Auxiliary heater leaking diesel

Hello everyone,
I installed a new Webasto Thermo Top T DW 50 auxiliary heater in my Passat TDI (manufactured in 7/94). However, after the initial start-up, it's not working as it should. It doesn't always ignite. And when it does ignite, it smokes for the first few minutes. Is this normal? Perhaps it needs to be 'broken in' first? How long does that take?
If it doesn't start, I notice a little bit of diesel leaking out (from the bottom). Is that normal?
Installation is correct, but is there any risk of fire due to diesel residue?
I haven't installed many SHs yet, actually this is the first one , maybe there's a specialist among you.
Thank you for your responses.
Okay, hier ist die Übersetzung:

'josi'

HI,

My new auxiliary heater also smokes for the first few minutes after it starts.
Are you sure it's leaking diesel? The exhaust muffler has a small opening at the very bottom in the seam to allow condensation to drain. Right after the engine starts, a significant amount of water condenses inside the muffler (and not just there), which then drips out.
It doesn't smell like pure water, but rather like diesel and exhaust fumes.

Regards,
Sure, here is the translation of the text from German to English:

'Micha'

Hello,
Damn, it didn't ignite again today. The SH is humming and ticking, it's puffing out cold smoke from the exhaust for a few minutes, and that's it. Then the fan runs for a while afterwards. Does that mean there's diesel residue on the bottom of the heating unit, and that the diesel being blown out of the combustion chamber by the fan?
It probably won't ignite until the fault is cleared. What could it be? 'Pornographic website charges €35 for a single viewing = 15 minutes!'
If they really have to achieve something, I might as well buy three used ones right away. Buy heating devices for that purpose.
The heating system is new and has a warranty. @Micha, thanks for the quick reply, did yours do the same thing?
Regards,
Josi.

No, it's normal for them to smoke briefly when ignited, but not for several minutes.
There might still be air in the supply line. Have you followed all the installation instructions?
Otherwise, let's start the diagnosis (or have it started).

@Josi:

You can remove the interference shielding yourself. You don't need a Bosch service for that.

Regarding starting: When you press the start button, the SH blower starts first. It runs for approximately 1 minute before the fuel pump starts. (The DW 50 will also not allow diesel to enter the combustion chamber any earlier.) The speed at which the heater stabilizes and stops producing smoke depends on the routing and length of the exhaust hose.
When I open the hood and it's really cold, I can sometimes see a little bit of smoke for up to a minute after the engine has been started.

Regards,
Sure, here is the translation of the text from German to English:

'Micha'

Hi,
Yes, I know about the fault clearing process. I'll try it again tomorrow.
The installation must be correct, because the device is already running and has its own tank.
I'll call the Webasto hotline on Monday.
I can't really imagine that the heating device is faulty; there must be something else going on.
Disassemble and send it in - then winter will be over, and that's that.
Well ,
Regards,
Josi.

Hello everyone,
Here's the latest status:
Just after making 10 calls, attending meetings 4 times, driving 700km, and taking 2 days off, things finally start to move forward!
Mo: 1. Service: Appointment only available next week. 2. Service: Mechanic not available! Please come back tomorrow! W-Hotline: busy.
Di: W-Hotline: busy. *Mechanic on duty, immediate diagnosis based on symptoms: heater defective, warranty processing through W. According to the boss, this is not possible; it must be done where it was purchased. So, I drove there after a phone call, covering 330 km. I have to say, they made an effort. Test run: the heater works (water is warm). When removed from the bracket, the smoking stopped. So, the smoking was due to diesel residue in the exhaust. The device probably won't ignite if the water is cold, so I went for a walk for an hour and then tested it again: the device still doesn't ignite!!
Heating unit removed, various tests performed on the test bench, heating unit defective.
'Tires went flat on the car, started the drive home - heavy snowfall, traffic jam, stuck for 6 hours. According to [someone/something], the heater is...' 'The boss sent the repair via mail after the warranty repair, that's a great statement.'
In this sense,
Josi.