ACtion Magazine - Napa Special Edition - June 2017 - 16

Retroﬁtting R-1234yf mobile air conditioning systems is prohibited

The SNAP July 2015 final rule (80 FR 42953) states
that "HFC-134a is listed, and will remain listed, as an
acceptable refrigerant for retrofit of existing systems designed to use CFC-12, but because of the use restrictions
for refrigerants listed as acceptable, it cannot be used as a
retrofit for MAC systems using other alternatives." For more information, see https://www.epa.gov/snap/
... topping
motor-vehicle-air-conditioning.

person who violates the defeat device prohibition, (3)
(Bl), is subject to a maximum civil penalty of $2,500 per
violation. Any such violation with respect constitutes a
separate component."

Clean Air Act Section 203(a)(3)(A):

There are several design issues between the two refrigerants that may affect maximum cooling performance.
Since no information on the exchange of system refrigerant has been released by vehicle manufacturers, there is
no information on what may be encountered with a refrigerant change. This may include issues related to cooling
performance and durability.

It should also be noted that
since the 1993 letter the Statuoff/filling a vehicle sys- tory Penalties for "Tampering"
have increased from $25,000 to
tem designed for R-1234yf, which the current penalty of $37,500 for
Currently there are many new
has received emission credits, with a manufacturer or dealer. A 2016
proposal that is now in the interim
light-duty vehicles using R-1234yf,
any refrigerant other than R-1234yf, is final rule stage would increase
since the EPA has allowed manufacturers to apply credits from the
considered "tampering with a vehicle this to $44,539. The penalty for
a "Defeat Device" for an individuse of lower global warming refrigemissions-control device ual was $2,500 per violation and
erants toward the CO 2 emissions
would increase to $4,454.
and fuel economy standards. Use of
See https://www.federalanother refrigerant (Including R134a), due to the refrigerant circuit control calibrations, register.gov/articles/2016/07/01/2016-15411/civil-monewill cause the system to operate differently than it did in tary-penalty-inflation-adjustment-rule.
the design certified vehicle using R-1234yf.

"

"The following acts and the causing thereof are prohibited ...for any person to remove or render inoperative
any device or element of design installed on or in a motor
vehicle or motor vehicle engine in compliance with regulations under this subchapter prior to its sale and delivery
to the ultimate purchaser, or for any person knowingly to
remove or render inoperative any such device or element
of design after such sale and delivery to the ultimate purchaser;"
In an EPA vehicle emissions enforcement letter, dated January 14, 1993, the Office of Air and Radiation in
the CIVIL PENALTY POLICY FOR ADMINISTRATIVE
HEARINGS issued the following:
"A. Statutory Penalties (Page 6)
Tampering - Under section 205 of the Act, any manufacturer or dealer who violates the tampering prohibition, (3)(A), is subject to a civil penalty of not more
than $25,000 per violation. Any person other than a
manufacturer or dealer who violates the tampering
prohibition is subject to a civil penalty of not more than
$2,500 per violation. Any such violation with respect
to the tampering prohibition constitutes a separate offense with respect to each motor vehicle or motor vehicle engine.
Defeat Device - Under section 205 of the Act, any

16

ACTION/NAPA * Spring 2017

System cooling performance

Refrigerant flow devices
The expansion valve setting for R-1234yf refrigerant
is different compared to R-134a. Changing from R-1234yf
to R-134a refrigerant may result in a system with incorrect refrigerant flow and heat exchanger mal-distribution
which may cause a loss of cooling performance or durability concerns.
The TXV setting is also different when an Internal Heat
Exchanger (IHX) is used, which is common in R-1234yf
MAC systems. This may mean that suction line pressure
drop is increased, which might affect the setting for a
pressure controlled compressor, resulting in poor cooling
or evaporator core freezing.
This can be particularly damaging in the case of dual
evaporator systems where the balance of front and rear
expansion devices helps to avoid oil trapping in the rear
evaporator.

Evaporator control
Evaporator control settings are important both for
maximum performance and reduced load requirements at
cooler ambient. Depending upon the method of control for

https://www.epa.gov/snap/motor-vehicle-air-conditioning https://www.epa.gov/snap/motor-vehicle-air-conditioning https://www.federalregister.gov/articles/2016/07/01/2016-15411/civil-monetary-penalty-inflation-adjustment-rule https://www.federalregister.gov/articles/2016/07/01/2016-15411/civil-monetary-penalty-inflation-adjustment-rule https://www.federalregister.gov/articles/2016/07/01/2016-15411/civil-monetary-penalty-inflation-adjustment-rule

Table of Contents for the Digital Edition of ACtion Magazine - Napa Special Edition - June 2017