At this point we'll one again remind you of the variations:
There are two types of coolant heating. Firstly, there is the heating which is basically, always built in by the manufacturers. Thus, it belongs to the vehicle- heating and is laid out accordingly. As a rule it is not specially activated, but is supplied by the system according to the heating requirements.

The second heating which acts on the coolant, is the stationary heating. It can either be standard equipment or can be installed later on. In the latter case, access to vehicle's blower-fan must also be possible, for the heat to be directed into the interior of the vehicle. The stationary heating can heat the engine and the interior at the same time, or, fitted with the respective valves, only heat the interior. It may also be possible, that only the engine can be heated.

Only the stationary heating has a separate control. The equipment can be started immediately from the outside, by pressing the 'heat' button on the remote control. The automatic switching off when a certain interior temperatur has been reached, is generally only possible if the equipment is completely integrated (stardard) into the vehicle. Otherwise, the heating time has to be set and can generally, not be longer than one hour. During he heating period the fresh-air fan blows air through heat exchanger of the heating system.

Apart from the control device and the actual heater, the stationary heating also has a fuel pump, a coolant pump (shown in green at the top) and one or more valves in the coolant-/ or heating circulation. The fuel pump transports only a small amount per electrical impulse, that means it is continuously being triggered, which has a dosaging effect. It does not have a circulatory, but a spring loaded displacement pump.

Thus the fuel reaches the narrowest point of the venturi, air is pumped in through a pump (in blue on the left) which is integrated into the heating device. At this point, two electric components are particularly important: The glow-plug for the additional initial accompanyment, giving a stable combustion, which, together with a temperature sensor can cause the complete shut-down of the system in the event of it's overheating.

Only now can a difference between the hardware for a Diesel- and for a petrol operation be recognised. Obviously, when running on Diesel fuel, the warming of the fuel and an additional shut-off valve is necessary. In newer variations, the fuel evaporates through a metal-fleece, thus burning more evenly. According to the manufacturers, this does not lead to a consumption reduction.

Buying the equipment is the most expensive factor of stationary heating anyway. Even when operating for one hour under full strain, according to the manufacturers, only 0,67 liters of petrol or 0,59 liters of Diesel will be used. During a severe winter, this could mean, for taxi drivers who leave the engine running at the rank, an improvement as far as economy and ecology is concerned. This goes to show, just how enormous the amount of energy contained in the fuel is.

It warms up because coolant is pumped into the ribbed cavities around the combustion chamber (on the right shown in red), then transported to the heat exchanger of the heating. On the outside, the stationary heating can now almost be touched by hand. This, at least, is suggested by the external plastic covering. This heating can be installed anywhere in the car where enough space is, if needs be, even in the interior. The necessary installation space is increased through the inlet- and exhaust dampers (shown in red at the bottom). 09/13