Heating and Air Conditioning: Description and Operation

Vacuum System

Vacuum is supplied to four vacuum solenoids by a vacuum reservoir located under the battery. A non return valve prevents vacuum "bleed off".

The defrost/demist flaps are controlled by a defrost solenoid and are held closed by vacuum. The defrost solenoid valve is supplied by a green vacuum line.

The recirculation/fresh air flaps are controlled by the recirculation solenoid valve, and are held closed by vacuum. The recirculation solenoid valve is supplied by a white vacuum line.

The center vent is solenoid operated, opened by vacuum, and supplied by a black vacuum line.

The water valve is controlled by the coolant solenoid. The coolant solenoid valve is closed by vacuum and is supplied by a white vacuum line.

NOTE: Vacuum supply to the center vent and the recirculation flaps have built in restrictors to prevent system "hunting". The recirculation flaps can take up to 30 seconds to change state.