ACtion Magazine - April 2017 - 22

Auto and light truck service clinics

His presentation, titled Optimizing System Charge Levels for
Modern Replacement Condensers, provided MACS 2017 delegates
with an understanding of the condenser designs, relevant testing procedures and other considerations - punctuated by numerous case
studies and appropriate testing and diagnostic processes.
McArdle pointed out that since 1985, the average mobile A/C refrigerant charge level has more than halved, the average system lubricant charge has almost halved, but the average A/C system efficiency
has more than doubled. "New CAFE standards, AC17 emissions
testing, innovative technologies and sophisticated HVAC control
strategies have enabled this productivity in large part," he noted. "But
it comes at a price: proper equipment, tools, training and diagnostic
procedures are now essential for complete service and repair."
Consider determining the optimum refrigerant charge level for replacement condensers. Even a small system over- or undercharge can
have expensive consequences.
"Technicians must understand that if the system charge level is not
optimized to consider these differences, the system may not perform
satisfactorily. It may sometimes be necessary to adjust the system refrigerant charge level in replacement condensers to optimize system
performance. Be diligent, because overcharging and undercharging
systems are both problematic and expensive."
"Identifying underlying weaknesses in an HVAC system in advance as well as before returning the vehicle to the customer is a
sound business practice." McArdle shared how to place a vehicle under maximum stress in the bay at setup, before beginning service, to
more easily expose underlying A/C and cooling system weaknesses.
During his presentation, McArdle also provided several takeaways all A/C and cooling system professionals should be aware of:
*
Condenser Technology is Continually Advancing
- "As a vehicle ages, replacement parts may be
developed that are better or more efficient than the
original part. It's very common for the internal volume
and efficiency of replacement condensers to differ
significantly from the vehicle's original unit. "This rapid
evolution of air-conditioning technology can change how
diagnostics, testing and service are approached."
*
Sophisticated HVAC Control Strategies Increase
HVAC Diagnostic Difficulty - "Every component in
HVAC is fine tuned for maximum efficiency. To keep
pace with change and ensure service-readiness, properly
maintained shop equipment, tools and technician training
are essential. Technicians need to be cognizant of the
vehicle's new technologies and its associated diagnostic
and service procedures. That's why the specialized
training offered at MACS events is critical; it fosters
awareness of changes, showcases service issues and
remedies, and raises competencies."
*
Differential Temperature Testing is an Essential
Skill -"Optimizing the charge level is an exercise to
find the sweet spot. Differential Temperature Testing is
a powerful diagnostic and validation tool to identify and
diagnose air flow issues; it is also an ideal diagnostic
and validation practice to optimize charge levels." Using

22

ACTION * April 2017

a number of case studies, McArdle explained several
key points to remember and procedures to follow when
testing, to confirm that the system is truly repaired before
returning the vehicle to the customer.
"Finally, don't overlook checking air flow when investigating A/C
and cooling system performance issues. Just because a vehicle isn't
overheating doesn't mean it doesn't have a serious problem. Although
a small reduction in airflow might only result in a small increase in
engine temperature, it could lead to a significant increase in A/C head
pressure and associated poor system performance."
Figure 4: The days of treating customer A/C
complaints only as refrigeration problems are
over, according to Tim Iezzi. Instead, shops
and technicians must employ a scientiﬁc and
system-based diagnostic approach.

Diagnostic directions
Making the most of the first 5 minutes
"Diagnostics is science." With those three words, Tim Iezzi, an
aftermarket trainer and owner of Iezzi's Auto Service, began sharing
Diagnostic Directions: Making the Most of the First 5 Minutes,
his approach to mobile A/C and cooling system diagnostics. From
the reaction of attendees at MACS 2017, he opened more than a few
eyes.
"It's an algebraic process," Iezzi revealed. "We gather information we know to figure out why a system doesn't work. This logical problem-solving process can be applied to diagnosing real-world
automotive HVAC problems, as well as other vehicle system issues."
Unlike most of the MACS 2017 seminars, Iezzi prepped attendees upfront in his presentation with several key takeaways:
*
Building a Diagnostic Plan is Essential - "We
need a way to gather as much information as possible
as quickly as possible, to reach the root of the problem.
During this seminar, we will work together to build and
apply a repeatable diagnostic plan."
*
Source and Use Correct Service Information to
Understand How the HVAC System Works - "Without
knowing how the A/C requests are generated and
transmitted, a technician may not be able to fix a vehicle.
One of the case studies we will cover deals with an
issue spanning two communication networks. You'll be
surprised that it isn't as difficult as it first seems."
*
Mobile Air Conditioning Systems Are Not StandAlone - "In order to be able to service or repair modern
air conditioning systems on vehicles, you need to be a
diagnostician, understand engine controls and be familiar
with vehicle network communications."
Iezzi then outlined the basics of the diagnostics regimen he employs and showed how to build a diagnostic plan (see image). He also
distributed a "Composite Vehicle A/C System Model" he developed,
which attendees used as he guided them through several interactive
case studies that reinforced how to apply the diagnostic process.

Table of Contents for the Digital Edition of ACtion Magazine - April 2017

Outlook
Service Port
Leonard's Law
Virtual View
Member Profile
Auto and light truck service clinics
By the Numbers
Review of heavy duty/off road vehicle tech
Marketing panel
Industry News
Association News
New Products
Last Watch
ACtion Magazine - April 2017 - Cover1
ACtion Magazine - April 2017 - Cover2
ACtion Magazine - April 2017 - 3
ACtion Magazine - April 2017 - 4
ACtion Magazine - April 2017 - 5
ACtion Magazine - April 2017 - Outlook
ACtion Magazine - April 2017 - 7
ACtion Magazine - April 2017 - Service Port
ACtion Magazine - April 2017 - 9
ACtion Magazine - April 2017 - Leonard's Law
ACtion Magazine - April 2017 - 11
ACtion Magazine - April 2017 - Virtual View
ACtion Magazine - April 2017 - 13
ACtion Magazine - April 2017 - Member Profile
ACtion Magazine - April 2017 - 15
ACtion Magazine - April 2017 - 16
ACtion Magazine - April 2017 - 17
ACtion Magazine - April 2017 - Auto and light truck service clinics
ACtion Magazine - April 2017 - 19
ACtion Magazine - April 2017 - By the Numbers
ACtion Magazine - April 2017 - 21
ACtion Magazine - April 2017 - 22
ACtion Magazine - April 2017 - 23
ACtion Magazine - April 2017 - 24
ACtion Magazine - April 2017 - 25
ACtion Magazine - April 2017 - 26
ACtion Magazine - April 2017 - 27
ACtion Magazine - April 2017 - 28
ACtion Magazine - April 2017 - 29
ACtion Magazine - April 2017 - Review of heavy duty/off road vehicle tech
ACtion Magazine - April 2017 - 31
ACtion Magazine - April 2017 - 32
ACtion Magazine - April 2017 - 33
ACtion Magazine - April 2017 - Marketing panel
ACtion Magazine - April 2017 - 35
ACtion Magazine - April 2017 - 36
ACtion Magazine - April 2017 - Industry News
ACtion Magazine - April 2017 - 38
ACtion Magazine - April 2017 - Association News
ACtion Magazine - April 2017 - 40
ACtion Magazine - April 2017 - 41
ACtion Magazine - April 2017 - 42
ACtion Magazine - April 2017 - 43
ACtion Magazine - April 2017 - New Products
ACtion Magazine - April 2017 - 45
ACtion Magazine - April 2017 - Last Watch
ACtion Magazine - April 2017 - Cover3
ACtion Magazine - April 2017 - Cover4
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