1. R1 Fundamentals of Refrigeration
R1 Fundamentals of Refrigeration - Subject 3 Recovery, Evacuation, Charging v1.1
5/21/2018
R1 Fundamentals of Refrigeration
#3 Recovery, Evacuation, Charging
© 2004 Refrigeration Training Services
No reproduction or unauthorized use allowed

2. Manifold Gauge Set High and Low side gauges Close valves on gauges
R1 Fundamentals of Refrigeration - Subject 3 Recovery, Evacuation, Charging v1.1
5/21/2018
Manifold Gauge Set
High and Low side gauges
Close valves on gauges
Read system pressure with valves closed
© 2004 Refrigeration Training Services - R1 Subject 3 Recovery, Evacuation, Charging v1.2
© 2004 Refrigeration Training Services
No reproduction or unauthorized use allowed

3. How a Manifold Gauge Set Works
Gauge Manifold
Close left handle
Close right handle
To Low Side
To High Side
Low Pressure
High Pressure
Center port for evacuation and charging
© 2004 Refrigeration Training Services - R1 Subject 3 Recovery, Evacuation, Charging v1.2

4. Hook up gauges to service valves
Discharge service valve
High pressure gauge (red)
Suction service valve
Low pressure gauge (blue)
© 2004 Refrigeration Training Services - R1 Subject 3 Recovery, Evacuation, Charging v1.2

5. Installing Gauges Hook up gauges
Gauge Manifold
Hook up gauges
Crack service valves to read system pressures
Path of refrigerant
CONDENSER
Compressor
EVAPORATOR
Receiver
TEV
Sight Glass
Filter-Drier
© 2004 Refrigeration Training Services - R1 Subject 3 Recovery, Evacuation, Charging v1.2

6. Recovering Refrigerant
Recovery machine is just a compressor
Pumps vapor only
Inlet is the suction side of compressor
Outlet goes to recovery tank
Recovery tank acts as a condenser
© 2004 Refrigeration Training Services - R1 Subject 3 Recovery, Evacuation, Charging v1.2

7. Refrigerant now in tank
Vapor Recovery
Start recovery
Gauge Manifold IN
OUT
Recovery
Unit
Recovery
Cylinder
Open valve
Now open high side gauge valve
Scales
CONDENSER
Compressor
EVAPORATOR
Refrigerant now in tank
TEV
Sight Glass
Filter-Drier
Receiver
© 2004 Refrigeration Training Services - R1 Subject 3 Recovery, Evacuation, Charging v1.2

8. Recovery Completed
Gauge Manifold
All refrigerant is recovered when unit pulls a vacuum. IN
OUT
Recovery
Unit
Recovery
Cylinder
System now ready for removal, repair, etc.
Scales
CONDENSER
Compressor
EVAPORATOR
Receiver
TEV
Sight Glass
Filter-Drier
© 2004 Refrigeration Training Services - R1 Subject 3 Recovery, Evacuation, Charging v1.2

9. “Push-Pull” Liquid Recovery
Large units have a lot of refrigerant
Vapor recovery takes too long
Recovery unit can push liquid into tank
Then pull out remaining vapor
© 2004 Refrigeration Training Services - R1 Subject 3 Recovery, Evacuation, Charging v1.2

10. Liquid Refrigerant Recovery - "Push-Pull" Method
Gauge Manifold
Open high side gauge valve, IN
OUT
Both recovery tank valves,
Recovery
Cylinder
And the King valve
Turn on Recovery Unit, push liquid out of Condenser and Receiver, into recovery tank
Scales
Most of the liquid has been removed Begin vapor removal.
CONDENSER
Compressor
EVAPORATOR
Receiver
TEV
Sight Glass
Filter-Drier
© 2004 Refrigeration Training Services - R1 Subject 3 Recovery, Evacuation, Charging v1.2

11. Evacuated Tank Liquid Recovery
Pull a vacuum on a recovery tank
Connect to receiver
The tank will suck out liquid
Note: a cold tank will speed the transfer
© 2004 Refrigeration Training Services - R1 Subject 3 Recovery, Evacuation, Charging v1.2

12. Liquid Recovery: Evacuated Tank
Gauge Manifold
Recovery tank in a Vacuum
Liquid refrigerant can be removed without a recovery machine
Vacuum in tank removes most of the liquid
Use recovery unit to complete vapor removal
Scales
CONDENSER
Liquid is sucked out
Compressor
EVAPORATOR
Open King Valve on Receiver
Receiver
TEV
Sight Glass
Filter-Drier
© 2004 Refrigeration Training Services - R1 Subject 3 Recovery, Evacuation, Charging v1.2

13. Single Evacuation What is evacuation? Why? How long do you evacuate?
Pulling a vacuum on a system
Why?
To remove air and moisture
How long do you evacuate?
To 500 microns
© 2004 Refrigeration Training Services - R1 Subject 3 Recovery, Evacuation, Charging v1.2

14. System Ready for Charging
Single Evacuation
Shut off pump valve
Start Pump and open valves on Gauge Manifold
Gauge Manifold
500
Continue Vacuum to 500 microns
Vacuum Pump
Wait 5 min. to see if proper vacuum remains
Turn off pump
System Ready for Charging
CONDENSER
Compressor
EVAPORATOR
Receiver
TEV
Sight Glass
Filter-Drier
© 2004 Refrigeration Training Services - R1 Subject 3 Recovery, Evacuation, Charging v1.2

15. Multiple Evacuation For systems with lots of moisture:
Pull a vacuum to 1000 microns
Break vacuum with nitrogen
Pull a second vacuum to 1000 microns
Pull a third vacuum to 1000 microns
If system holds vacuum start charging
© 2004 Refrigeration Training Services - R1 Subject 3 Recovery, Evacuation, Charging v1.2

16. Multiple Evacuations: Step 1
Start pump and
open valves on gauge
Evacuate to 1000 microns
Shut off valve at pump
1000
Vacuum Pump
CONDENSER
Compressor
EVAPORATOR
TEV
Sight Glass
Receiver
Filter-Drier
© 2004 Refrigeration Training Services - R1 Subject 3 Recovery, Evacuation, Charging v1.2

17. Multiple Evacuations : Step 1
Break vacuum to about 2 psig
NITROGEN
Close valve to pump,
open valve to nitrogen
Nitrogen removes moisture
Vacuum Pump
1000
CONDENSER
Compressor
EVAPORATOR
TEV
Sight Glass
Receiver
Filter-Drier
© 2004 Refrigeration Training Services - R1 Subject 3 Recovery, Evacuation, Charging v1.2

18. Multiple Evacuations: Step 2
Close valves to nitrogen tank
Run compressor 5 seconds
Open valve to pump
Pull 2nd vacuum to 1000 microns
Vacuum Pump
1000
NITROGEN
NEVER start a compressor in a vacuum
CONDENSER
Compressor
EVAPORATOR
TEV
Sight Glass
Receiver
Filter-Drier
© 2004 Refrigeration Training Services - R1 Subject 3 Recovery, Evacuation, Charging v1.2

19. Multiple Evacuations: Step 2
Break vacuum with nitrogen
Vacuum Pump
1000
NITROGEN
CONDENSER
Compressor
EVAPORATOR
TEV
Sight Glass
Receiver
Filter-Drier
© 2004 Refrigeration Training Services - R1 Subject 3 Recovery, Evacuation, Charging v1.2

20. Multiple Evacuations: Last Step
Pull 3rd vacuum to 1000 microns
Vacuum Pump
1000
NITROGEN
CONDENSER
Compressor
EVAPORATOR
System Ready for Charging
TEV
Sight Glass
Receiver
Filter-Drier
© 2004 Refrigeration Training Services - R1 Subject 3 Recovery, Evacuation, Charging v1.2

21. Disposable Refrigerant Drums
Look for direction on drum:
Upright position, charge with vapor
Upside down, charge with liquid
Some manufacturers tried dip tubes
It is confusing, most stopped
© 2004 Refrigeration Training Services - R1 Subject 3 Recovery, Evacuation, Charging v1.2

22. Freon tanks R22 404A 404A Turn over for liquid R22 tank cut-a-way view
Originally R404A tanks had dip tubes
Now R404A tanks have NO dip tubes
© 2004 Refrigeration Training Services - R1 Subject 3 Recovery, Evacuation, Charging v1.2

23. Charging the System Assumptions for the following slides: Procedure:
System is clean and in a vacuum
Compressor is off
Procedure:
Charge by liquid through high side
Shut off discharge valve when pressures equalize
Start compressor
Finish charging through low side
All blended refrigerants must be charged by liquid
© 2004 Refrigeration Training Services - R1 Subject 3 Recovery, Evacuation, Charging v1.2

24. Charge liquid through high side
Charge System
Open tank valve
Refrigerant tank
Charge liquid through high side
Compressor is OFF
404A
Purge hose
Use refrigerant scale
Scales
CONDENSER
Compressor
EVAPORATOR
TEV
Sight Glass
Receiver
Filter-Drier
© 2004 Refrigeration Training Services - R1 Subject 3 Recovery, Evacuation, Charging v1.2

25. Charge System 404A Start compressor Close off high side valve
Open low side valve and charge by liquid
Monitor compressor amps while charging liquid
Monitor head pressure
Scales
System now charged to “present conditions” on TEV system
CONDENSER
Compressor
Note: Refer to manufacturer’s manual for proper charging of critically charged systems and units with flooded condensers
EVAPORATOR
Check sight glass
TEV
Sight Glass
Receiver
Filter-Drier
© 2004 Refrigeration Training Services - R1 Subject 3 Recovery, Evacuation, Charging v1.2

26. Removing Gauges
While the unit is running, return as much refrigerant to the system as possible:
Bleed the high pressure in the hoses
To the low pressure side of the unit
© 2004 Refrigeration Training Services - R1 Subject 3 Recovery, Evacuation, Charging v1.2

27. Remove Gauges Properly
Shut off tank
while unit is running
404A
Purge high side vapor into low side
Open high side valve
Now, remove gauges
Scales
Back seat suction valve
Back seat discharge valve
CONDENSER
Compressor
EVAPORATOR
TEV
Sight Glass
Receiver
Filter-Drier
© 2004 Refrigeration Training Services - R1 Subject 3 Recovery, Evacuation, Charging v1.2

28. End of Recovery, Evacuation, Charging
© 2004 Refrigeration Training Services - R1 Subject 3 Recovery, Evacuation, Charging v1.2