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A primer on air conditioning service: what to know about changes in
refrigerant and tooling
A look at the differences and similarities between R-1234yf refrigerants, and the tools and
equipment necessary to service vehicles with this refrigerant.
While a seasonal opportunity for most shops, the HVAC system has become an integral part of
any vehicle on the road today.
Like most vehicles on the road, technology is forever changing.
This article covers updates in regulations with refrigerants, specifically changes to industry
usage of R-1234yf refrigerant.
Regulations and changes
Vehicles on the road today will primarily have R-134a refrigerant. However, OEs have begun to
adopt use of a new refrigerant, R-1234yf, in response to the impact of refrigerants on the
environment.
While carbon dioxide was the refrigerant of choice during the early 20th century, it was later
replaced with synthetic chemicals. Although carbon dioxide is a global-warming gas,
conventional refrigerants, called hydrofluorocarbons, cause about 2,000 times more global
warming than the same quantity of carbon dioxide.
The adoption of R-1234yf refrigerant began with regulations adopted in European countries.
While no regulations have been set in the U.S. yet, automotive manufacturers are beginning to
adopt the use of R-1234yf refrigerant for late model vehicles. This is because the government
has set up Corporate Average Fuel Economy (CAFÉ) standards that provide credit for using a
refrigerant that’s seen to have a lesser impact on global warming.
European standards used a comparison of Global Warming Potential (GWP) to determine the
efficiency and global impact of a refrigerant on the atmosphere. New Euro standards require a
GWP of less than 150 to be considered for use in A/C systems.
In terms of the differences between R-1234yf refrigerant, compared to previous types of
refrigerant, R-1234yf has a significantly lower GWP number.
With a basis of 1 for carbon dioxide (CO2), R-1234yf has a GWP of 4. Previous refrigerants
have much higher numbers, including R-134a with a GWP of 1,430.
To put that in perspective: According to global research- and technology-based science
company DuPont, the atmospheric lifetime for R-1234yf is 11 days, compared to R-134a which
stays in the atmosphere for up to 13 years.
(For a list of current manufacturers that are including the new refrigerant in their vehicles, go to
www.VehicleServicePros.com/12056013.)
While many alternatives to R-134a refrigerant were analyzed, including R-152a and R-744
(CO2), R-1234yf was selected based on its similarity to R-134a. Studies have been conducted
to determine that R-1234yf has good refrigeration properties, similar to R-134a.
One item of note with R-1234yf refrigerant is its classification as “mildly flammable,” which has
been deemed safe for use in all modern vehicles designed to use R-1234yf, subject to use
conditions by the EPA.
Basics of the A/C system
The HVAC system in some newer vehicles includes both the heating and cooling elements
combined into one serviceable unit, while the A/C and heating elements are separate in others.
A customer will generally stop into a shop due to an issue with air conditioning, versus stopping
in for routine maintenance.
Problems with a customer’s vehicle can include an issue with A/C electronics (the vehicle’s
computer system’s operation), a component or system failure or a leak in the system.
The right product for your customer
So what is the customer looking for in terms of A/C service tools and equipment? There are a
number of different options for tooling up a shop, from starting service with a new
Recover/Recycle/Recharge (RRR) system, to adding on or replacing accessories necessary for
general upkeep.
General overview of products used for A/C service
The Mobile Air Conditioning Society (MACS), a non-profit trade association for total vehicle
climate and thermal management, has a full list of suggested products to have on-hand in a
shop that plans to conduct any type of A/C service:
1.
2.
3.
4.
5.
6.
7.
8.
9.
Refrigerant identifier
Electronic leak detector
UV dye type leak detection system
Sealant detector
R-134a recovery/recycling machine SAE J2788 Compliant (best choice)
R-134a manifold gauges (if not included in other equipment)
Vacuum pump (if not included in other equipment)
Refrigerant weighing scale (if not included in other equipment)
Various temperature measuring devices, such as dial thermometers, digital pyrometers,
infrared thermometers, etc.
10. Digital multimeter
11. Scan tool
12. Hose repair crimping tool (if not included in other equipment)
13. Spring lock coupling disassembly and service tools
14. Specialized serpentine belt service tools
15. A/C service fitting service tools
16. Orifice tube service tools
17. Service Information – manuals, specification books, computerized information system, etc.
18. Cooling system pressure tester
19. Cooling system flush and recycling equipment
20. Of course, “the regular full complement” of standard hand tools, air tools and safety
equipment, as well as the “normal” shop tools, such as air compressor, bench grinder,
press, workbenches, drop lights, drain pans, etc.
Refrigerant identification, sealants and sealant testing
Before beginning any A/C work on a vehicle, it’s important to first determine what type of
refrigerant is used in the A/C system to avoid refrigerant cross-contamination, as well as if any
sealant was added to the system.
There are a number of different refrigerant analysis tools on the market, as well as sealant
testers to assist with this testing.
“Although sealants are used quite often in an attempt to quickly repair vehicle air conditioners,
they are not approved for use by any vehicle OEMs,” says Steve Schaeber, manager of service
training for the MACS. A vehicle owner may purchase sealant to add to the A/C system without
this knowledge, then taking it into the shop without notifying the technician, which can cause
issues.
“Because of the harm they can cause inside RRR equipment, damage to these machines
caused by sealant is not covered under warranty.”
“MACS recommends using a sealant detection device to determine if sealant is present in a
vehicle’s A/C system as a preventative measure, prior to connecting any other tools, such as
pressure gauges, a refrigerant identifier or an RRR machine,” says Schaeber.
There are many tools available from air conditioning tool equipment manufacturers such as
Mahle and Neutronics.
“If sealant were allowed to enter your tools or test equipment, it could cause extensive damage
by solidifying in solenoids, tubing and other components.”
Leak detection
“If a vehicle comes in and there’s no refrigerant, A/C is a closed system, so there must be a leak
somewhere,” says Tim Wagaman, senior product manager of air conditioning and fluid products
for Robinair, an air conditioning product manufacturer and division of Bosch Service Solutions.
“It’s important to find the leak so you know what you have to fix. The minute you put refrigerant
back into the system, it’s going to start leaking again.”
There are two primary ways to search out leaks in an A/C system: through an electronic leak
detector, or by adding UV dye to the system.
Also known as a refrigerant sniffer, this tool uses a wand-like device that’s waved around
different areas of the A/C system, including components and connections.
“(The electronic leak detector) brings in air, and if there’s refrigerant that’s brought in as well, it
will pinpoint where that leak is coming from,” says Wagaman. This method works well for
spotting larger leaks on areas of the vehicle that are easier to access.
For pinpointing leaks in tight or difficult-to-reach areas, technicians can add a UV dye to the
system.
UV dye gets injected into the system when the vehicle is at the shop. The dye needs time to
circulate in the system, so oftentimes customers will be sent home to drive the vehicle for a
couple days. If there is a leak in the system, some of the residual dye will show up outside of the
system. Technicians spot this by completing a thorough search around the vehicle’s A/C system
using a UV flashlight.
Some OEs, such as GM, are now adding UV dye directly to the A/C system during assembly
when it comes off the manufacturing line.
Pressure and temperature testing
According to MACS’ Schaeber, almost every tech today who works on A/C systems owns a set
of manifold gauges for pressure testing. “It’s been one of the most important and widely used
A/C tools since the first systems were installed over 75 years ago,” he says. “They are used to
test a system for pressure, pressure decay, vacuum and vacuum decay to determine the
condition of system components.”
Because A/C systems transfer heat, Robinair’s Wagaman explains, “If you know what the
pressure is, you’re going to have a fairly good idea of what the temperature is of that refrigerant
in that A/C system.”
As the refrigerant circulates, and goes through the evaporator, it blows cold air and takes the
heat of the refrigerant, absorbs the heat and warms the refrigerant.
According to Schaeber, temperature testing is a relative newcomer to the diagnostic side of A/C
systems. He advises tools used for temperature testing can verify system performance,
component performance, as well as help determine the state of the charge of the A/C system.
“MACS recommends using a direct contact-type thermocouple device to obtain the most
accurate measurements possible,” says Schaeber. There are a variety of tools available,
including the GPD A/C Diagnostics Tool (No. 41-11585) which features flexible direct contact
thermocouples for quick and accurate temperature readings.
Chemical flushing versus liquid flushing
Every shop looking to complete any type of A/C service should consider a method to flush
contaminants from the system – either through chemical flushing or through liquid flushing.
“Liquid refrigerant flushing is using the refrigerant as the medium to flush an A/C system.
Chemical flushing is using a chemical solvent to flush the A/C systems,” says Robinair’s
Wagaman. Many times, the process for flushing the system is dependent on OE
recommendations.
Chemical flushing is generally used when a more substantial failure has occurred in the A/C
system. A different standalone system is used for chemical flushing, where a separate solvent is
used to flush the A/C system.
Regarding chemical flushing, MACS’ Schaeber advises many manufacturers do not recommend
it be performed. “Open vent flushing often will not remove debris from a system.”
He continues, “Connecting flush equipment to the system service ports, even with the valve
cores removed, will not provide adequate system flushing, and may not result in the removal of
debris and other substances.” Instead of this process, he says many OEs advise the use of inline filters to effectively trap debris in the system.
“Many A/C system and component manufacturers also have reservations concerning the use of
solvents to flush systems,” says Schaeber. “Other than possible ineffectiveness, the
manufacturers’ main area of concern is the fact that some solvent may remain in the system,
because depending upon a solvent’s boiling point, a vacuum pump may not remove all of it,
even after a prolonged deep vacuum.”
Liquid flushing, also known as refrigerant flushing, is completed by shops using an RRR
machine.
Any shop looking to complete liquid flushing should have an RRR machine.
“When you look at servicing A/C systems, it’s all about being able to get the refrigerant out,
being able to fix the system, being able to pull air out of the system, and being able to get
refrigerant back into the system,” says Wagaman. This is all done with an RRR machine.
Wagaman explains that there are actually four steps to the process:
1. Recover the refrigerant from the vehicle, onto the machine.
2. As the refrigerant is recovered from the vehicle, it goes through a recycling process,
where all impurities are removed from the refrigerant.
3. Once this process is completed, it’s important to evacuate the system of any air or
humidity to create a vacuum.
4. The pure refrigerant than must be recharged back into the A/C system, along with
adding any additional refrigerant to fill the system.
“Shops should use RRR machines certified to the latest SAE standards,” says Schaeber. For R134a, he explains that the J2210 recovery/recycling equipment standard was updated in 2007 to
SAE J2788. “The J2788 equipment standard provides more complete refrigerant recovery, and
also establishes refrigerant charging requirements providing greater accuracy,” he says.
“Also in 2007, recovery-only equipment standard SAE J1732 was superseded by SAE J2810.
J2810 equipment provides more complete refrigerant recovery.”
There are a number of product features and functionality that shops can consider when
purchasing an A/C machine. Some include:
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A unit certified to the latest SAE standards. This includes SAE standard J2788 for use
with R-134a refrigerant, or J2843 for use with R-1234yf. If a unit is capable of servicing
both types of refrigerant, it should meet SAE standard J3030.
A dual system that can service both R-1234yf and R-134a refrigerants, without
contamination.
A system that allows for servicing both traditional and hybrid vehicles, because different
oils are used for each system.
Onboard or manual oil injection systems. With a hybrid unit, you may have manual oil
injection (due to the different oil types used in different vehicles).
Self-calibration versus having a service provider complete calibration.
An automated flushing process, where users can follow instructions on the RRR unit to
complete the service.
Foam wheels versus pneumatic wheels, for maneuverability of the unit around the shop.
Vehicle capacity database, which provides oil capacities for components in each vehicle.
The product warranty. Shops will look at the length of the warranty, and the
serviceability, whether or not they’re responsible for making repairs, or if a third party
must come in to complete these repairs.
Different tools for R-1234yf
While some tools, such as temperature measuring devices and weighing scales, can be used
with any type of refrigerant, some tooling will need to be updated in shops if they plan to service
vehicles with R-1234yf refrigerant. When updates to a tool are made, new SAE standards are
applied to these products.
“To prevent system contamination, all refrigerants used in mobile air conditioning vapor
compression systems require unique service fittings and service equipment. The unique service
fittings are intended to eliminate the potential for system refrigerant cross-contamination during
service activity,” says MACS’ Schaeber.
“The law requires that the service fittings and connectors be unique for each refrigerant used,”
says Schaeber. “This requirement prevents contamination by assuring that service equipment
for one refrigerant will not connect to a system using a different chemical.”
Here is a list of updated standards for R-1234yf tools and equipment:
R-1234yf RRR Equipment (SAE J2843)
According to SAE International: This SAE Standard applies to equipment to be used with R1234yf refrigerant only. It establishes requirements for equipment used to recharge R-1234yf to
an accuracy level that meets Section 9 of this document and purity levels defined in SAE J2099.
Refrigerant service equipment is required to ensure adequate refrigerant recovery to reduce
emissions and provide for accurate recharging of mobile air conditioning systems. Equipment
shall be certified to meet all performance requirements outlined in this document and
international/regional construction and safety requirements as outlined in this document.
http://standards.sae.org/j2843_201301/
R-1234yf Refrigerant Diagnostic Identifiers (SAE J2912)
According to SAE International: This SAE Standard applies to refrigerant identification
equipment to be used for identifying refrigerant HFC-134a (R-134a) and HFO-1234yf (R-1234yf)
refrigerant when servicing a mobile A/C system or for identifying refrigerant in a container to be
used to charge a mobile A/C system. Identification of other refrigerants is the option of the
equipment manufacturer, although it shall not misidentify refrigerants.
http://standards.sae.org/j2912_201311/
Updated Service Couplers (SAE J2888)
According to SAE International: This SAE Standard covers fittings, couplers, and hoses
intended for connecting service hoses from mobile air-conditioning Systems to service
equipment such as charging, recovery and recycling equipment. (Figure 1) This specification
covers service hose fittings and couplers for mobile air--conditioning service equipment service
hoses, per SAE J2843 and SAE J2851, from mobile air conditioning systems to service
equipment such as manifold gauges, vacuum pumps, and air conditioning charging, recovery
and recycling equipment. http://standards.sae.org/j2888_201102/
Equipment certifications and standards
A new J3030-certified dual refrigerant recovery, recycling and recharging technology may be
approved by SAE. Timing of an approval is uncertain.
“This is a dual-refrigerant machine that can be used for both R-134a and R-1234yf with the flick
of a switch,” says Neutronics’ Coll. “Anyone looking for a R-134a machine today should
consider a J3030 machine that can be used today and tomorrow."
SAE certified productivity ensures the machine will operate with specific equipment
performance, purity and safety guidelines for the recovery and recycling of motor vehicle
refrigerant. Refer to the SAE J2788 guideline for R-134a refrigerant and the SAE J2843
guideline for R-1234yf refrigerant before purchasing a manufacturer’s product.
Complexities and changes in the A/C system
Contamination in the system
Different RRR machines and other A/C equipment should be used for different types of vehicles,
to avoid cross-contamination.
There are two main types of cross-contamination that can occur when servicing A/C systems:
refrigerants and oils.
Each vehicle has a required refrigerant recommended for use by the OE. Refrigerant crosscontamination occurs when a different refrigerant is added to a system. For instance, R-134a
refrigerant that has been added to a system that requires R-1234yf refrigerant.
“Once you start adding other items, it could cause the system to act differently than it normally
would. It may not operate as efficiently. From a customer standpoint, they may not notice cold
air blowing out of the vents. It’ll affect the overall performance of the A/C system,” says
Robinair’s Wagaman.
The other type of cross-contamination occurs when two oils are mixed together.
Traditional A/C systems use belt-driven compressors, with a PAG-based oil. With the adoption
of electric vehicles (both fully electric and hybrid electric), a high-voltage electric compressor is
generally used in the A/C system. With this system, a POE-based oil is required, because POE
doesn’t attract moisture or conduct electricity. Some equipment manufacturers, including
Mastercool and Mahle, offer RRR machines that is capable of servicing both traditional and
hybrid vehicles in one unit.
“Different PAG oils have the potential to absorb water and moisture and conduct electricity. The
technician must ensure the use of non-conductive oil, such as POE oil, when working on a
hybrid vehicle with hermetically sealed compressors,” says Eric Shultz, engineering manager,
MAHLE Service Solutions.
“The oil that circulates in the system is used to lubricate the compressor. When you hook up an
RRR machine to the system and pull that refrigerant system, you’re likely going to pull some of
that oil out,” says Robinair’s Wagaman.
“SAE approved A/C service models for hybrid vehicle service requires manual oil injection,
putting the responsibility of the oil selection back to the technician to ensure safe operation of
the equipment,” says Mahle’s Shultz. “Understanding your shop’s market needs will help you
choose the best suited machine.”
Selling to the shop
What does the average A/C repair cost? Mahle has an ROI calculator, with a chart on how to
recoup the costs of a machine.
This calculator can aid distributors in helping shops determine which product is right for them.
Questions to ask shops
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How old is the equipment they’re using?
It’s important to determine the age of the equipment shops are using. Equipment in operation
today should be J2788 certified. Any RRR machines in service purchased prior to 2007 should
be replaced due to updated efficiency standards. These older units sometimes only pull 70
percent of the refrigerant out of the vehicle.
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If you’re already offering A/C service, do you use an automatic or manual machine?
An upgrade to an automated machine may help a shop be more efficient, with less user error.
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How much A/C service are they performing in an average week, or how much A/C work
do they anticipate doing in an average week if they’re planning to add this service?
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How do they find and fix leaks within an A/C system?
Does the shop have different types of thermometer and temperature devices? Do they utilize a
UV dye and flashlight system?
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Do they service hybrid electric vehicles?
If so, they should be aware of the difference between belt-driven compressors on traditional
vehicles, that require PAG-based oil, and electric-driven compressors on hybrid vehicles, that
require POE-based oil. Contamination of these oils may cause damage to a vehicle’s A/C
system, particularly for hybrid vehicles.
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Are they certified to perform A/C service?
“All technicians who work on mobile air conditioning systems for consideration are required to
be certified under Section 609 of the US Clean Air Act,” says MACS’ Schaeber. “There are
several ways for technicians to become certified through MACS, including self-study, online
testing and proctored training.”
As of Jan. 1, 2015, MACS has released their newest version of this training, with updates on
refrigerants such as R-152a, R-744 (CO2) and R-1234yf.
MACS certification, in partnership with the EPA, was developed to teach techs how to safely
handle refrigerants. The 609 certification is required for all technicians that will repair or service
vehicle air conditioning systems. This training will ensure safety for your staff, customers and
the environment, according to Mahle’s Shultz. Currently, this is a one-time certification.
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Have they performed the necessary routine maintenance for their RRR unit?
According to Mahle’s Shultz, SAE certified machines require the desiccant filter to be changed
after recycling 150 lbs of refrigerant. It is recommended to change in-line filters at this time as
well. Aside from the filter, other maintenance items include an annual calibration and that the
vacuum pump oil is changed at regular intervals. The service hoses and couplers also should
be inspected regularly for wear and for vacuum leaks not visible to the naked eye.