Webasto Diagnostics.

[Brian422]

I suspect the Combustion Air Fan is faulty; no turbine whine on start, Water Pump working, but I'd like to make sure before going any further.

Unfortunately the cost of Webasto diagnostic device is really expensive.

I'd be grateful for any feedback from users of device linked below:-

 

https://www.ebay.co.uk/itm/402121622145

 

Regards and Thanks

Brian.

[Opener]

Do you not have a flashy light on/next to your on/off switch? I have a simple pilot on the switch. 

Some idiot (OK, me) turned the diesel off when leaving the boat and forgot to turn it back on. Shiny new Webby worked for a short while - about a pipes-worth of fuel on return -  then shut down. Sequence of flashes on switch indicated 'fuel'. Cue inspiration "I know what I've done ...."

[Tom and Bex]

On 16/11/2022 at 14:11, Brian422 said:

I suspect the Combustion Air Fan is faulty; no turbine whine on start, Water Pump working, but I'd like to make sure before going any further.

Unfortunately the cost of Webasto diagnostic device is really expensive.

I'd be grateful for any feedback from users of device linked below:-

 

https://www.ebay.co.uk/itm/402121622145

 

Regards and Thanks

Brian.

I use very similar by modifying my existing vag-com lead (for diagnostic use on VW group cars). Got the details from a Russian Internet forum translated by Google translate! Worked OK with 2 different era eberspacher heaters, not tried with webasto. 

[Brian422]

Thanks for your suggestions and thoughts.

 

I don't have a dedicated power switch just a Timer with manual override for instant operation.

 

Interested in vag-com suggestion as have RossTec; will investigate.

 

Regards

Brian.

[Opener]

4 hours ago, Brian422 said:

Thanks for your suggestions and thoughts.

 

I don't have a dedicated power switch just a Timer with manual override for instant operation.

 

Interested in vag-com suggestion as have RossTec; will investigate.

 

Regards

Brian.

Hmm? How do you know when it's 'on', apart from the obvious noise/heat? Do you not have at least a pilot light indicating on/off?

I only have an on off with a built in pilot. When it's on the pilot is on. If it doesn't 'fire up' that pilot flashes and the pattern of flashes translates into a diagnosis of a fault.

Do you just turn up your timer/override and wait for noise/heat?

[Brian422]

Hi Opener. The short answer to your qustion is yes. Pressing the timer override illuminates the Timer display, then just it's listen and wait.

Unfortunately there's no flashing lights indicating fault code.

[chevron]

I bought that kit on ebay from that seller wish I had paid the few pounds more for one he does with diagnostic connectors to make it simpler. Works perfectly on my windows laptop. Fast delivery as well.

[Brian422]

Hi Chevron. Thank you for your advice and guidance.

 

Will order kit with additional leads.

 

Regards

Brian

[Brian422]

Diagnostic kit took 6 weeks to arrive but given the distance and current postal strikes quite understandable.

Haven't yet used because away from boat and Webasto is current sitting on bench.

 

Dismantled Combustion Fan housing, found motor seized and what looks like oil residue, not diesel, possibly from fan bearings inside housing.

Have purchased replacement.

Just hoping that motor didn't draw excess current and damage electronics.

 

Unfortunately removing motor for further examination would mean damaging fan. Perhaps will when curiosity gets the better of me.

 

Regards

Brian.

[Brian422]

Update:

Managed to remove Combustion Fan Motor from housing without damaging Fan. Quite a lot of oil on gasket and between gasket and housing; bolts securing motor to housing were loose.

 

Shaft rotation notchy - possibly commutator or damaged bearing; source of oil.

 

Still no joy in getting W.T.T. to communicate with Webasto; haven't given up yet!

Edited February 9, 2023 by Brian422

[Tractor]

This is a job which I need to do; getting a diagnostic connected to read 'Webasto Thermotop C diagnostics that is. Reluctant to order the kit without some confidence that it will work, and communicate.

Interested to see how this works.

 

 

[Brian422]

I've attempted multiple new installs without success. Having requested details to enable items return have been contacted by seller and given step by step instructions. I'm not convinced as software is more focused on W-Bus protocol; my Thermo Top C is the Analogue version. However, will follow instructions and report back on results.

[matty40s]

This is why we pay for the proper Webasto diagnostic kit, and software, with full technical backup from Webasto if needed, so you guys can enjoy your boating and get your Webastos fixed properly.😁

[Tractor]

Thanks Brian, grateful for the feedback.

I have Thermotop C, not sure if this is an analogue device?

 

[Brian422]

 

Top PCB is Analogue, Bottom W-Bus.

Connections mentioned in Workshop Manual are for analogue only: 

 

Edited February 10, 2023 by Brian422

[Brian422]

21 hours ago, matty40s said:

This is why we pay for the proper Webasto diagnostic kit, and software, with full technical backup from Webasto if needed, so you guys can enjoy your boating and get your Webastos fixed properly.😁

Purchased kit before attempting Webasto repair but only required Webasto Trouble Shooting Guide.

 

Purchased Ross Tech Full VCDS shortly after buying VW saloon because as we all know modern vehicles are complex, unlike Webasto Water Heaters, and without diagnostics it's impossible even to diagnose any problems. I use VCDS regularly just to keep an eye out for any potential problems. Thinking o purchasing OBDEleven for convenience.

 

If I was servicing Webastos regularly then I would purchase 'proper' Webasto diagnostic kit but as it might not be used more than once or twice a year .... .

 

[T_i_m]

On 09/02/2023 at 17:51, Tractor said:

Thanks Brian, grateful for the feedback.

I have Thermotop C, not sure if this is an analogue device?

 

Hi, did you / Brian / anyone get any further with this?

 

I believe Thermo Top C's can be both analogue and not but the only difference id how they are triggered on.

 

Ie. On the 'analogue' one it's a dedicated pin that takes a switched 12V from a timer or thermostat where the non-analogue takes that instruction via a data bus, possibly the 'W-bus' as I have seen that mentioned a lot and I think you can buy converters that take an analogue 'On' signal and send the relevant code over the bus.

 

I believe the genuine Webasto diagnostic and the generic USB <> OBD interfaces need to be 'K-Line' or 'K-bus' to talk to the diagnostics of the Webasto Thermo Top C analogue models (and possibly the others).

 

Incidentally, if you run V3.18 of the Thermo Test software and choose one of the older heater, it drops back to the older (V2.16 or summat) version.

 

If you check out a generic OBD vehicle interface it normally gives:

 

12V on pin 16

Signal Gnd on pin 5 (possibly 4)

Data on pin 7 that is often labelled as ISO9141 / K-Line.

 

The problem is (and this is all as I understand it), most vehicle diagnostic software can switch the 'active' data in to some of the other bus pins but the Webasto software can't, assuming it's just going to be there (on Pin7). So, whilst it might be possible a generic / multi protocol / bus vehicle OBD adaptors might work on a Webasto, it might only be if they default to reading the data on Pin 7 and decoding it as K-Line / KKL / 409.1 etc.

 

I've bought the basic USB <> OBD K-Line adaptor, have a mating in-line plug kit in my box of bits and a couple of largish red / black clips ready to wire up to the plug to duplicate the live end of the test loom. I'm just not sure what the format is of what I believe to be the diagnostic port on the Webasto Thermo Top C (analogue) as fitted to a NB a good few years ago.

 

 

The eBay diagnostic kits come with a small insulated alligator clip for the diag pin but I can't see that being of direct use on the std port (it could be OK if you are playing with one and just have a bit of stripped wire sticking out of the diagnostic port etc). I think a fine probe might be better, assuming you can get a good connection etc.

On 09/02/2023 at 16:50, Brian422 said:

I've attempted multiple new installs without success. Having requested details to enable items return have been contacted by seller and given step by step instructions. I'm not convinced as software is more focused on W-Bus protocol; my Thermo Top C is the Analogue version. However, will follow instructions and report back on results.

The CD that presumably comes with the driver for the KKL / K-Line OBD interface was broken but my laptop appears to have see the USB interface and presented it as COM:5

 

However, whilst there is what looks like a single red LED on the interface, it doesn't light up from just being connected to my laptop but I can try it into the car and see if it does (so it might just indicate 12V present).

 

Then it's just a matter of telling the Webasto Thermo Test software that the device is on COM:5 and crossing your fingers.

 

That's why I was thinking of buying a known working Thermo Top C (ideally analogue but you can buy an analogue to W-Bus converter from eBay for about 50 quid)  just to be reassured that my test software was working (and maybe having a spare for my Nb mate).

Edited February 28 by T_i_m

[Brian422]

On 28/02/2025 at 10:18, T_i_m said:

I have Thermotop C, not sure if this is an analogue device?

Apologies for late reply.

My Webasto Thermo Top C has an Analogue control p.c.b but I understand it can be converted to digital but haven't investigated further.

 

Diagnostic kit purchased from E-Bay appears, from various Youtube videos to be more suitable for digital vehicle protocols. 

 

VCDS uses access to the vehicles CanBus via OBD2 port.

[T_i_m]

23 minutes ago, Brian422 said:

Apologies for late reply.

My Webasto Thermo Top C has an Analogue control p.c.b but I understand it can be converted to digital but haven't investigated further.

 

Diagnostic kit purchased from E-Bay appears, from various Youtube videos to be more suitable for digital vehicle protocols. 

 

VCDS uses access to the vehicles CanBus via OBD2 port.

Hi Brian and thanks for the reply, especially to an older thread. 😉

 

I have since been able to run the Webasto diagnostics on my friends Thermo Top C, using a basic 'K-Line vehicle OBD interface' with a small additional loom giving me +12V on OBD Pin 16, sig Gnd on OBD Pin5 and 'data' on OBD Pin7, connected to the single flying connector on the boat / Webasto loom.

 

 

We cleared the fault codes and then ran the output tests (circulation pump, fan, glow plug and fuel pump) and all seemed ok.

 

We then started the heater and it ran for about 30 minutes taking the temperature from 15 to 32 DegC but not really seeming to get going at full power.

 

 

Sometime in the next half hour it shut down and with the following fault:

 

 

I wanted to run the fuel pump test in the diagnostics but before I could he removed the heater and disconnected the pump from the supply tank?

 

So we stripped the heater down anyway and whilst the main heat exchanger was a bit sooty, I've seen worse on Youtube. I also tested the burner by blowing though it (as per another YT diag vid) and it didn't seem to be blocked. That said, the diffuser mesh in the burner did look a bit tired and was partially blocked.

 

He has since give it a good clean so it's just a matter of testing the pump and if it's ok, decide if to get a replacement burner or open this one up and replacing the diffuser ourselves.

 

It also turns out that between it working and it not, he had topped up the heater fuel tank from very low (stirred up some debris in the tank and with no filter in the heater fuel line), clipped something solid sticking out from the bank (giving the boat / tank a shake) and melting a fender that ended up over the heater exhaust (potentially when it was working properly (/better?)).

 

I believe all the Webasto heaters use a similar diagnostic interface protocol and the 'digital / analogue' thing is more about how they are turned on / off etc.

 

So as you said you can get a small external box that takes an analogue trigger and produces the right data to turn a digital (control) heater on. That would allow someone needed basic analogue on/off control to make use of an ex-vehicle W-Bus triggered heater.

 

Edited March 12 by T_i_m

[Brian422]

Just as a by the way I've heard that Webasto recommend heater used at least once a month throughout the year and that using Paraffin occasionally helps remove carbon as Paraffin burns at a much higher temperature.  

[T_i_m]

2 minutes ago, Brian422 said:

Just as a by the way I've heard that Webasto recommend heater used at least once a month throughout the year and that using Paraffin occasionally helps remove carbon as Paraffin burns at a much higher temperature.  

The monthly usage sounds sensible, keeps things ticking over etc and is the paraffin tip from Webasto Brian?

[ditchcrawler]

17 minutes ago, Brian422 said:

Just as a by the way I've heard that Webasto recommend heater used at least once a month throughout the year and that using Paraffin occasionally helps remove carbon as Paraffin burns at a much higher temperature.  

I do similar with my heating at home, it comes on briefly all through the summer

[T_i_m]

35 minutes ago, ditchcrawler said:

I do similar with my heating at home, it comes on briefly all through the summer

When my mate and his family went to their holiday home in Spain for the summer he would ask us if we would water the plants, check the mail and give the cars a run. I didn't mind driving the (new) Mini Cooper S but wasn't so keen to take the Discovery or Rolls out.

 

They are nice cars an all but the 'risk' of something happening to them whilst in my care, even if not my fault (and him saying 'That's what the insurance is for') was more stress than any pleasure I might have got out of driving them (and I didn't, particularly).

 

Mind you, it was a similar thing when my mate handed me the tiller of his 70' home, on when then felt like a very narrow river (canal) and disappeared inside!

[Brian422]

Quote

The monthly usage sounds sensible, keeps things ticking over etc and is the paraffin tip from Webasto Brian?

Don't think it was from Webasto but using a fuel that burns at a higher temperature to clear carbon does seem logical.

However willing to be convinced otherwise.

From Crown Oil (Fuels and Lubricants).Paraffin vs Diesel:

Kerosene has a lighter viscosity than regular diesel, which makes it burn at a hotter temperature in an engine or boiler (and therefore more efficiently) than diesel. However, as it burns drier and with less lubricity than diesel due to its lower aromatic compound content, fuel pumps, gaskets and valves may experience greater wear when running on kerosene.

[T_i_m]

Just now, Brian422 said:

Don't think it was from Webasto but using a fuel that burns at a higher temperature to clear carbon does seem logical.

However willing to be convinced otherwise.

From Crown Oil (Fuels and Lubricants).Paraffin vs Diesel:

Kerosene has a lighter viscosity than regular diesel, which makes it burn at a hotter temperature in an engine or boiler (and therefore more efficiently) than diesel. However, as it burns drier and with less lubricity than diesel due to its lower aromatic compound content, fuel pumps, gaskets and valves may experience greater wear when running on kerosene.

Again, thanks for the reply and info.

 

I suppose under 'normal / ideal' circumstances these heaters shouldn't coke up and if this one hasn't ever been stripped (and I don't believe it has in the 10 years my mate has owned the boat), it was actually pretty clean inside (and certainly compared with some I've seen on YT that are really coked up).

 

So I think it might just be a combination of 'wear and tear' (the burner diffuser becoming blocked) from a combination of the inevitable carbon deposits you get with combustion and possibly (/likely?) debris getting into the diffuser because there has been no fuel filter fitted?

 

I have the burner here and when I get my Dremel back I'll try cutting it open and replacing the diffuser and pad. Tack it back together with the MIG and see how we go.

 

I firstly need to get the sheared screw out of the heat exchanger. ;-(