The larger line typically carries a cool gas and is insulated. This is commonly referred to as the suction line, but it is also called the return line or vapor line. The smaller uninsulated line typically carries a warm liquid. It is most often called the liquid line.

Is suction line high or low side?

The low side, or suction line, will be the line connected to the compressor from the top or higher position. It will be cold to the touch and may be wrapped with insulation.

How do you identify a suction line?

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Why is suction line bigger?

The discharge pipe may be larger than the suction pipe. The purpose of the lines is to keep the losses to a minimum. This is done to make sure there is enough Net Positive Suction Head available to meet the requirements of the pump.

What happens if your suction line is too small?

If you decrease the suction line size the opposite happens, suction gas velocity increases and pressure drop increases. If you decrease the suction line size too much then you will restrict the mass flow resulting in low suction pressures/temperatures, as the compressor cannot overcome the increased resistance.

Why is the suction line insulated?

Insulating the suction line is done to prevent condensate from developing and dripping off. This condensate drip can cause water damage to the material under it or cause a slip hazard for people walking below it.

Which line is bigger liquid or suction?

The larger line typically carries a cool gas and is insulated. This is commonly referred to as the suction line, but it is also called the return line or vapor line. The smaller uninsulated line typically carries a warm liquid. It is most often called the liquid line.

What is the main problem caused by oversized suction lines?

Liquid lines that are too large cause one of two problems: overcharge or undercharge. Liquid lines rob refrigerant from the system. Any refrigerant that is in the liquid line is doing nothing for the cooling or heating process.

What size is suction line?

The larger pipe is known as the suction line, and includes insulation. The diameter on the liquid line for standard residential systems is 3/8 inches in diameter. The suction line diameter is normally either 3/4, 7/8 or 1 1/8 inches, it depends on the size (and efficiency) of the air conditioning system or heat pump.

Why is the suction line cold?

The Copper Pipe (Suction Line) should be sweating and cold to the touch during a hot day. If it is not cold, your compressor could be off (bad capacitor/ hard start kit) or low on Refrigerant. Your Breaker is Tripped. Be Careful because this usually indicates a problem with the compressor or wiring.

Why is the suction line not cold?

The Copper Pipe (Suction Line) should be sweating and cold to the touch during a hot day. If it is not cold, your compressor could be off (bad capacitor/ hard start kit) or low on Refrigerant. Be Careful because this usually indicates a problem with the compressor or wiring.

What happens if the suction line is not insulated?

If the return line is not insulated, the refrigerant returning from evaporator to the compressor will absorb some heat, more heat than it had at the outlet of the evaporator. This extra heat will also be present in the compressed refrigerant going to the condenser, downstream of the compressor.

Does line set size matter?

Among other things, an incorrectly sized line set can lead to premature compressor failures. Liquid lines must be large enough to minimize pressure drop, but small enough that the extra refrigerant they hold will not damage the compressor.

Why is the liquid line smaller than the suction line?

Re: Why are discharge lines smaller than suction lines? The mass flow is the same in the suction and discharge, in the suction you have low density, in the discharge you have higher density. In addition vapour in suction pipe has high density in discharge lower.

What temp should my suction line be?

The suction temperature should be above 35°F and below 65°F entering the compressor and the discharge line temperature should be below 220°F and above 150°F (typically) on a properly functioning package unit.

Should suction line always sweat?

The Copper Pipe (Suction Line) should be sweating and cold to the touch during a hot day. If it is not cold, your compressor could be off (bad capacitor/ hard start kit) or low on Refrigerant.

Why is my suction line sweating?

A sweating suction line is perfectly normal. Excessive sweating might be caused by not insulated well enough or too cold due to poor air flow over the evaporator. Some types of systems might sweat a lot because of being overcharged but in that case, usually the whole compressor will be sweating.

What should my suction line temp be R22?

For high-side output pressure, using R22 pressure at 85 degrees is called for 120 degrees. In case of using R22 inside, or at the ambient room temperature, add 35 degrees to the incoming air temperature. An output high-side compressor pressure of about 260 psi is used.

Should suction lines be hot?

Look for the suction line to be at roughly 45F to 55F, and the liquid line to be at about 90F to 110F. If the suction line isnt cold, or the liquid line isnt warm, servicing should be recommended.