ACR Journal

June 2022 | July 2022 22 Volume 8 No.4 to accelerate, ultimately resulting in a compressor burnout. Engineers are encouraged to perform acid checks regularly. This is where a sample of the system oil is removed and tested for traces of acids. If acids are present, then this needs to be addressed immediately, as to maintain oil stability and system health. The reverse reaction may be slow at first, then as equilibrium is achieved, the reverse reaction accelerates considerably. This is like starting at the top of the slide, as you proceed down the slide your speed increases, until you hit the bottom and fly o . Effect of moisture on an HVAC system. We have already discussed what impact moisture has on POE lubricants, by driving a reverse reaction of the ester product, forming acids via hydrolysis. Moisture has even more detrimental e ects on a HVAC system, which include: Corrosion – water is detrimental to compressor windings and pistons, creating rust. Ice crystals – system low-side, temperatures in and around freezing may form ice crystals which intern may cause blockages and or stick. Oxidise active metals such as copper. Water in its liquid state become trapped within system pipework. Moisture can permeate through plastic containers; for this reason producers ensure a moist-free environment and bottle this product in sealed metal cans. It is essential to ensure moisture levels are reduced, which may di cult to identify within a system, for this reason acid test kits are o ered to identify acid compounds instead of moisture molecules. Moisture will remain undetected, so to e ectively be able to identify whether the POE has hydrolysed, acids will be present and are detectable via an acid test kit. The solution: filter driers Filter driers, such as Dry All filter driers, are installed just in front of the thermal expansion valve on the liquid line. This is to ensure maximum liquid exposure throughout the drier, where the desiccants can absorb moisture and acids from the passing refrigerant. Filter driers are genuinely made from a steel or copper housing, with a desiccant core inside. Di erent sized driers are available to cater for all system types. Depending on the system type will determine what fitting is needed, whether solder (sweat-type drier), flare- or compression- fittings. Below is an example of a traditional filter drier. For larger systems, replaceable cores are available. Cores are the inside part of a drier, which can be changed without the need of the outer housing. A core shell (a permanently installed housing for the core), is installed onto the system, which can be isolated so the core can be replaced when necessary, see cores below: Perfect team We have discussed how a HVAC systems health is impacted by the stability of POE lubricant. We know it is vital to ensure moisture is removed to prevent hydrolysis and other corrosive properties. Testing for acid will indicate if a reverse reaction is occurring. The best safeguarding measure is to have installed and periodically replace the filter drier. These simple components are designed to absorb moisture and acid compounds, which maintains directly the health of the lubricant and therefore the health of the compressor. For more information contact your preferred wholesale partner. Proof is in the testing We have a limited number of FREE samples on o er across 032S, 032F, 053S, 053F and Replaceable Drier Types. To trial your FREE sample or schedule a FREE onsite consultation. Register by visiting: https:// www.dryall.co.uk In the next issue of ACR Journal, Part 2 of this article will explore how POEs are protected during the manufacturing process, introduction of additives and what makes for good filter drier selection. ester side of our scale’s analogy. As esters are formed during esterification, hydrolysis is the reversal of this reaction. POE lubricants are hydrolysed (broken down by reaction) by water. If we use a refrigeration system as an example, if water is present within the circulating refrigerant, then the reverse reaction may begin, be-it very slowly, without much noticeable impact on the systems performance. If moisture is present within the cycle, this will eventually begin to produce carboxylic acid compounds and alcohol, by reverse reactions as the POE lubricant is hydrolysed by water, see below: The catalyst in this case is the hydroxonium ion, H 3 O + , which is present in all solutions of acids in water. More acids that form accelerate the hydrolyses ff ct. In principle, hydrolysis beco es self-catalysing, driving the equilibrium back the other way, into the base compounds that from the ester product. The catalyst acid forms and if left unchecked/treated, then these smaller reactions will begin to accelerate, ultimately resulting in a compressor burnout. Engineers are encouraged to perform acid checks regularly. This is where a sample of the system oil is removed and tested for traces of acids. If acids are present, then this needs to be addressed immediately, as to maintain oil stability and system health. The reverse reaction may be slow at first, then as equilibrium is achieved, the reverse reaction accelerates considerably. This is like starting at the top of the slide, as you proceed down the slide your speed increases, until you hit the bottom and fly off. <subhead> Effect of moisture on an HVAC system. We have already discussed what impact moisture has on POE lubricants, by driving a reverse r the ester product, forming acids via hydrolysis. Moistur has ev n more detrimental effects on system, which include: 1. Corrosion – water is detriment l t c mpress r windings and pisto s, creating rust. 2. Ice crystals – system low-side, temperatures in and around fr ezing may form ice crys intern may cause blockages and or stick. 3. Oxidise active metals such as copper. 4. Water in its liquid state become trapped within system pipework. Moisture can permeate through plastic containers; for this reason producers ensure a moist-fr environment and bottle this product in sealed metal cans. It is essential to ensure moisture lev reduced, which may difficult to identify within a system, for this reason acid test kits are offer identify acid compoun s instead of moisture molecules. Moisture will remain undetected, so t effectively be able to identify whether the POE has hyd olysed, acids will be present and are d via an cid test kit. <subhead> The solution: filter driers Filter driers, such as Dry All filter driers, are installed just in front of the thermal expansion val liquid line. This is to ensure maximum liquid exposure throughout the drier, where the desicca absorb moisture and acids from the pa ssing refrigerant. Filter driers are genuinely made from a steel or copper housing, with a desiccant core inside. D sized driers are available to cater for all system types. Depending on the system type will deter fitting is needed, whether solder (sweat-type drier), flare- or compression- fittings. Below is an of a traditional filter drier. For larger systems, replaceable cores are available. Cores are the inside part of a drier, which c changed without the need of the outer housing. A core shell (a permanently installed housing SYSTEM LUBRICANTS