Webasto Air Top 2000 std diesel.

Hi was wondering is anyone here has experience with this particular model....title should read STC not STD!

Been saving up for a while for one of these to keep the dogs warm...now all installed .....BUT

On initial start up goes through cycle but no pump noise, just the fan running ....no voltage on power supply to fuel pump and pump does not prime (perhaps a max of 132mA but hunting around like disconnected) faultfinding one long flash and five shorts flashes ie NO START

Next...disconnect pump and try a direct power supply on pump, just one clunk when connected not running continuosly but not sure what to expect....anyway operate it enough to get the fuel through, fill the tiny fuel filter so..... reconnect pump to Airtop and switch on.....immediately fires up and I get heat and the sound of a tiny jet airplane starting up....all good BUT still no power to pump so pump doesn't run so it eventually shuts down and shows 7 long flashes and 5 short flashes which indicates fuel pump interrupted or short circuited. So I switch off...

So what should I expect from the fuel pump when directly connected to an independent power supply, noisewise operationwise etc and why do I not get 12v supply to it from the Air Top at any point....sounds like an internal problem or am I being thick? Or do I have a pump problem and an internal airtop problem

If you are still reading, well done....hope this makes sense....can anyone help....

You may have one already if not it could be useful.

http://www.suremarine.com/manuals/webasto-repair-manuals/at2000st-repair.pdf

Thanks Tim,
thanks for posting, it will be a useful resource in the future. Shame it doesn't give expcted voltage readouts for the fuel dosing pump....I'm guessing it is probably the control unit inside is somehow faulty and not sending voltage to the dosing pump as it seems like an open circuit when it should be calling for fuel and activating the pump.

Naturally I am not a qualified Webasto installation engineer therefore the warranty on this new bit of kit will be void....as Ive installed it myself...it's what happens when you try to save money and do it yourself.....only answer is to go cap-in-hand tp my local webasto installer and ask for help....sounds expensive

I am sorry I cannot be of any more help. I had previously looked up the information on the Webasto site because I was thinking of doing just the same as you.
Good luck, if there is a fault I hope it is theirs and the repair is free to you.

Thanks Tim, I will post to show how I get on. I bought through Butler Technik and have just posted a tech help question to them. Fingers crossed they are helpful...

If and when I eventually get it working I will post up all my installation pictures as a step by step thing. I have it positioned below the cubby box....a local fabricator is knocking up an aluminium box for me for not a lot of money which I will modify for vent holes fuse holds switches etc....but with ease of access for when this has got to be serviced

Mate, I have one of these. I had the same fault code and couldn't work it out until I looked at the box. To do that I had to remove the toolbox I had on it! Then it worked, so make sure nothing is resting on it. They're also power hungry so make sure you're battery is charged up or try it with the engine running.

Thanks for that, no weight on it but good to know about the power thing, I'd hate to not be able to start the old girl...might get a second battery and a bit of monitoring

The heater ecu supplies a pulsed supply for the fuel dosing pump.
You may have locked it out, worth a google for how to reset it.
Again a search will tell you minimum voltage needs.

Hi Lynall, the same Lynall from the series 2 club? That is a very good idea....I've just been outside measuring the pulsed supply....after I turn the heater on I get a steady 6mA's then when it obviously calls for fuel it ramps up in stages all the way up to 157mA's then after it realises it's not getting the fuel it shuts down and going through what should be the cool down phase it returns to a steady 6mA's. Checked all connections in the heater and all are good.

I have googled for these figures but I haven't search for fuel lock out or fuel pump lock out....def work a go. There will be an answer...this time I'm going to enjoy the troubleshooting journey

157mA seems like bugger all to run a pump albeit a pulsed pump

Cheers

Yes same Lynall!
Milliamps mean swfa to me I would try it with a 21 watt bulb that way at least its got something to work against/load.
If the heater ecu is not putting out a supply it thinks something else is wrong.
Ive not had any dealings with the airtop, came across them in trucks but 99 percent of them are eberspacher models.
Lods of cars have the webasto thermo models incl land rovers d2/d3/d4 freelander etc so there might be more info available on them?

Meant to add Ive got the thermo top one on my D3 as std fit and Iirc after three failed starts it locks itself out and requires a reset.

Chapter 15 tells you what to do

http://www.sales.butlertechnik.com/techdocs/Webasto Airtop 2000ST Installation Instruction.pdf

Looks like taking the fuse out and replacing it with the unit switched on resets it.
From chapter 15:
To reset the fault switch the heater on and off briefly (at least 2 seconds).
If serious malfunctions such as overheating or failure to start reoccur, the heater is locked (F 12) and can be put back into service by disconnecting the power supply with the heater switched on (e.g. by removing and reinserting fuse).

Thanks everyone....yes am aware of the full reset which I have done a few times...thought there might be a separate fuel reset...which got me excited....... checked connectors, checked continuity I'm pretty sure it's a fubared ecu/control unit 150mV I keep saying milliamps when I mean millivolts....get to speak to the head tech at the company that sold it to me tomorrow and will probably send it back for them to test.

Picked up my nicely made aluminium enclosure for it today.....will work out how to post photos soon

Thinking of your millivolts, is the pulse to quick for a std voltmeter to get a sensible reading?
Have you tried it with a bulb?

that could be a possibility.....i'll wire up a bulb tomorrow..lthanks Lynall