eberspacher misbehaving.

Hi there.
I have a Trident and my diesel heater is misbehaving!
So when I turn on the eberspacher it makes a few clicks, then fails to start.
I eventually found that by just disconnecting the leisure battery terminal and reconnect it then fires up no problem and works fine throughout. However when I start the engine up its back to square one again. 
Does anyone have any idea what is going on or have you suffered a similar issue and what resolved it?
All wires are connected as they should be and the fuses are all working too.

PS all electrical systems that run off the leisure battery are working fine.

Regards Rob.

Have you measured the battery voltage when it and other 12V appliances are on? It's only one of a number of possibilities, but I think on most models they will "lock out" within 20s if the battery voltage drops too low. This is typically 10.6V at the heater, but with losses in the cabling with the glow pin activated, I think you could get that with a battery voltage in the low 11.xV range.

If that looks good, I'd recommend following the troubleshooting guidance for your model, as published by Eberspacher. Here's an example, but note it's for an Airtronic D5 - yours is probably a different model:

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If nothing obvious leaps out at you from that, it may be necessary to get someone with a diagnostic code reader to take a look at it, and get it to tell you what it thinks is wrong. Some types of thermostatic control incorporate a code reader function, but you probably have a simpler one if it's just the default A/S installation.

The Eberspacher diesel heater needs a voltage above 11.75V to fire up properly. In my experience if the voltage is low the fan comes on briefly than shuts off. What you describe suggests a poor electrical connection or you have a dying leisure battery.

Perhaps check you battery voltage with a digital meter, then see what battery voltage is when you turn on the Eberspacher heater, do this also when you start the motor, this will also show what the van's alternator is pushing out. It could be there's a loose connection somewhere, even an engine earth strap that's corroded. I could imagine a heavy current stressing a poor contact that reconnects when less current is flowing. At times like this having an assistant to help can be an advantage, plus pen and paper to write down the voltages.

Thanks for the help guys. 
Well i did have a new alternator fitted due to failure 3 weeks ago. I have been out in the van a few times since then it could be that.
However I do have a battery monitor (Bluetooth) and I initiated the Eberspacher today with the monitor app.
Here’s what I got. Everything started without issue today for the first time.
The first drop in voltage is the heater initiating. Then the heater starting, then the plateau is the heater going into “tick mode”, the the last spike is the heater shutting down.[You must be registered and logged in to see this link.]

I suppose it would be nice to see you have a voltage between 14V and 14.5V when the engine is running. Your alternator should be OK because it's new, there's still the matter of having a proper functioning earth strap.

I had no end of bother in the past when a garage failed to refit the earth strap after an engine rebuild.

My experience may help here. If your van is a fairly early example with Eberspächer heating it may be suffering the same problem that I had. On trying to start the heater it would begin the cycle but the high initial current draw would bring it the voltage down below cut out level and so the process would stop. Then, as the battery recovered the heater would try again only to go through the same process.I spent some cold nights in my Symbol as a result. The answer turned out to be quite simple but necessitated my van going down to Eberspächer in Hampshire to be sorted.
It turned out that the charging lead from the alternator was not man enough for the job and although the voltage was nominally correct it was a "thin" charge that was easily defeated. The cure was to increase the charging capacity by way of thicker wire since the distance to the battery was enough to drop current, thus preventing a full charge. This worked for my van.
Looking at the graph that seems to describe this as well.

This is what happened when we had a Duetto. At an ASOC AGM I learnt that A-S hadn't used a thick enough wire to feed the Eberspächer, causing the voltage drop at start-up. I booked our van in at A-S in Willersey and afterward the heater behaved better. Off EHU running the Eberspächer does test your 12V system, if the battery is not fully charged or on its last legs it will show up.

well fourth attempt at startup today and no issues. I think it was the alternator.
I had it checked as the van battery was struggling to keep above 12.5v and the leisure battery was struggling to keep above 12.6v.
So i think a good few runs out may have sorted it.
I’ll add another post if things kick off again.
Thank you for all the help and im sure this thread will be good reference for others.

Regards Rob.

Cold weather exacerbates the problem as a cold leisure battery is less likely to have enough oomph even if ok once it's slightly warmer. My heater doesn't start if the battery goes below 12.3V during the test phase. A few times I've had to start the engine to kickstart the heater, but haven't had to do that since replacing my leisure battery. Increasing need to do this told me it was time to replace the battery.

Just had a week in chilly Scotland (minor puddle-freezing overnight) and my new battery allowed the heater to start first time every morning so van nice and toasty by the time I was ready to get out of bed.