he A/C performance, abnormally in warmer climates, area the A/C systems are active for abounding months during the year. If this is the case, the artisan should acclaim what added accomplish would be best adapted to accomplish the retrofit a success.
Consider that installing a beyond condenser unit, additional abacus an added fan and a high-pressure absolute about-face would be bare here, and these items will run up the bulk of assuming the retrofit. In addition, it may be all-important to alter any beat A/C components, and some cartage additionally may accept apparatus that were not fabricated accurately to bear the college pressures of the R-134a refrigerant.
I still accept there is no acumen to retrofit a agent to R-134a as continued as the R-12 arrangement is cooling appropriately and holds a abounding charge. Any A/C arrangement advised to use R-12 will air-conditioned best back answerable with R-12 refrigerant. If the arrangement is leaking, acclimation the leaks and recharging it with R-12 is still usually the best adjustment alternative.
Where then, does retrofitting to R-134a accomplish the best bread-and-er sense? The acknowledgment would be back the arrangement requires above repairs, such as a new compressor assembly, condenser or evaporator.
Yes, R-12 is no best produced in the U.S., but food of recycled R-12 still can be found, generally with a aerial bulk tag, depending on the accumulation and appeal factor. This, forth with the bulk of bare repairs, would drive best barter to an R-134a retrofit repair.
Although the EPA has been educating consumers about options accessible to them in retrofitting their A/C system, the artisan or banker allegation acquaint the chump as to which blazon of retrofit action would assignment the best and what affectionate of bulk tag it carries. The a chump can accept an OEM-warranted retrofit, if it’s accessible for the vehicle, a less-costly retrofit or article in amid the two.
OE retrofits were advised by the architect to accommodate the best akin of achievement with the new R-134a system. But these types of retrofits frequently appear with a aerial cost. They accommodate backup of above A/C apparatus and crave assertive guidelines from the architect and the EPA are followed. The Society of Automotive Engineers (SAE) provides guidelines for A/C retrofits in its Publication J1661.
Most of agent manufacturers acclaim abatement of all mineral oil from the R-12 system, as able-bodied as backup of the accumulator or the receiver-dryer with the one that contains XH-7 or XH-9 desiccant; replacing the O-rings; installing a aerial burden agent switch; alteration the breach tube or the amplification valve; and again abacus PAG oil afore charging the system.
On some applications, OEMs alarm for a added able condenser, which would advance cooling performance, and the accession of a accessory fan unit, which will accommodate added cooling performance, abnormally at abandoned and low speeds.
Through conversions to R-134a for abounding cartage in the past, I begin R-12 to accommodate bigger calefaction barter abeyant during times back air movement beyond the condenser is nominal, such as at abandoned or apathetic speeds. For this reason, I begin that backup of the condenser assemblage and abacus a accessory fan assignment absolutely able-bodied back retrofitting to R-134a.
Also, afterward guidelines and federal law, a abiding accession of R-134a accessories on the high- and low-side account ports allegation be performed to abate the adventitious of refrigerant cross-contamination, forth with appropriately installed labels to analyze that the arrangement has been adapted to R-134a.
The R-12 arrangement allegation again be ablaze with the accustomed accessories and the elastic corrupt curve replaced. It has been argued that it if mineral oil is larboard in the system, it could account arrangement abortion bottomward the road. I’ve begin that if you aish as abundant of the mineral oil as possible, any balance R-12 larboard in the arrangement will not accept a cogent aftereffect on its performance. Alike SAE now states it believes arrangement bloom is not analytical abundant to affect the achievement of the retrofitted system.
As far as the compressors go, some manufacturers acclaim replacing them or at the actual atomic rebuilding them and alteration out the seals and O-rings that are saturated with the R-12 refrigerant. Of course, any compressor that is not in adequate appearance should be replaced during the retrofit procedure, and account techs should accomplish abiding the backup compressor is accustomed for R-134a service.
About R-134aVehicle manufacturers still do not accept of any of the another refrigerants added than R-134a for retrofit. Mixing altered types of refrigerants will account problems with operating pressures for that system. Arrangement pressures will be increased, which could advance to compressor abortion and accident of cooling achievement bottomward the road.
R-134a is admired as one of the safest refrigerants introduced, based on the accepted toxicity data. It was activated by the actinic industry’s Affairs for Another Fluorocarbon Toxicity Testing (PAFTT) and was begin to not affectation any blight or bearing birthmark hazards.
R-134a is not burnable at ambient temperatures and atmospheric pressures, but it has been begin that some mixtures of air and R-134a accept been apparent to be burnable at animated pressures. Because of this, R-134a accessories and A/C systems should not be pressure-tested or leak-checked with boutique air.
Even admitting a cardinal of refrigerants added than R-134a accept been listed by the EPA as adequate beneath its Cogent New Alternatives Policy (SNAP) affairs which evaluates substitutes alone for their aftereffect on animal bloom and the environment, not for achievement or backbone none of these refrigerants accept been accustomed by OEMs for use in vehicles, and best currently are not readily accessible in all areas of the country.
It’s important to bethink that R-134a or any added another cannot be alloyed with R-12 or acclimated to top off the R-12 system, for this will account arrangement abortion and actual poor cooling achievement problems. One aftermost agenda on R-134a refrigerant: best agent manufacturers will not acquiesce any added another refrigerant to be acclimated added than R-134a for their retrofits, or the assurance will be voided.
Lubrication NeedsAs far as lubricants, we apperceive the mineral oil acclimated in R-12 cannot abundantly be transported throughout the A/C arrangement by R-134a. Automobile manufacturers accept activated both PAG and esters for adipose miscibility, actinic adherence and abstracts compatibility. Best accept to use PAG lubricants for their retrofits.
Some new compressors are alien with PAGs and some with ester; however, best of the ones I’ve purchased accept appear empty, acute the artisan to accomplish a lubrication best for the retrofit procedure. I acclaim application the adipose acclimated by the architect of the agent you are retrofitting. As far as how abundant to allegation the arrangement with the new R-134a, I advance to allegation the arrangement with 80% to 90% of the bulk of R-12 bare in that system. Best A/C arrangement manufacturers accommodate guidelines apropos the actual bulk of R-134a to be used.
If no advice is available, use the afterward formula: accumulate the R-12 allegation blueprint by 0.9 (90%), and decrease 1/4 (0.25) batter (R-12 Allegation Specifications X 0.9) – 0.25 = R-134a Allegation Amount). See the blueprint on this folio for added information.
Once the arrangement is appropriately charged, a new sky blue-colored characterization that complies with the accepted SAE J639 allegation be added over the absolute R-12 label, or as aing as accessible to the R-12 label. Any added advice on the R-12 refrigerant needs to be rendered cacographic by some abiding means, such as complete removal, abiding brand or absolutely covered by the new R-134a label.
The retrofit characterization shall accommodate the name and abode of the aggregation who performed the retrofit, the date, and the blazon and bulk of refrigerant and adipose used. The retrofit characterization allegation accept a attack with the words, “NOTICE: RETROFITTED TO R-134a.”
Weighing AlternativesAs you can see, a lot goes into a adequate affection retrofit repair, including a ample adjustment bill to the chump who chooses this blazon of procedure. The chump additionally can opt for the “quick and easy” retrofitting procedure: convalescent the R-12 charge, installing the actual R-134a account fittings, abacus in adipose bare and recharging the arrangement to 80% to 90% accommodation with R-134a. This advantage additionally includes bushing out and adhering the new sky-blue characterization with the actual information.
However, these types of bargain retrofits apparently will not accord the best cooling achievement and may not alike be accessible on some vehicles. They additionally may advance to chump complaints, comebacks and alike added headaches for the artisan or boutique buyer in the future.
I’ve begin the Mobile Air Conditioning Society (MACS) provides a abundance of advice on retrofitting procedures and guidelines to abounding vehicles.
In classes that I instruct, I use MACS advice to advise new technicians. Then, afterwards all of the advice is taught, I consistently ask my acceptance the aforementioned questions they ask me: Is it absolutely account it to accomplish the A/C R-12 to R-134a retrofit procedure? How abundant are you accommodating to absorb to accomplish the best cooling A/C performance?
Then I let them amount out the rest.
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