fuel blockage unlikely as that would result in no smoke and no start. My money is on a good bleed needed, or a new burned cartrige and glowpin or at least a good clean of them.

[jetsam]

Originally Posted by David2452

Bleeding the system is quite easy, assuming you have not got a huge length of fuel pipe and the correct bore and dip tube fitted, just try to start the unit four of five times and it will pull the fuel through. As a Webasto dealer I have the tool that pulses the pump to bleed the fuel through but rarely have to use it as a few start attempts usually gets the fuel up to the heater, you can see it moving along through the Tygon tube. All that said, your symptoms of white smoke may or not be due to a fuel issue and other condiotions can and do cause it, the white smoke is simply unburned fuel so for instance if the glowpin is covered in coke and is simply boiling the fuel rather than igniting it you would be presented with the same symptoms.

My webasto has run without problems since I bought the boat. The water separator on the fuel line broke recently. I fitted a new one today but despite about three attempts it is not working. At the first attempt I saw a small puff of smoke at the exhaust. It is blowing air ok but eventually shuts down. No faults are diplayed. I suspect fuel starvation but nothing is certain as I cannot say for certain if it was ok before the separator cracked. Do I need to bleed the system or should it bleed automatically ?

[David2452]

Originally Posted by jetsam

My webasto has run without problems since I bought the boat. The water separator on the fuel line broke recently. I fitted a new one today but despite about three attempts it is not working. At the first attempt I saw a small puff of smoke at the exhaust. It is blowing air ok but eventually shuts down. No faults are diplayed. I suspect fuel starvation but nothing is certain as I cannot say for certain if it was ok before the separator cracked. Do I need to bleed the system or should it bleed automatically ?

It is rather odd that it shows no faults, one would expct F 01 no start (after 2 start attempts) / no flame-up or F 02 flame-out (repeated > 5) if it didn't spark up. Usually all that is needed is a few start attempts to pump the fuel through. You can verify by removing the fuel hose at the heater and simply observing if fuel is spurting out. Check all new and old connections for air and fuel tightness. Is the fuel pump "ticking"?

[jetsam]

Thanks for the info. Didn't have much time today to look at the webasto. ran it a few times, blows air,no combustion and shuts off. Opened the fuel line just before the pump. No fuel. Does the fuel need gravity flow to reach pump. If so might explain problem as fuel tank is lower than ever before. Otherwise will open fuel line between pump and heater tomorrow. Still no faults displayed

[David2452]

Originally Posted by jetsam

Thanks for the info. Didn't have much time today to look at the webasto. ran it a few times, blows air,no combustion and shuts off. Opened the fuel line just before the pump. No fuel. Does the fuel need gravity flow to reach pump. If so might explain problem as fuel tank is lower than ever before. Otherwise will open fuel line between pump and heater tomorrow. Still no faults displayed

Rather disconcerting that it still shows no fault code, sometimes indicative of an expensive ECU failure but by no means a certainty. One point I now have to consider in light of your comment on low fuel. A properly installed Webasto fuel extraction standpipe will be terminated well short of the tank bottom, this is to prevent it picking up crud and also that extensive heater use will not compromise your fuel supply for engine use. The fact that no fuel is present downstream of the pump does not really mean anything and the pump does not require a head of fuel, I suggest that you pop a piece of clear tube over the supply downstream of the pump and give it a suck to see if you can draw fuel, this will at least tell you if the fuel is above the bottom of the standpipe and we can go from there with diagnostic help. Can you also tell me if the pump ticks during the start attempt. One further point which I hesitate to mention because it may appear patronising I apologise for asking this but it is worth getting out of the way now, you don't have it switched to "ventilate" do you as this would run the fan only and show no fault, though it would continue to run and not shut down automatically.

[jetsam]

UH OH. How do I know if it is switched to ventilate

[David2452]

Originally Posted by jetsam

UH OH. How do I know if it is switched to ventilate

There will be a switch on the control panel, if not then it is not cabled in so ignore the question.

[jetsam]

Originally Posted by David2452

There will be a switch on the control panel, if not then it is not cabled in so ignore the question.

i have a combi rimer which J have never mastered. I always hit the clock ymbol and the then the heater symbo;

[David2452]

Originally Posted by jetsam

i have a combi rimer which J have never mastered. I always hit the clock ymbol and the then the heater symbo;

With the 1531 combi timer just turn the dial fully clockwise and press the flame symbol to turn on or off no need to press the clock symbol.

[jetsam]

Just a quick one before I go back to the boat this afternoon.

When I press the flame symbol a flame symbol on the display appears for a second or so and then disapears. Should it stay on ?