The suction line of a refrigeration system is normally insulated with a flexible, closed-cell elastomeric material. Wall thicknesses vary between 3/8- and 1-inch. Medium-temperature systems generally require ½- to ¾-inch insulation. Low-temperature systems generally require ¾- to 1-inch insulation.

What happens if the suction line is not insulated?

Q: What happens if the suction line of an air conditioner is not insulated? A: It sweats, drips and adds more heat needing to be rejected by the condenser. Suction gas becomes hot and compression load increases. This increases compressor power consumption.

What are two common reasons the suction line is insulated?





1. It prevents the suction line from sweating and dripping water inside the house. 2. The insulation also prevents the suction line attracting heat from the outdoors on its way to the condenser coil.

Is the liquid or suction line insulated?

Liquid lines generally are insulated. They are warm to hot (110°F (43.3°C) for air-cooled). If liquid lines pass through a space that is warmer than the refrigerant (i.e. the roof of a building at roof level), or if they could be considered hot enough to pose a safety risk, then insulation should be added.

Where is the suction line on an air conditioning or refrigeration system is insulated to?

If you have an air conditioner, you have a suction line–that’s the “cold” copper line that runs between the compressor and the evaporator, and it carries the cool refrigerant back to the compressor to be turned back into liquid. When your HVAC system is new, this line is insulated air-tight with 3/4″ insulation.

How important is insulation on the suction line?

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.

Does the suction line need to be insulated?





This is called the “suction” pipe and is typically the larger of the two pipes. There is no need to insulate the smaller, warmer copper pipe, often called the liquid line, because not insulating this line allows it to shed heat which is exactly what you are trying to do with an AC system.

Which refrigerant line is insulated?

suction line

Refrigerant Lines



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.

Why must liquid refrigerant not enter the suction line?

Do not add refrigerant in this situation because you will overcharge the system. The overcharge will be noticed at the higher heat loads. The low heat loads cause the system to be at its lowest suction pressure, thus the density of refrigerant vapors entering the compressor will be lowest.

What problems are 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.

How do you insulate AC suction lines?

Quote from the video:
But as you can see it's got some tear strips that protect the glue. So you just fit it over the pipe you kind of dry fit it to start.

How do you identify a suction line?

Quote from the video:
Short it's so this they have names for the long lines one is called the suction line one. It's called the liquid.

What is the difference between suction line and discharge line?



The suction line connects the evaporator to the compressor, the discharge line connects the compressor to the condenser, and the liquid line connects the condenser to the expansion device.

What temperature is suction line?

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.

Which pipe is bigger suction or discharge?

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.

How cold should suction line be?

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 isn’t cold, or the liquid line isn’t warm, servicing should be recommended.

What should my suction line temp be R-22?



Low-Side Input or Suction Line Pressure in Air Compressor Conditioner: For low-side output pressure, using R22 pressure at 85 degrees is called for 45 degrees of the same compressor model. In case of using R22 inside, or at the ambient room temperature, subtract 45 degrees from the incoming air temperature.

What should the temperature difference be between suction line and liquid line?

Quote from the video:
But you're generally not gonna see more than maybe a two three degree difference in your liquid.

What causes high suction temperature?

High suction superheat—common system conditions that cause increased suction temperatures are high thermostatic expansion valve superheat settings, ineffective or missing insulation and restricted thermostatic expansion valves.

Should suction lines be hot?

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.

What does high suction temperature mean?



For a high-pressure suction to occur you could have an insufficient compressor. Meaning your refrigeration has a leaking discharge valve. … Without a needed refrigerant, it produces a higher temperature and pressure at the outlet of the evaporator, which causes a high suction pressure.