How To Flush Refrigerant Lines Using EnSolv® NEXT Solvent

Environmental concerns are a driving factor in industry these days, resulting in phase-outs as older materials and systems are replaced with ones that are more environmentally benign. In line with this trend, the refrigerant R-22, which itself was an improvement over earlier refrigerants, is currently being phased out and replaced with R-410a and other alternatives.

Unfortunately, retrofitting refrigeration systems to accommodate the new refrigerants is easier said than done. The refrigerants are not cross-compatible, so it’s necessary to completely remove all traces of R-22 from the system—including refrigerant lines.

In most cases, it’s best simply to replace old lines with new ones. However, it’s not always possible to do this cost-effectively, especially when the old linesets run under floors or through walls. In such cases, flushing refrigerant lines thoroughly is very important because even tiny traces of impurities left in the lines can damage new equipment and lead to compressor failure.

Why EnSolv® NEXT Solvent Is Ideal for Flushing Refrigerant Lines

The first step to proper lineset flushing is to select the right solvent. It’s imperative that the solvent you choose be highly effective at dissolving oil and contaminants, to ensure that all residue gets removed from the line. But it also should be as environmentally friendly as possible.

EnSolv® NEXT is an ideal solvent solution that offers a number of advantages as a refrigerant flushing solvent, including:

  • Non-flammable.
  • High solvency strength. With a KB value of 91, EnSolv® NEXT is a powerful cleaning agent that can flush lines fast.
  • Fast evaporating. It’s essential for all solvent to leave the lines after flushing; EnSolv® NEXT’s vaporizing ability allows it to evaporate away easily.
  • Environmentally responsible. EnSolv® NEXT solvent is SNAP approved, with low global warming potential, zero ozone depleting potential (ODP), and contains no hazardous air pollutants (HAPs).

How to Properly Flush Refrigerant Lines With EnSolv® NEXT

Once you’ve selected your solvent, you’ll need to conduct the flush in the proper sequence. Here’s how:

  1. Remove any obstacles. Any equipment such as filters and expansion valves that might obstruct the line should be removed prior to the purge.
  2. Do a nitrogen pre-flush. This will pull away any loose debris from the sides of the lines so the solvent can more easily do its work. 120 psi is recommended. It’s also good practice to oscillate the pressure to encourage dislodging of debris.
  3. Prepare the lines. You may need to cut longer lines into shorter segments for more effective flushing; 50-foot segments work well. You’ll also need to find a fitting for the inlet — you can braze on a ¼-inch brass flare fitting or hold a conical rubber fitting in place during flushing. Finally, crimp the exterior end of the lineset to encourage higher pressure in the line.
  4. Conduct the flush. In most cases, you’ll want to flush from interior to exterior to minimize fumes. Be sure to use a tarp or other method to protect areas where a solvent spill is a possibility. Collect used flushing liquid at the end of the line in a bucket or other solvent-proof receptacle. Flush until the liquid comes out clear; it’s a good idea to replace the bucket with a clean one near the end of the process so you can tell whether the solvent is running clear.
  5. Do a nitrogen post-flush. Do this immediately (within 10-15 minutes) after flushing, before the solvent has a chance to thoroughly evaporate.
  6. Clean up. Be sure to follow proper procedure for environmentally responsible disposal of waste solvent.

Of course, simply replacing old linesets is the only way to be 100 percent sure that your lines are clean. But in retrofit situations where complete replacement is not possible, flushing the lines with EnSolv® NEXT solvent is the best alternative solution. Try it for the protection and long working life of your refrigeration system upgrade.