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11.7 Hoses
Roles:
g
The A/C hoses route the fluid and connect the
loop components together.
g
Composition: a rigid part (aluminum or steel
tube), a flexible part (rubber hose), fittings and
seals, noise absorbers (mufflers), valves
The hoses are a mix of rigid and flexible tubing
g
Assembly is done via crimping
g
Aluminum parts allow weight reduction
g
Flexible tubing ensures vibration durability
g
Temperature range is from -40°C to +135°C
The hoses support additional features
g
Diagnostic and maintenance coupling systems
g
Pressure sensors
Seals
Roles:
Seals ensure the tightness of the A/C loop ;
they make an essential contribution to the longevity
of the system.
The O-ring is the most common type of seal.
Operation:
Seals acts in a number of different ways, depending
on the design of the sealing system: joints can be
sealed by contact, compression or crushing.
Seals are installed in every connection between each
components of the A/C loop (compressor, condenser,
receiver drier, expansion valve and evaporator) or the
various options that may be installed on the hoses
(pressure switches, valves, etc.).
The loop lubrication is key to system tightness;
O-Rings must be lubricated to be fully efficient
g
As O-Rings must be lubricated to properly, a long
period without activation of the A/C system can
generate fluid leakage.
11. The components
of the A/C Loop
56
Practical advice:
Recommendations on seals.
The O-ring must always be oiled before it
is installed, with the same oil as used in
the compressor, in order to make a per-
fect seal.
The O-ring is the most common type of seal.