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p Figure 1 - Chrysler IHX. Note how the design combines the liquid and suction (vapor) lines.
customer complaints much sooner than a conventional R-134a
system. This leads to more service opportunities and dictates a
new level of system analysis to ensure a proper first-time repair.
The significant difference in an R-1234yf system is the addition
of a component known as an inline heat exchanger (IHX).
The heat exchanger is located within the accumulator within
most orifice tube systems. Expansion valve systems generally
bundle the IHX into a separate part which is easily identifiable
due to the dual inlet and outlet fittings on each end. The heat
exchanger is simply two tubes, so replacement is not needed during
regular service or repair unless there has been some damage.
The IHX operates under the same principles as any other
heat exchanger, such as a radiator or intercooler. Liquid refrigerant
leaves the condenser; it passes through
the inside chamber of this exchanger,
while the cooler refrigerant gas flows
out of the evaporator and through the outer
chamber of the IHX on its way to the compressor
(Figure 1). This creates a sub-cooling
effect and helps counteract the reduced
cooling capacity of R-1234yf.
CHOOSING A RECOVERY/
RECYCLING/RECHARGING SYSTEM
Now that we have a solid knowledge base to
work from let's start with the machine. There
are a few options for machines beginning
with the overall unit design. There are both
single units and combination units. Single
units are generally available at a lower price
point and have a smaller footprint, ideal for
shops where storage and working space are
at a premium. The combination units are
essentially two machines in one, allowing
for the service of R-134a or R-1234yf on a single platform at a
substantially higher price. The downside to utilizing a combination
machine is the length of time to switch from one refrigerant
to another, the process usually taking between 10-15 minutes
depending on the machine purchased.
The newest machines, at least those that are SAE J2843 compliant,
operate a bit differently than the standard R-134a machines
of the past and require more time and patience when performing
a service. The significant points are:
* Specialized couplers and fittings for R-1234yf.
* The internal filter drier will need to be replaced after recovering
150 lbs of refrigerant; otherwise, the machine will prevent
further operation until filter replacement.
* The unit must have an internal refrigerant
identifier or a USB port to connect a
separate unit.
* SNAP-ON VERUS EDGE
* SNAP-ON POLARTEK DUAL
MACHINE, NO. EEAC334B
* POWER PROBE DUAL
ZONE DIGITAL WIRELESS
THERMOMETER, NO. TEMPKIT
* SNAP-ON REFRIGERANT LEAK
DETECTOR, NO. ACT900
* MASTERCOOL 50W/12V UV
LIGHT, NO. 53312
* MILWAUKEE TOOL M12
THERMAL IMAGER,
NO. 2260-21
* NU-CALGON EVAP FOAM NO
RINSE CLEANER, NO. 4171-75
* It will not allow recovery of contaminated
refrigerant.
* It will not recharge the system if it detects
a leak.
The machines are essentially fully automatic,
with a few caveats referenced above.
The first is contaminated refrigerant. The
machine begins recovery by performing
a refrigerant identification. Suppose
the contents of the system are less than
98 percent pure R-1234yf. In that case,
a separate recovery tank/machine will
need to be connected to the designated
service port on your machine to continue
the evacuation of the system. This is an
essential requirement to consider when
purchasing a machine, as there will be
additional costs.
www.VehicleServicePros.com MARCH 2022 PROFESSIONAL TOOL & EQUIPMENT NEWS 33

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March 2022

Table of Contents for the Digital Edition of March 2022