eberspacher only working on vent mode

[trowell]

Good evening. Does anyone out there have any experience of a D2 wired up with a 701 series controller only operating in vent mode?

Mine was serviced by myself and ran very well up untill recently but now only blows cold. There is no attempt by the heater to start up normally and no ticking sound from the pump, just cold air. To add to this conundrum the display does not show the fan symbol which as far as I can discover from fault finding literature, should be displayed when running in this way. I'm worried that its the heaters computer that has failed but could it be that its just the controller thats stuffed? I have tried disconnecting both heater and controller from the supply in the hope that a 'hiccup' might clear itself to no avail....

any input very much appreciated

T

 

[rib]

have you checked the pump ?.had this problem once and trying hard to remember cure.fuel to pump or pump/glow plug

 

[rib]

can you hear the pump trying to work during start up phase

 

[Bloater]

I've seen something like this before when my fuel level was low and basically the heater was just sucking air. When this happens the clicking noise can't be heard.

It would run on fresh air mode ok, but if I tried it on heating mode it would shut down after a couple of minutes.

Just an idea

 

[trowell]

have you checked the pump ?.had this problem once and trying hard to remember cure.fuel to pump or pump/glow plug

not checked the pump on its own but perhaps I will give it a try

thanks

 

[trowell]

can you hear the pump trying to work during start up phase

i usually hear a ticking sound as it primes but this has stopped.....

 

[Colvic Watson]

I had a D1 with these symptoms. Air had got into the fuel line after running the tank too low. I flashed the power cables across the pump to force it to pump fuel, rather like bleeding a diesel engine, once all the air had gone through and the Eber had diesel, I reconnected the pump and it started up fine.

 

[Martin_J]

If there is no ticking from the fuel pump then it sounds like one of the pre-start checks has failed. The fuel pump will only get energised (by the series of pulses) once flame fail, overhear sensor and glow plug have been checked. Resistance is tested by the controller during the startup sequence..

I would suggest removing the glow plug connectors and checking the resistance across this first.... If you need 'correct' values then let me know and I'll find a link to the manual.

 

[trowell]

If there is no ticking from the fuel pump then it sounds like one of the pre-start checks has failed. The fuel pump will only get energised (by the series of pulses) once flame fail, overhear sensor and glow plug have been checked. Resistance is tested by the controller during the startup sequence..

I would suggest removing the glow plug connectors and checking the resistance across this first.... If you need 'correct' values then let me know and I'll find a link to the manual.

forgive my ingnorance but just to confirm i have understood your kind advice you're suggesting I set my meter to ohms and confirm that there is continuity across the element in the plug? or do you mean i should check the resistance between the two wires that go to the plug. and if you mean the latter, do I do this when the heater has been turned on? yeah...i'm a numpty with this stuff but at least i try!

 

[Martin_J]

I meant to disconnect the glow pin and (with the multimeter on a resistance setting), check the resistance across the two wires coming from the glow pin.

This will measure the glow pin and prove that the element within it is neither broken nor short circuit. The multimeter should show between 0.42 and 0.7 Ohm.

Page 14 of the manual below lists the startup sequence.. showing that checks are made on the sensors and the glow pin before the fan is even spun up...
http://www.espar.com/documents/airtronic.pdf

So - If the fan doesn't spin then check the resistances... If the fan does spin up then see if the timings of the fan starting/stopping correlate with the tables on page 17.

 

[Martin_J]

Just a thought... The temperature control is set to higher than zero (fan only) mode... Perhaps a silly question but had to be asked..

 

[trowell]

I meant to disconnect the glow pin and (with the multimeter on a resistance setting), check the resistance across the two wires coming from the glow pin.

This will measure the glow pin and prove that the element within it is neither broken nor short circuit. The multimeter should show between 0.42 and 0.7 Ohm.

Page 14 of the manual below lists the startup sequence.. showing that checks are made on the sensors and the glow pin before the fan is even spun up...
http://www.espar.com/documents/airtronic.pdf

So - If the fan doesn't spin then check the resistances... If the fan does spin up then see if the timings of the fan starting/stopping correlate with the tables on page 17.

ok thanks Martin I'll give it a try

 

[trowell]

Just a thought... The temperature control is set to higher than zero (fan only) mode... Perhaps a silly question but had to be asked..

yes. i tried it on lowest (fan only) and highest....

 

[rib]

did you not say the fan does spin ?

 

[alteredoutlook]

Exactly the same problem happened to a friends D2 installed in a camper van last winter, and then again in mine this winter.

Both occasions it proved to be the ECU (electronic control unit) was at fault. Replacement isnt cheap!

The part fitted now is meant to be from a different manufacturer than the original and therefore more reliable (eber dont make them, they just get someone else to manufacture them). ..........OR it could be that the originals were not made from bisplate 800 and so liable to break at the earliest opportunity.....perhaps eber are the German equivalent of Rocna....who knows?????

 

[Martin_J]

Alteredoutlook
Out of interest - what exactly were the symptoms when the ECU failed and you tried to start the heater? Fan speed, pump clicks etc...?

Many thanks.

 

[pcatterall]

Sorry to say but this does indeed sound like an ECU problem and a very common one at that. I have several ECUs in a box which are US.
One 'trick' that used to work was if I started the heater by removing the timer and just connecting the red wire to the yellow 'trigger' wire. Sometimes the heater would start.
Effectivly you are bypassing the temp control circuit which may be the circuit ( in the ECU) causing the start up 'check' failure.
Unfortunatly this has only worked for a few more starts then the system reverts to fan only mode. ( I had hoped that it was just the internal temp sensor side which was failing and that I could have used the heaters on an external thermostat)
I can check your ECU if you wish ( You pay postage and £10 to your charity)
New ECU circa ( £220 !!) from Turkey.

 

[alteredoutlook]

Alteredoutlook
Out of interest - what exactly were the symptoms when the ECU failed and you tried to start the heater? Fan speed, pump clicks etc...?

Many thanks.

yes, just that (fan speed, pump clicks and eventual shutdown) - i didnt have a diagnostic device to deduce the error code so took it to www.ribblesdaleauto.co.uk in Preston who replaced it for £332 (ouch! - i'm still trying to forget it) including 1 hours labour.

best of luck with yours

 

[Martin_J]

AlteredOutlook - Sounds like your symptoms were different then... your pump was clicking... I think the OP said they had no pump clicks and I was trying to ascertain whether the fan even started or not...

 

[pcatterall]

If the pump clicks then most of the ecu pre start checks have been done and 'approved' and you may have a chance!!