ADDITIONAL HEATER - Description

1.9 JTD 8v, 1.9 JTD 16v

Description

The climate control via the heater unit is insufficient when the engine is cold, especially in Diesel engines which are slow to warm up.

These engines may optionally be fitted with a supplementary heater system. This remains active from the moment when the engine is turned on until a certain temperature is reached.

The system consists of an additional heater, located in the heater unit: the device contains three resistances (PTC).

The operation of the resistances is controlled by a specific control unit - connected via the CAN network to the car's other nodes - which drives only one, or two or three, thus providing progressive heating.

This control logic depends on:

• the temperature of the engine coolant;
• the electrical power available (in effect, the battery voltage is checked)
• the engine speed (which should be above a pre-set value).

The supply of one, two or three resistances is controlled by two relays located on the heater unit:

• 1. Level: activated by the first relay;
• 2. Level: activated by the second relay;
• 3. Level: activated by both relays.

This supply is interrupted in the case of overtemperatures, via a specific safety switch.

Also, when the heater is on, the switching on of the fan is controlled See E6020 AIR CONDITIONING.

For more details Characteristic of working principle 5040 AIR CONDITIONING CASING AND COMPONENTS.

The supply line is protected by a specific maxifuse and a bridge fuse.

1.9 JTD 8v, 1.9 JTD 16v · Automatic Air Conditioning

Description

The climate control via the heater unit is insufficient when the engine is cold, especially in Diesel engines which are slow to warm up.

These engines may optionally be fitted with a supplementary heater system. This remains active from the moment when the engine is turned on until a certain temperature is reached.

The system consists of an additional heater, located in the heater unit: the device contains three resistances (PTC).

The operation of the resistances is controlled by the climate control unit which either operates only one, two or three of them, providing gradual heating, with a maximum power of 700 W following a logic which depends on:

• the temperature of the engine coolant (about 60°?);
• the engine speed (which should be above 700 rpm).
• the battery voltage (which should not go below 12.2 V).

For more details Characteristic of working principle 5040 AIR CONDITIONING CASING AND COMPONENTS.

The supply of one, two or three resistances is controlled by two relays located on the heater unit:

• 1. Level: activated by the first relay;
• 2. Level: activated by the second relay;
• 3. Level: activated by both relays.

The supply line is protected by a specific maxifuse and a bridge fuse.

1.9 JTD 8v, 1.9 JTD 16v · Webasto

Description

In cold weather the WEBASTO additonal heater heats up, maintains the temperature of and circulates the engine coolant for a pre-set time to ensure that the engine temperature and passenger compartment conditions are optimum when the engine is started up.

Completely independent of the operation of the engine, the additional heater makes it possible to:

• heat up the passenger compartment with the engine switched off;
• defrost the windows;
• heat the engine coolant and consequently the engine before starting.

The system consists of:

• a diesel burner for heating the engine coolant with an exhaust silencer for the combustion gases;
• a metering pump connected to the vehicle tank pipes to supply the burner;
• a control unit integrated in the passenger compartment heating/ventilation unit which allows automatic operation;
• an electronic control unit to control and adjust the burner incorporated in the burner itself;
• a relay for remote activation

After the heater has been activated, the electronic control unit operates the coolant circulation pump and switches on the burner through pre-set, controlled modes.

The circulation pump flow rate is also controlled by the electronic control unit to keep the initial heating time to a minimum.

The additional heater is switched on and off using a special remote control (this remote control has a maximum range of around 600 metres in open spaces, with the range reduced in built up areas. )

The signal issued by the remote control is received by a special aerial on the car and sent to the heater control unit.

The time the additional heater stays on is pre-set at thirty minutes after which the heater goes off (this period can be increased up to a maximum of sixty minutes; by pressing the two remote control buttons simultaneously three times in quick succession).

even though it is to a lesser extent, the heater burns fuel like the engine, therefore the additional heater should never be left on, not even for short spells, in closed areas where there are no exhaust gas extractors.

whilst the heater is working with the engine switched off, it absorbs energy from the battery; therefore it should be operated with the engine running to make sure that the battery is properly charged.

The system supply line is protected by a specific maxifuse and a bridge fuse.