What Is a Suction Hose in an A/C System?

by Steve Hamilton

Air conditioning (A/C) systems consist of three main components: the compressor, evaporator and condenser. Running between these components are lines carrying refrigerant in various states. The suction line is referred to as a hose mainly in automotive systems where it is usually made of a special rubber rather than metal tubing. The suction hose can also be identified by certain other characteristics.

Temperature

The suction hose is the cold line. Since it carries refrigerant to the compressor from the evaporator, it is lower in temperature than any line in the A/C system except those inside the evaporator itself.

Pressure

The suction hose is the low pressure line. When it enters the evaporator, the refrigerant goes from a high pressure liquid to a low pressure vapor. This condition continues until it returns to the suction side of the compressor. Hence the name, suction hose.

Size

The suction hose is the large line. In most A/C systems, especially those in automobiles, the suction hose is considerably larger than the other A/C lines. It is carrying refrigerant vapor and lubricant which must have room to flow with minimal resistance.

References

About the Author

Steve Hamilton has been writing professionally since 1983. His credits include novels under the Dell imprint and for Harlequin Worldwide. A remodeling and repair specialist with over 20 years experience, he is also a Certified Pool Operator and holds an EPA Universal refrigerant certification.

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