FIXTURE TEMPERATURE
SYSTEM/CIRC CAPACITY (Btu/H) COMPRESSOR OR Manufacterer CONDENSING UNIT Model #
Serial # Manufacterer CONDENSER Model # Design TD Manufacterer RECEIVER Model # PRV Model# Rating HEAD PRESSURE Manufacterer CONTROL Model # & Size EVAPORATOR PRESSURE Manufacterer REGULATING VALVE Model # & Size DISCHARGE BYPASS Manufacterer VALVE Model # & Size HOT GAS Manufacterer SOLONOID VALVE Model # & Size CRANKCASE PRESSURE Manufacterer REGULATING VALVE Model # & Size LIQUID LINE Manufacterer SOLONOID VALVE Model # & Size HIGH/LOW PRESSURE Manufacterer CONTROL Model # & Size FILTER/DRIER Manufacterer
Model # & Size EXPANSION VALVE Manufacterer
Model # & Size Manufacterer EVAPORATOR Model #
Circuits Distributor/nozzle
(Size & Length) LINE SIZING Suction Line (horiz)
Suction Line (riser) Liquid Line
______________________________________________________________________________________________________________________________
R-12 Systems – General Considerations R-12 and R-500 Air Conditioning
1. For centrifugal compressors it is recommended that the maufacturer’s engineering staff become involved in the project – special parts or procedures may be required. This will ensure proper capacity and reliable operation after the retrofit.
2. Most older, direct expansion systems can be retrofit to R-401A, R-409A, R-414B or R-416A (R-500 to R-401B or R-409A), so long as there are no components that will cause
fractionation within the system to occur.
3. Filter driers should be changed at the time of conversion.
4. System should be properly labelled with refrigerant and lubricant type. R-12 Medium / High Temperature Refrigeration (>0F evap)
1. See Recommendation Table for blends that work better in high ambient heat conditions. 2. Review the properties of the new refrigerant you will use, and compare them to R-12.
Prepare for any adjustments to system components based on pressure difference or temperature glide.
3. Filter driers should be changed at the time of conversion.
4. System should be properly labelled with refrigerant and lubricant type. R-12 Low Temperature Refrigeration (<20F evap)
1. See Recommendation Table for blends that have better low temperature capacity. 2. Review the properties of the new refrigerant you will use, and compare them to R-12.
Prepare for any adjustments to system components based on pressure difference or temperature glide.
3. Filter driers should be changed at the time of conversion.
4. System should be properly labelled with refrigerant and lubricant type.
Recommendations for R-12 Retrofit Products
Closest Match/Easiest
R-12 small equipment R-12 larger equipment
R-12 AC R-500 AC Higher T Lower T Higher T Lower T
R-414B R-409A R-414B R-409A R-414B R-409A
R-416A R-401B R-416A R-401A R-409A R-401A
R-401A R-401A R-401A R-414B R-401A R-414B
R-409A R-414B R-409A R-416A R-416A R-416A
R-134a R-134a R-134a R-134a R-134a R-134a
R-416A
Poorest Match/Most Difficult
______________________________________________________________________________________________________________________________
General Retrofit Procedure: Centrifugal, Reciprocating AC and Refrigeration Systems
1. If the system is able to run – collect system data and operating conditions prior to retrofit. 2. Isolate the compressor and recover the R-12. Change the lubricant in the compressor to
polyol ester (POE). For hermetic compressors this may require removal of the compressor. 3. Replace any oil in auxilliary components such as oil separators or oil feed systems.
4. Close the system and run with R-12 for 24 hours to circulate the POE and flush the mineral oil back to the compressor.
5. Repeat steps 1-4 until residual mineral oil level is below 5%. (If the unit is not operational then perform the oil flushing procedure immediately after startup with R-134a.)
6. Recover the R-12 from the entire system.
7. Perform any maintenance, repair or component replacements, and change filter/driers. 8. Evacuate the system to manufacturer’s specifications.
9. Charge the system with the proper amount of R-134a (usually 85% to 90% of the original R-12 charge by weight).
10. Operate the system and record new system operation data. Make adjustments to controls as needed to ensure proper operation.
11. Label the system with the new refrigerant and lubricant type.
Most Common Areas that Require Adjustment or Attention:
• Changing the lubricant to POE
• TXV valve adjustment / superheat setting
______________________________________________________________________________________________________________________________
General Retrofit Procedure: Reciprocating AC and Refrigeration Systems
1. If the system is able to run – collect system data and operating conditions prior to retrofit. 2. Recover the R-12 from the entire system.
3. Perform any maintenance, repair or component replacements, and change filter/driers. If needed (for low temperatures) remove mineral oil from the system and replace with an equivalent amount of alkylbenzene oil.
4. Evacuate the system to manufacturer’s specifications.
5. Charge the system with the proper amount of the blend (usually 80% to 85% of the original R-12 charge by weight). Be sure to remove liquid refrigerant from the cylinder to get the proper composition (but flash the refrigerant before feeding into a running system).
6. Operate the system and record new system operation data. Make adjustments to controls as needed to ensure proper operation.
7. Label the system with the new refrigerant and lubricant type.
Most Common Areas that Require Adjustment or Attention:
• TXV valve adjustment / superheat setting (use Vapor side of PT chart)
• Pressure controls (cut in / cut out)
• Pressure related switches or controls – difference from R-12 pressures
• Irregular frost formation with high glide blends
• High discharge pressure or temperature, high amps in high ambient temperature
conditions (abuse of compressor)
______________________________________________________________________________________________________________________________
General Retrofit Procedure: Reciprocating AC and Refrigeration Systems
1. If the system is able to run – collect system data and operating conditions prior to retrofit. 2. Recover the R-12 from the entire system.
3. Perform any maintenance, repair or component replacements, and change filter/driers. If needed (for complicated piping, large hold-up volumes) remove mineral oil from the system and replace with an equivalent amount of polyol ester lubricant.
4. Evacuate the system to manufacturer’s specifications.
5. Charge the system with the proper amount of the blend (usually 80% to 85% of the original R-12 charge by weight). Be sure to remove liquid refrigerant from the cylinder to get the proper composition (but flash the refrigerant before feeding into a running system).
6. Operate the system and record new system operation data. Make adjustments to controls as needed to ensure proper operation.
7. Label the system with the new refrigerant and lubricant type.
Most Common Areas that Require Adjustment or Attention:
• TXV valve adjustment / superheat setting (use Vapor side of PT chart)
• Pressure controls (cut in / cut out)
• Pressure related switches or controls – lower than R-12 pressures
• Loss of capacity at lower evaporator temperatures / longer run times
______________________________________________________________________________________________________________________________
General Retrofit Procedure: AC and Refrigeration Systems
1. If the system is able to run – collect system data and operating conditions prior to retrofit. 2. If an oil change is indicated (R-407C, possible R-417A), isolate the compressor and
recover the R-22. Change the lubricant in the compressor to polyol ester (POE). For hermetic compressors this may require removal of the compressor.
3. Replace any oil in auxilliary components such as oil separators or oil feed systems.
4. Close the system and run with R-22 for 24 hours to circulate the POE and flush the mineral oil back to the compressor.
5. Repeat steps 1-4 until residual mineral oil level is below 5%. (If the unit is not operational then perform the oil flushing procedure immediately after startup.
6. Recover the R-22 from the entire system.
7. Perform any maintenance, repair or component replacements, and change filter/driers. 8. Evacuate the system to manufacturer’s specifications.
9. Charge the system with the proper amount of the blend (usually 85% to 95% of the original R-22 charge by weight). Be sure to remove liquid refrigerant from the cylinder to get the proper composition (but flash the refrigerant before feeding into a running system).
10. Operate the system and record new system operation data. Make adjustments to controls as needed to ensure proper operation.
11. Label the system with the new refrigerant and lubricant type.
Most Common Areas that Require Adjustment or Attention:
• TXV valve adjustment / superheat setting (use Vapor side of PT chart)
• Pressure controls (cut in / cut out)
• Pressure related switches or controls – difference from R-22 pressures
• Irregular frost formation with high glide blends
• Changing the lubricant to POE
______________________________________________________________________________________________________________________________
General Retrofit Procedure: Reciprocating AC and Transport Refrigeration Systems
1. If the system is able to run – collect system data and operating conditions prior to retrofit. 2. Recover the R-500 from the entire system.
3. Perform any maintenance, repair or component replacements, and change filter/driers. If needed (for low temperatures) remove mineral oil from the system and replace with an equivalent amount of alkylbenzene oil.
4. Evacuate the system to manufacturer’s specifications.
5. Charge the system with the proper amount of the blend (usually 85% to 90% of the original R-500 charge by weight). Be sure to remove liquid refrigerant from the cylinder to get the proper composition (but flash the refrigerant before feeding into a running system).
6. Operate the system and record new system operation data. Make adjustments to controls as needed to ensure proper operation.
7. Label the system with the new refrigerant and lubricant type.
Most Common Areas that Require Adjustment or Attention:
• TXV valve adjustment / superheat setting (use Vapor side of PT chart)
• Pressure related switches or controls – most have lower pressure than R-500
______________________________________________________________________________________________________________________________
General Retrofit Procedure: Refrigeration Systems and Ice Machines
1. If the system is able to run – collect system data and operating conditions prior to retrofit. 2. Recover the R-502 from the entire system.
3. Perform any maintenance, repair or component replacements, and change filter/driers. If oil return has been a problem with R-502, remove mineral oil from the system and replace with an equivalent amount of alkylbenzene oil.
4. Evacuate the system to manufacturer’s specifications.
5. Charge the system with the proper amount of the blend (usually 80% to 85% of the original R-502 charge by weight). Be sure to remove liquid refrigerant from the cylinder to get the proper composition (but flash the refrigerant before feeding into a running system).
6. Operate the system and record new system operation data. Make adjustments to controls as needed to ensure proper operation.
7. Label the system with the new refrigerant and lubricant type.
Most Common Areas that Require Adjustment or Attention:
• TXV valve adjustment / superheat setting (use Vapor side of PT chart)
• Pressure controls (cut in / cut out)
• Pressure related switches or controls – difference from R-502 pressures