Auxiliary heater - how does it work?
 

Hi there,

I have a left hand drive ex-germany car that is fitted with the auxiliary heater that has the timer control window just forward of the gear stick. I have no idea how it works or whether it works!

I am trying to find some instructions and also details of where the fuse is so I can get it working now the cold weather is here.

If anyone can tell me how it works and how to trouble shoot it (no life from the display) I would be grateful.

Cheers

Tobyd

I found this reference to the heater on an obscure web page -


'The auxiliary heater (Zusatzheizung, code 228) is a separate heating
system that works independently of the engine. It consists of a
separate burner unit, an electric water pump, a control unit and it
is connected to the coolant circulation of the engine. It is run on
the fuel of the car (either diesel or petrol, these are different
units for obvious reasons) with a separate fuel line from the tank.
This makes it independent from an electrical outlet and from the
engine. It is started either manually, with a timer (mounted on the
center console or in the glove box) or via a powerful FM-wireless
remote (the Mercedes units for from about 500 to 1000 meters
depending on local circumstances. The latest versions are available
with mobile phone remote control as well.

Once it is started, a spark plug ignites the burner which heats the
coolant up and the water pump recirculates the water through the
engine. The system heats the coolant up to 80°C and works until that
temperature is held in circulation. Once the temperature of 55°C is
achieved, a separate relay starts the heater blower and this heats up
the interior.

Even at very low temperatures in Alpine or Siberian regions, this
heats up the engine and the interior within 20-30 minutes. Apart from
a warm seat when you step in, the heat melts all snow and ice on the
windows without further ado.

Very comfortable and a must in Southern Germany, Switzerland and
Austria.

Many German Taxis have it as well since it helps them keep warm in
Winter when the wait and have no engine running.'

I still need some info to get mine working as well as instructions so if this rings a bell with anyone I'd love to know.
Thanks

Toby.

This is what the heater control looks like in the cabin.

Does the system heat the entire coolant of the engine, or just the contents of the heater core? That is, to help starting in extreme weather?

The same device has been employed by many manufacturers in the days of manual-choke carburettors - both to help starting and to heat the inside of the cabin. Russian Army and civilian-utilitarian vehicles have it as standard - on ZIL-131 trucks(6.5 litres V8 gasoline engines) it heats both the coolant and oil.

Some air-cooled vehicles and most large 18-wheeler trucks use a similar device which blows hot air instead of coolant, to heat the cabin.

Caution: if you are unsure of the device, have it checked by an experienced electrician!!! It can pose a MAJOR fire hazard if it malfunctions.

~Regards,

Nautilus

I have had contact from webasto who supplied the heater to MB and have subsequently obtained some pdf's of the operating instructions as well as a full manual for servicing and troubleshooting.

I hope this will enable me to get my heater working and contact me if you wish me to email the pdf's to you.

Thanks

There is a guy named SunMan on Mbworld forums that has installed the factory version on his W203 C320 Sedan. He stated it actually has a fuel line that connects to the fuel system and then a little gas or diesel heater that heats the coolant lines. It also has a little pump to circulate the warmed fluid. After 20 minutes I think it also turns on the fan in the HVAC system as well to warm the inside of the vehicle. Set up is in the Multi-Function Display on the dash and set with the steering wheel controls. You can set certain times of the day for this to operate as well as use a remote control to activate as well. This guy also has distronic, parktronic, folding mirrors, triple trunk locks and a few other goodies from the Euro models on his US model car. He has stuff that is not even normally offered on a C Class. Currently working on installing Active Heated/Ventilated Seats from a CLK as well.