Eberspacher D2L wont turn off

[Lee1972]

I recently got my old petrol Eberspacher D2L working, but now I cant turn it off!
Its blowing hot air, and I have to disconnect it from the leisure battery to bring it to a halt.
Any suggestions?

[Smcknighty]

Dunno - I'm guessing things are getting pretty hot by now. At least it's a cold night?


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[pirate-pete]

Are you using the three way switch on thermostat next to the ashtray to turn it on/off?

If so do the leds still light up when in centre (off) position? If so sounds like dodgy thermostat unit but I don't think the early ones are too complicated inside.

What happens if you turn thermostat to lowest setting. Will that shut it off?

Not sure about petrol ones but with the diesels the early Westy thermostats shut off fuel completely when set temp on stat is reached. The later ones cut the fuel to keep it ticking over at low heat to save on restarting from cold using glow plug when the stat calls for heat again. I guess that behaviour not really needed with petrol so wondering if they should shut off fuel completely when stat set temperature reached.

[ZsZ]

How long did you wait before you plugged off?
These heaters have a cool down cycle, so they run for a while without the pump running to clean/cool the combustion chamber.
If the pump was not switching off then the ECU gone mad.

[Lee1972]

Are you using the three way switch on thermostat next to the ashtray to turn it on/off?

If so do the leds still light up when in centre (off) position? If so sounds like dodgy thermostat unit but I don't think the early ones are too complicated inside.

What happens if you turn thermostat to lowest setting. Will that shut it off?

Not sure about petrol ones but with the diesels the early Westy thermostats shut off fuel completely when set temp on stat is reached. The later ones cut the fuel to keep it ticking over at low heat to save on restarting from cold using glow plug when the stat calls for heat again. I guess that behaviour not really needed with petrol so wondering if they should shut off fuel completely when stat set temperature reached.

How long did you wait before you plugged off?
These heaters have a cool down cycle, so they run for a while without the pump running to clean/cool the combustion chamber.
If the pump was not switching off then the ECU gone mad.

Thanks for the response chaps, much appreciated!

The three way switch stays green on all settings, while the heaters running.
If I turn the Thermostat to its lowest nothing happens (but maybe I should be waiting longer??)
I'll leave it running later to see if it turns off automatically from the stat, once the temperatures reached, to see if that works.

..Hope its not the ECU, they're hard to get 2nd hand I've heard!

[pirate-pete]

Here is a translation from the german B2L manual

Functional description

Run after power on / start normal

Switch on: Green indicator light on room temperature controller "On"

After max. 3 seconds: Blower at full speed "On”. With Diesel the glow plug on. With Petrol the incandescent filament and spark plug on.

After approx. 30 seconds: Fuel pumping "On"

After approx. 90 seconds: thermoswitch switches off glow or glow spark plug.
(When heat exchanger is warm)

Now the heater runs with full heat, and the hot air heated by the heat exchanger passes through the air outlet into the room to be heated.

When the temperature set at roomstat is reached the following happens

B2L (Petrol)
The fuel pump is switched off. The residual heat still present in the heating device until the end of the normal overrun (approx. 3 minutes) with full fan speed, then with reduced fan speed, into the room

After the room temperature has fallen below the temperature set at the room temperature controller, the room temperature controller switches the fuel pump on and a new cycle begins

A built-in glow spiral switch ensures that the spark plug is switched off in normal control mode, when the ignition sparks are sufficient for flame formation

To turn off…

The green warning light goes out when this is switched off. This is followed by the after-run of the blower for cooling. It is automatically terminated by the thermoswitch.

I'll have a look to see if I still have a spare ECU I found in my van when I bought it. There were two and neither worked with my diesel so I found one with the correct part number on German eBay to get mine running. One of the spare ones was later found to work to my surprise when tested in someone else's petrol van. If I haven't sold in on you can try it if you are near me.

Somewhere too I think I have notes on how to bypass the thermostat to rule out problems with it. Think it was a case of unplugging the stat and jumpering together a couple of the connections. The extra connections would be to light the leds or something. Will see if I can find that too but not got the time right now.

[Lee1972]

Here is a translation from the german B2L manual

Functional description

Run after power on / start normal

Switch on: Green indicator light on room temperature controller "On"

After max. 3 seconds: Blower at full speed "On”. With Diesel the glow plug on. With Petrol the incandescent filament and spark plug on.

After approx. 30 seconds: Fuel pumping "On"

After approx. 90 seconds: thermoswitch switches off glow or glow spark plug.
(When heat exchanger is warm)

Now the heater runs with full heat, and the hot air heated by the heat exchanger passes through the air outlet into the room to be heated.

When the temperature set at roomstat is reached the following happens

B2L (Petrol)
The fuel pump is switched off. The residual heat still present in the heating device until the end of the normal overrun (approx. 3 minutes) with full fan speed, then with reduced fan speed, into the room

After the room temperature has fallen below the temperature set at the room temperature controller, the room temperature controller switches the fuel pump on and a new cycle begins

A built-in glow spiral switch ensures that the spark plug is switched off in normal control mode, when the ignition sparks are sufficient for flame formation

To turn off…

The green warning light goes out when this is switched off. This is followed by the after-run of the blower for cooling. It is automatically terminated by the thermoswitch.

I'll have a look to see if I still have a spare ECU I found in my van when I bought it. There were two and neither worked with my diesel so I found one with the correct part number on German eBay to get mine running. One of the spare ones was later found to work to my surprise when tested in someone else's petrol van. If I haven't sold in on you can try it if you are near me.

Somewhere too I think I have notes on how to bypass the thermostat to rule out problems with it. Think it was a case of unplugging the stat and jumpering together a couple of the connections. The extra connections would be to light the leds or something. Will see if I can find that too but not got the time right now.

Great Stuff.. Cheers.
I'll give it another test run today to see if the green led goes out when switched off.
The ECU has the following numbers on it: 201607 50 00 00 (12 volt)

[pirate-pete]

The German manual I was working from is the same as that here http://www.t3-infos.de/images/Eberspaecher_B2L_D2L.pdf


Page 18 has the details on how to make a test lead to bypass the control thermostat and the following pages have a troubleshooting guide but in german. Google translate useful as is OCR software to grab the text from the pdf to paste into google translate.

I looked all over for my spare ECU yesterday but could not find it. Only photos and also a faulty thermostat control unit. One ECU I had was the exact same one as you mention 20 1607 50 00 00. Looking at that guide it seems if the number starts with 20 it is for petrol and if it starts with 25 it is for Diesel so that might explain why it worked in a petrol but not in my van. The ECUs I think still show B2L/D2L on the side. The other one I had was smaller than your one and was 25 1597 500000 but can also understand now why that didn't work as it was for a later diesel heater which reduces fuel flow to 25% when it reaches set temp. It seems from the wiring diagrams these ones also need an updated circuit board inside the heater itself.

[Lee1972]

The German manual I was working from is the same as that here http://www.t3-infos.de/images/Eberspaecher_B2L_D2L.pdf


Page 18 has the details on how to make a test lead to bypass the control thermostat and the following pages have a troubleshooting guide but in german. Google translate useful as is OCR software to grab the text from the pdf to paste into google translate.

I looked all over for my spare ECU yesterday but could not find it. Only photos and also a faulty thermostat control unit. One ECU I had was the exact same one as you mention 20 1607 50 00 00. Looking at that guide it seems if the number starts with 20 it is for petrol and if it starts with 25 it is for Diesel so that might explain why it worked in a petrol but not in my van. The ECUs I think still show B2L/D2L on the side. The other one I had was smaller than your one and was 25 1597 500000 but can also understand now why that didn't work as it was for a later diesel heater which reduces fuel flow to 25% when it reaches set temp. It seems from the wiring diagrams these ones also need an updated circuit board inside the heater itself.

Thanks Pete, That's a great diagram!
I've actually managed to get the heater working! ...not sure what happened but the thermostat just seemed to start working after running the heater for a while, once i started turning the dial up & down a few times.
I guess it was just not clicking, after not being used for more than 10 years
Thanks for all the help chaps!!