For a hermetic or semi-hermetic unit, checking for and removing acid is probably the most important maintenance check!

The operating life of refrigerators, heat pumps, and air conditioners are severely shortened by acid levels as low as 50 parts per million of acid! These acids can be formed by chemical reactions with components and/or materials of construction, lubricating oils, and/or impurities. The instability of the refrigerant, and thus the formation of acids is accelerated by elevated temperatures which could be the result of improper operation, such as a failed condenser fan, a clogged air flow path, or an improper refrigerant change-over. Acid formation can also be the result of oil and/or refrigerant incompatibilities, such as mineral oil/POE oil incompatibilities, refrigerant/gasket material incompatibility (Viton/R-134a), low thermal stability of the HFC refrigerant/oil mixtures, or extended operation off the design point.

Checking the refrigerant and/or oil acid is a common maintenance recommendation since acidic conditions can be cleaned up before a compressor motor burns out. With the new HFC refrigerants, the various types of oils that could be in a system, and the recycling of refrigerant it is more important than ever to check the acid in a system. You can check for acid with any one of oil test kits on the market, I recommend the Mainstream http://www.qwik.com/q_qwikcheck.html QwikCheck 5-second acid test because it is accurate, fast, and inexpensive. It will detect acid levels before they get to a harmful concentration, it works with all refrigerants and oils, and will not give a false reading when used with Ester-based oils. (The ability to be used with any oil is critical because you may not even accurately know the type of oil in a system!) Many oil acid test kits give a false acid reading with ester-based POE oils because the chemistry of the oil behaves like an acid to the test kit (The fancy name for this is Amphoteric properties).

A really convenient thing about the QwikCheck, is that for Hermetic Compressors it is very difficult to get some oil out for a oil acid test so what happens ... you probably never perform an acid test.... but these hermetic units are also the most sensitive to acid burn-outs! With QwikCheck, you hold the QwikCheck on the compressor service valve and 5-second later you have the results.

If acid is detected, use Mainstream's QwikShot Acid Flush (http://www.qwik.com/q_qwikshot.html) coupled with a filter/drier change to get rid of the acid BEFORE THIS ACID CAUSES THE SYSTEM TO BURN OUT.

QwikShot is not just for burn-outs, it is also for preventative maintenance! For a few bucks and a few minutes of your time you have probably saved that compressor and that's the key to preventative maintenance.

The QwikShot leaves no residue in the system, and it is compatible with all oils and refrigerants so it is quick, inexpensive, and easy to use. This patented Acid Flush is only available in the Mainstream QwikShot. Another somewhat common BUT UNACCEPTABLE approach is to neutralizing this acid by reacting it with a base (the base which is typically a solid is dissolved in an alcohol solution) but this results in the formation of undesirable and corrosive salts and moisture in the system. While the filter dryer will remove the moisture, the corrosive salt is there forever!

Another serious problem with the acid-base neutralization approach is that the base is also a solid caustic compound, which if un-reacted in the system can cause as much damage as the acid itself and the proper quantity of base to add, to properly neutralize the acid, is difficult to determine in the field, since the exact acid level is probably not known.

Don't trade one problem, namely acid, for another problem, namely corrosive salts or a corrosive solid base residue!

The QwikShot Acid Flush is absorbed into the drier along with the acid or moisture, leaving no residue of any kind that could invalidate a warrantee. The QwikShot will also accelerate the movement of moisture into the filter-drier. The QwikShot Acid Flush dose uses only a fraction of the capacity of the filter-drier. If you are concerned, when you replace the filter-drier use a larger one (Approximately 25% larger if molecular sieve drier, 50% larger if an activated alumna drier).

Some people have been concerned about the need to change the filter-drier when acid is detected. This is completely wrong! Every compressor manufacturer recommends changing the filter-drier when acid is detected. It is a critical step, whether or not you use any acid treatment. The filter-drier must be changed or there is nothing in the system to stop future acid accumulation. The use of QwikShot is the second step, since it accelerates the transport, of the acid in the system, into the filter-drier. This accelerated removal of acid is needed, because if acid is detected either: the filter-drier capacity is exhausted or the acid is being generated faster than the filter-drier can remove it. Our test results (see http://www.qwik.com/qwik-art2.jsp ) have shown that once a significant amount of acid has been accumulated, if you only change the filter-drier, the acid level is so high it will most likely burn out the compressor before the filter-drier has a chance to get all the acid out. With QwikShot Acid Flush, the transport of the acid is dramatically accelerated.

The QwikShot dose was calculated to take up half of the capacity (by mass) of an activated alumna drier. It will actually take up significantly less of the capacity of a molecular sieve drier since they hold much more moisture or acid per unit volume.

The QwikShot Acid Flush, moisture and acid are all physically absorbed into the drier and can not be released with vibration, jarring or moderate temperatures. It would take a temperature above about 900 C (1625 F), and reduced pressure (vacuum) held for several hours for the acid, moisture or QwikShot to be released. Clearly, they will not be released during operation.

Excess QwikShot Acid Flush does not hurt the system in any way, since it is also adsorbed into the filter drier. If there is no more acid to be removed from the system the QwikShot Acid Flush will attract the excess water molecules next, and facilitate their transport into the drier. The QwikShot Acid Flush does not in anyway affect the performance of the filter/drier. It does use some of the capacity of the drier, but since the drier is being changed this is not a problem. We do not even suggest using a larger drier, however, if desired you can use a 25% larger (by volume) drier if a molecular sieve drier is being replace and a 50% larger drier if an activated alumna drier is being replaced with another activated alumna drier. If an activated alumna drier is being replaced with a molecular sieve drier the capacity has already been increased substantially (by the improved adsorption capacity of the molecular sieve), and no increase in volume is recommended.

You must change the drier if there is a burn out. If you are going to do only one thing then change the drier. This must always be done on a burn out. Every compressor manufacturer specifies this and suggests you add a suction line drier to catch any residual acid in the lines (and keep this acid from reaching the compressor). We agree completely! So QwikShot Acid Flush should always be used with a new drier.

If you dont have a burn out, but you detect acid, you again must change the drier. Some acid neutralization companies, (but no compressor manufacturers) might tell you just neutralize the acid, you dont need to change the filter/drier WRONG. Ask any compressor manufacturer, they will all tell you that you must change the filter/drier!

Again, if you do nothing else, change the drier, it is the most critical item! If you simply neutralize the acid that is present and dont change the drier, the acid and moisture levels can and will shoot right back up again, because you have left no back-up or residual protection. Neutralizing the acid only treats the system at the time it is added. Excess neutralizer reacts with the materials of construction (a potential problem) and is depleted (converted to a caustic salt); it does not remain active in the system to treat future acid. Only the drier remains in the system to remove acid and water as it appears. The problem with a high acid level is that the compressor will burn out, before the acid can be removed by the drier. QwikShot Acid Flush accelerates the transport of acid to the drier, so that it can be removed faster.

Without a drier change, there is no capacity to maintain a low acid level. If you are not changing the drier, you are wasting your time, no matter what type of acid treatment you are using. Changing the filter/drier must always be performed, it is the most critical component of proper acid treatment!

You can check the oil for acid (with any one of oil test kits on the market), or you can check the refrigerant for the acid using Mainstream's QwikCheck.

I strongly recommend the Mainstream QwikCheck 5-second acid test of the refrigerant because it is accurate, fast and inexpensive. It will detect acid levels before they get to a harmful concentration. It works with all refrigerants regardless of the oil used, and will not give a false reading when used with Ester-based oils, such as POE oil.

The ability to produce accurate readings with any oil is critical because you may not know the type of oil in a system! Many oil acid test kits give a false acid reading with ester-based POE oils because the chemistry of the oil behaves like an acid to the test kit, that is the ester oil displays amphoteric properties.

When a compressor burns out, the oil becomes extremely acidic and if all this acid is not removed when the compressor is replaced, the elevated acid levels will attack the new compressor and cause another compressor motor burn-out. Premature compressor burnout after a prior burnout is quite common, because of residual acid. Acid cleanup normally involves changing the compressor oil and the refrigerant to reduce the acid level (and changing the hermetic or semi-hermetic compressor if it did burn out). Unfortunately however, removal of the oil, contained in the compressor, does not remove all the oil or acid in the system since acid is carried throughout the vapor-compression loop by the flowing refrigerant and therefore acidic oil or its residue is throughout the system. (This residual acid has been shown to shorten the life of the system since this residual acid will lead to accelerated acid formation in the system. This has been supported by experimental evidence in the literature that after a burnout the frequency of subsequent burnouts increases.

Depending of the refrigerant and oil being used in the system two types of acids, organic acids (such as oleic acid), which are soluble in the oil (and do not vaporize) and therefore stay predominately in the liquid oil in the compressor oil sump and inorganic (mineral) acids (such as hydrochloric acid), which are only slightly soluble in the oil. The organic acids are significantly less corrosive and only found in ester based oil or in systems where a strong oxidizer and high temperatures are present.

Therefore, organic acids are rarely if ever found in today's systems in any appreciable concentration. Both inorganic and organic acids are corrosive. However, inorganic acids have higher dissociation constants, especially hydrochloric acid, making them strong and very reactive acids, while organic acids react much slower.

In the case of mineral oils, elevated temperature causes the oil to ultimately break down and the ultimate products are carbon and hydrogen gas. Only in the presence of an oxidizer, such as oxygen or air, can organic acids be formed.

In the case of synthetic ester (POE) oils, organic acid may be initially present (up to 8 PPM) as a residual from the esterification manufacturing process used to make the ester oil.

It is clear that the real acid problem in refrigeration/air conditioning systems is an inorganic acid problem not an organic acid. During a compressor-motor burnout, inorganic acids are formed as a result of the refrigerant decomposition at elevated temperatures. A significant portion of the inorganic acids generated during a motor burnout remains in the vapor phase and reacts quickly with the materials of construction or is adsorbed in the filter/dryer. However experiments have also shown that an appreciable quantity of inorganic acid is also contained in the oil and the concentration of acid trapped in the oil is higher than the quantity which would be simply dissolved in the oil, because the solubility for inorganic acids is relatively low. This acid concentration is a combination of acid dissolved in the oil, acid trapped in the oil (due to the oil's foaming and agitation), acid dissolved in any trapped moisture, and acid adsorbed onto the hard particles present in the oil.

This inorganic acid has been shown to remain in the oil for an extremely long time and this acid is in contact with the compressor components, including the motor windings. The inorganic acid in the oil will etch the lacquer insulation from the wire causing the motor winding to short out electrically and resulting in a subsequent motor burnout.

Above an acid concentration of 50-PPM the compressor motor has been found to burnout in a matter of days.

The best way of removing the acid is to flush it or free it from the liquid and hard surfaces that contain the acid using QwikShot™ Acid Flush, and let the filter-drier in the system remove the acid.

A filter-drier does an excellent job of removing acid, the problem is that normally the acid that is trapped on the hard surfaces and in the oil and therefore the acid never effectively gets to the filter-drier.

Another good, but very expensive approach to remove the acidic residue throughout the system is by performing several flushes of the vapor-compression system with refrigerant, since refrigerant will dissolve the oil and reduce the oil and acid concentrations by dilution. However, because of EPA mandated refrigerant recovery requirements, this is a costly and time consuming task and the cost of the refrigerant used in the flushing operation is not trivial.

The worst way is to attempt to neutralize the acid by reacting the acid with a basic solution (a solid base dissolved in a liquid carrier). This will always result in the formation of undesirable salts. In such a neutralization reaction, the acid and base combine to form a metallic caustic salt and water. While the water can be removed by the filter/dryer in the system, the salt remains lodged in the system and could cause problems. Since the salt is a solid it will not vaporize, but instead will remain in the compressor's crankcase. Also to properly neutralize the acid the proper amount of base must be added, too little base and the refrigerant is still acidic, too much base and the refrigerant is basic. An acidic or basic environment will cause corrosion and premature compressor life (burn-out).

The advantage to the patented QwikShot Acid Flush approach of liberating the acid is that since there is no neutralization reaction there is no formation of a caustic salt residue. This innovative technology to provide this acid flushing action is patented and is only available in the QwikShot™ Acid Flush . The other benefit of the use of QwikShot is that not only is the acid picked up and removed from the system by the filter-drier, the QwikShot is also picked-up and adsorbed by the filter-drier thereby leaving no residue at all in the system!

It is generally accepted that adherence to Standard 15 of the American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE) will ensure the safety of technicians and building occupants. This standard applies to the use of all alternative refrigerants. In addition, systems designed and operated in accordance with ASHRAE Guideline 3 will leak minimal amounts of refrigerant, thereby reducing ozone depletion and global warming impacts.

The max amps for our QwikLugs are as follows: