Steven Hockstein Posted June 27, 2009 Report Share Posted June 27, 2009 I inspected a house this past week and the air conditioning compressor is located in the rear yard. The electrical supply and the refrigerant lines are buried in the ground. The furnace is in a utility closet that is accessed from an exterior door at the rear of the house. Refrigerant pipe issues: Is it OK to bury the refrigerant lines and is the standard insulation wrap acceptable when buried. If not, what has to be done? Electrical issue: The compressor is about 25 feet from the house and the electric shut-off is on the house, not on the enclosure adjacent to the A/C compressor. Is this allowed (the shut-off can be seen from the compressor). Opinions please? Quote Link to comment Share on other sites More sharing options...
Jim Katen Posted June 27, 2009 Report Share Posted June 27, 2009 I inspected a house this past week and the air conditioning compressor is located in the rear yard. The electrical supply and the refrigerant lines are buried in the ground. The furnace is in a utility closet that is accessed from an exterior door at the rear of the house. Refrigerant pipe issues: Is it OK to bury the refrigerant lines and is the standard insulation wrap acceptable when buried. If not, what has to be done? I've seen it done that way several times and I've never considered it to be a problem. I'm not aware of any rule against it. Electrical issue: The compressor is about 25 feet from the house and the electric shut-off is on the house, not on the enclosure adjacent to the A/C compressor. Is this allowed (the shut-off can be seen from the compressor). Opinions please? If the disconnect is within sight and within 50' of the compressor, it's fine. - Jim Katen, Oregon Quote Link to comment Share on other sites More sharing options...
John Dirks Jr Posted June 28, 2009 Report Share Posted June 28, 2009 So it's ok for the high pressure(hot) line to be burried in the cool ground? Could this have a bad effect? Quote Link to comment Share on other sites More sharing options...
Steven Hockstein Posted June 28, 2009 Author Report Share Posted June 28, 2009 I inspected a house this past week and the air conditioning compressor is located in the rear yard. The electrical supply and the refrigerant lines are buried in the ground. The furnace is in a utility closet that is accessed from an exterior door at the rear of the house. Refrigerant pipe issues: Is it OK to bury the refrigerant lines and is the standard insulation wrap acceptable when buried. If not, what has to be done? I've seen it done that way several times and I've never considered it to be a problem. I'm not aware of any rule against it. Electrical issue: The compressor is about 25 feet from the house and the electric shut-off is on the house, not on the enclosure adjacent to the A/C compressor. Is this allowed (the shut-off can be seen from the compressor). Opinions please? If the disconnect is within sight and within 50' of the compressor, it's fine. - Jim Katen, Oregon Thanks. I have never seen a system installed this way. I felt it was OK but was not sure. Quote Link to comment Share on other sites More sharing options...
inspector57 Posted June 28, 2009 Report Share Posted June 28, 2009 So it's ok for the high pressure(hot) line to be burried in the cool ground? Could this have a bad effect? Perfectly fine, in fact you could pick up a little subcooling if the ground is below the air temperature. A heat pump would need both lines insulated. A few years ago, I researched a HP that had the ground source copper coil buried. I don't know if the system is still around though. If copper water lines can be buried, I don't see any problem. Quote Link to comment Share on other sites More sharing options...
Jim Katen Posted June 28, 2009 Report Share Posted June 28, 2009 So it's ok for the high pressure(hot) line to be burried in the cool ground? Could this have a bad effect? No. Better to be in the 55-degree ground than in 80-, 90-, or 100-degree air. - Jim Katen, Oregon Quote Link to comment Share on other sites More sharing options...
Thor Posted June 28, 2009 Report Share Posted June 28, 2009 Here is Trane's opion on underground linesets. Underground refrigerant line sets Stay away from under ground refrigerant line sets when possible. This design will create two situations: The worldââ¬â¢s longest oil trap A vapor line that acts as a liquid receiver Liquid refrigerant will always migrate to the coldest spot in a system; this will likely be the line sets under ground. A vapor line full of liquid refrigerant will slug the compressor on start upââ¬âespecially during long off cycles. The addition of a liquid line solenoid valve (cooling only units) will reduce the migration of liquid refrigerant and help save the life of the compressor. Quote Link to comment Share on other sites More sharing options...
Bill Kibbel Posted June 28, 2009 Report Share Posted June 28, 2009 I've discussed this with a few manufacturers many, many years ago. One response was: "No more than 36â⬠Quote Link to comment Share on other sites More sharing options...
Terence McCann Posted June 28, 2009 Report Share Posted June 28, 2009 Here is Trane's opion on underground linesets. Underground refrigerant line sets Stay away from under ground refrigerant line sets when possible. This design will create two situations: The worldââ¬â¢s longest oil trap A vapor line that acts as a liquid receiver Liquid refrigerant will always migrate to the coldest spot in a system; this will likely be the line sets under ground. A vapor line full of liquid refrigerant will slug the compressor on start upââ¬âespecially during long off cycles. The addition of a liquid line solenoid valve (cooling only units) will reduce the migration of liquid refrigerant and help save the life of the compressor. When line sets are buried they are typically close to the surface, not five feet down (who in the hell goes through all that work?) A liquid line solenoid valve will only help the condition when the unit has a pump down cycle - something that 99% of residential units do not have. A suction line accumulator will help prevent a slug of liquid coming back to the compressor - another option that most residential units do not have (my EMI ductless split system has one though). As far as the world longest oil trap goes I would be doubtful of that. Is the condensing unit 200 feet from the home? While oil does migrate through out the system more likely is a liquid slug than a pocket of oil (that is unless the evaporator is located stories above or below the condensing unit). Should the client freak out and demand that the line set be dug up and run along the surface - no. We typically have bigger fish to fry. Quote Link to comment Share on other sites More sharing options...
Thor Posted June 29, 2009 Report Share Posted June 29, 2009 Here is some good info for you. Download Attachment: CompressorRefrigerantflooding.pdf 330.06 KB Quote Link to comment Share on other sites More sharing options...
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