924 / 1003
9
Chapter
Refrigerants
• Description and Properties of Refrigerants
• Changes in Service Procedures
• Recovering and Recycling the Refrigerant
• Flushing the AC System
• Evacuating and Charging the AC System
• Reclaiming a Refrigerant
• Chapter Review
Description and Properties of Refrigerants
Refrigerants are contained in the closed system of an air conditioner and
circulate under pressure, moving heat energy from the cab to the outside air.
Different refrigerants require different operating pressures, causing the refrig-
erant to undergo a “change of state” (refer to
Chapter 1 — HVAC Function
).
Changes in Service Procedures
Since the beginning of 1992, the EPA has required that any refrigerant re-
moved from an AC system be recovered and recycled before reuse. Unlike the
purging process which releases ozone depleting refrigerant into the atmo-
sphere, the recovery processes allow us to use the same refrigerant over and
over.
RECOVER
RECYCLE
RECLAIM
A major difference between purge and recovery/recycle procedures is the refrig-
erant is contained in an externally sealed container when undergoing recovery/
recycle procedures in order to ensure environmentally safe processing.
In order to reuse a refrigerant in an AC system, the following steps are
required:
1.
Prepare the station for the recovery process
2.
Recover refrigerant from the AC system
3.
Recycle the recovered refrigerant
4.
Perform the maintenance or repair the system
5.
Flush the AC system when necessary
6.
Evacuate the AC system
7.
Charge the AC system with recycled refrigerant
9-1
Go to Table o f Contents - IndexClick on any of these
subject headings to go
directly to the page