Webasto Thermo Top: Standheizung für Autos

Hello,

I have a Thermo Top that sometimes malfunctions.

The following behavior:

The heating turns on and starts up normally.

Sometimes it happens that it turns off after a while, but not always.

If I turn it off and then turn it on again, it starts working.

I noticed that it's been producing more smoke shortly after starting recently.

I have the impression that this problem only occurs when the outside temperature is around 0 degrees Celsius.
Could it be related to the diesel fuel? I suspect this problem started after I filled up with cheap gasoline.

Can anyone give me some advice?

Best regards.

Klaus.

Is intermittent biodiesel operation not feasible?

If the heating system is not too old (manufactured before 1998), it can be diagnosed. This allows you to determine the cause of the shutdown.

Possible options include:

- glow stick expired/used up.
- brenner is rusty.
- Flame sensor is rusty or defective.
- temperature sensor defective.
- Insufficient fuel supply.

I've been using a gasoline-powered Thermo Top since 1998, and I haven't experienced any problems whatsoever.

In the TDI, there's an Eberspächer heater, which is also working without any problems.
It shouldn't primarily be due to the fuel; I use fuel from all major brands (no generic brands!).

The Eberspächer doesn't produce any fumes or smoke at all. It only emits a brief, typical heater smell during startup and shutdown. However, the Webasto gasoline heater does the same thing.

CU Gremlin.

Hello,

I had filled up with biodiesel some time ago, and afterwards, the heating system continued to run for a longer period than usual.
The heating system is from around the year 2000 or 2001.
The error has only been occurring for 3 weeks.

Sometimes, when I turn the heating on, I hear a gurgling sound in the heat exchanger. I've tried to bleed the water circuit a few times, but there's still some air in it. Strangely, this has been happening since the heating system was installed, so I think a small amount of air isn't a major problem.

I don't believe the problem lies with the fuel supply; it was already failing before.
At most, it could be that the diesel filter is clogged.

The Bosch technician said that the combustion chamber needs to be replaced.

I tried to disassemble the heating system, but I couldn't get it apart properly.
so that I could remove the combustion chamber.

Where can I get a workshop manual? Or any tips on how to disassemble it?

How can I tell if the glow plugs are worn out? Where is the flame sensor located?

How can I test the temperature sensor?

Greetings.

Klaus.

'Which specific ThermoTop model are you referring to? I might be able to check the documentation at home this weekend.'

Regards,
Private.

Hello,

I don't have the exact name for it at the moment.

I believe it's a Thermo Top DW50.

Best regards.

Klaus.

Hello,

The solution to my problem was a faulty combustion chamber in the heating system.
The combustion chamber contained a blockage that was partially burned or broken off. This likely resulted in the fuel not being distributed properly, leading to incomplete combustion in some areas, which in turn caused smoke formation and, at times, flameout.

After replacing the combustion chamber, which, of course, comes with a completely unreasonable and exaggerated price, everything is working fine again.

Greetings.

Flatscher.

it's a funny error

Thank you for the feedback!

CU Gremlin.

Hello,

Why was the entire combustion chamber replaced instead of just the heating element for 5 euros? Were you at a self-proclaimed authorized Webasto service center that boasts about being authorized but always ends up replacing almost the entire heater?

Best regards,

Golden Pheasant:

So, in the Webasto spare parts catalog, you can't buy the heating element fabric separately. For a Termo Top C/Z, you can't even buy a glow plug individually; you have to buy the entire burner (which costs 70 euros, and they can be much more expensive).
I'm not sure how you're planning to get it out of the burner housing. On my TermoTopC, the burner is assembled with spot welds, so it's not possible to take it apart.

Regards,
Jan.

Hello,

I have to agree with Jan on this.

I remember it from older heating systems, where you could replace the element by itself.

But at 5 euros, the companies wouldn't be making a profit; they want to make even more money. So, I suspect the companies decided to package the whole thing nicely and sell the combustion chamber along with it.

If the benefit of having a heating system wasn't so significant, people should probably do without them. If they did, the demand would decrease, and perhaps the prices would fall.


Regards,

Flatscher.

Hello,

Okay, you're right, I hadn't noticed that before. I just checked the documentation, and the list of maintenance items for the Thermo Top is much shorter than for my Webasto DBW46. The burner felt is not even mentioned here, although it's a wear item.
Als ich letztes Jahr bei Bosch mein Navi neu kalibrieren lassen musste, wollte ich für meine defekte Standheizung eine kleine Fehlerdiagnose bzw. mögliche Kosten für eine Reparatur. Man sagte mir, daß es bei der DBW46 nicht einfach wäre, weil sie keinen Fehlerspeicher hat. Mir wurde eine komplette Austauschheizung für 570Euro zzgl. Umbau recommended.
Okay, I didn't even want to know the price for the 2.5 hours of work. I stopped the process, politely declined, and measured the materials myself.
Diagnosis: Blower fan (95 Euros) needs replacement. While doing this, I also replaced the glow plug (17 euros) and the burner fleece (5 euros). The heating system has been working perfectly ever since. This was my first repair (3.0 hours) on a Webasto heating system, based on documentation.
I'm just wondering why an officially authorized heating and plumbing company can't do the same thing, but seems more interested in ripping off customers! I can also have a complete heating system replaced at a cheaper, independent workshop; there's no need to go to Bosch for that.

Best regards,

Well, they probably don't want to get their hands dirty with small jobs. My TermoTop C also stopped working recently. It would always trigger a safety shutdown before even attempting to start. I suspected the glow plug, as it also serves as a flame sensor in the TermoTop C. I went to Bosch, and they said that the glow plug never breaks and that it was definitely the control unit. However, the control unit is only available as a complete unit with the heat exchanger (around 350 Euros ). Then I tried connecting a load resistor instead of the glow plug, and sure enough, it tried to start. So, it was really just the glow plug. I then found a used one for 40 Euros (including the burner) .

Jan03 wrote:

Well, they probably don't want to get their hands dirty with small tasks. My TermoTop C also stopped working recently. It would always trigger a safety shutdown before even attempting to start. I suspected the glow plug, as it also serves as a flame sensor in the TermoTop C. I went to Bosch, and they said that the glow plug never breaks and that it was definitely the control unit. However, the control unit is only available as a complete unit with the heat exchanger (around 350 Euros ). Then I tried connecting a load resistor instead of the glow plug, and lo and behold, it tried to start. So it was really just the glow plug. I then found a used one for 40 Euros (including the burner) .

With my Eberspächer B4WSC (currently unused in the basement), I have already worn out 2 glow plugs. I have now purchased the modular timer with diagnostic function so that I am not dependent on the workshop. Your experience confirms that.

mcgregg