AC line Insulation

[Bulldog13]

Stupid question I’m sure but ….this is my new Trane 3ton AC.There is insulation on some of the lines but this copper line is uninsulated.Should I cover the lines? My buddy said he painted his to protect it from the elements .

 

[aggie113]

Traditional compressor then only one line is cold. The uninsulated line is carrying hot refrigerant and it won't have an issue with condensation or needing to keep cold in. If it was a heatpump then both should be insulated as they can swap rolls.

 

[Bulldog13]

Traditional compressor then only one line is cold. The uninsulated line is carrying hot refrigerant and it won't have an issue with condensation or needing to keep cold in. If it was a heatpump then both should be insulated as they can swap rolls.

Thanks….I appreciate the info

 

[bonneyman]

Traditional compressor then only one line is cold. The uninsulated line is carrying hot refrigerant and it won't have an issue with condensation or needing to keep cold in. If it was a heatpump then both should be insulated as they can swap rolls.

This is not entirely accurate.
With heat pumps, the freon flow is reversible - but the small line is always the liquid line. Typically in cool mode it loses heat on it's way to the evaporator (logic dictates one should leave it uninsulated so the liquid freon can lose heat on it's way) but - if it travels thru a hot attic - it might actually GAIN heat, causing several issues. One's particular situation should dictate whether it should be insulated or not.
In heat mode the small line is still carrying liquid - just in the opposite direction. It may lose or gain heat during it's travel (again, depending on the individual installation) but if it's insulated, it won't lose heat to the surrounding environment in cold weather. And that will keep the heat in the freon to be recycled into the home on the next trip. If it's not insulated the loss might not be huge but - in heat mode - every BTU of retained heat adds to the heating efficiency. So better to insulate it.

The main thing is both lines (whether insulated or not) should be separated and not run together in the same tube of insulation.

 

[fitter30]

No need to paint any copper line. Mini splits have both lines insulated because there is a expansion device in the outdoor unit both lines get cold and sweat.

 

[aggie113]

This is not entirely accurate.

Well, I stand by my Signature, if not my post.

 

[tinmanwpk]

The rubber insulation should be painted to preserve it from UV. Simple leftover latex paint will work just fine.

 

[Dumber than lumber]

The rubber insulation should be painted to preserve it from UV. Simple leftover latex paint will work just fine.

My AC company used white mastic on the rubber foam insulation. They said it will make it last longer and stay cooler. Something about the color black and sunlight makes heat gain significant . LOL