High Temperature Retrofit from R22 to R407C Application Bulletin 124 Application Bulletin Number: Release EN: Date: Revision EN: Date: 124 C18811 10/20/95 Z27301 10/2/15 Subject: High Temperature Retrofit from R22 to R407C These are only general guidelines and in no way should they replace, contradict or otherwise take precedence over any local, state or federal law or regulation pertaining to the recovery, reclamation, and recycling of refrigerants. With the phase-out of HCFC’s, existing air conditioning/heat pump equipment will need to be replaced with new equipment or retrofitted with new components (including the compressor) that are approved for use with the new refrigerant and their lubricants. Using the procedures described below, existing R22 systems can be retrofitted for use with R407C, allowing them to continue in service for the remainder of their useful life. Bristol Compressors does not recommend the changeover of HCFC refrigerants to HFC’s in systems that are operating and have no leaks. R407C is a zeotropic blend of refrigerants of the following composition: R32 R125 R134a 23% 25% 52% New High Temperature R407C Compressors are identified by the number 7 in the second digit of the model number (example: H75B28QABC). These compressors are factory oil charged with Polyolester (POE) lubricant and employ an improved lubrication system which are required for the new refrigerant . For Bristol’s approved lubricant type and required oil charge amounts for use with R407C, refer to the individual compressor model specification sheet. This information can be found on Bristol’s website www.bristolcompressors.com. The use of any other lubricant may void the compressor warranty. SYSTEM DESIGN 1.0 Refrigerant Metering Devices The performance of each system is very dependent on the proper operation of each metering device. Devices such as solenoid valves, capillary tubes, fixed orifice valves, and expansion valves can perform differently if they are not correctly adjusted or properly sized. For example, the port size of a valve may not be correct for the new refrigerant density. Each valve and metering device manufacturer should be consulted, along with the system's manufacturer, to ensure all components will work properly in the presence of the new refrigerant and lubricant. 2.0 Filters/Driers The proper selection of a system's filter drier is very important. Some filter driers may not be suitable for R407C refrigerant and Polyolester lubricant. Therefore, the original equipment manufacturer should be contacted for the proper filter drier selection. It is important to replace the filter drier any time the refrigerant or lubricant in a system is changed. Specifically, Bristol Compressors requires a new suction Revision Z27301 Application Bulletin 124 Page 2 line filter drier be installed during any compressor replacement. Maintaining good system performance, reliability and cleanliness is closely linked to proper filter drier operation . 3.0 Controls The proper operation of many types of air conditioning/heat pump equipment requires that the control systems function correctly. The control system could be pressure controls, temperature controls, timing devices, or sophisticated electronic controls. Changing to R407C refrigerant and polyol ester lubricant in a system could adversely affect these control systems. Each equipment manufacturer should be consulted to ensure each control system will operate correctly with the R407C refrigerant/polyol ester lubricant combination. Changes most likely will have to be made for continued good equipment performance. These changes could involve adjusting temperature or pressure set points to new values or replacing the control system with a newly designed unit. 4.0 Explanation of R407C vs. R22 Condenser and Evaporator Temperature/Pressure Graphs Pressure versus temperature charts and graphs are included on pages 4 through 8 as a general information guideline. More detailed specific saturated property tables can be obtained from the chemical manufacturer and should be used when conducting system retrofits. The graphs are intended to represent the pressures that R407C delivers versus R22 at the equivalent saturated evaporator and condenser temperatures. 4.1 Explanation of refrigerant glide inherent to R407C 4.1.1 R407C has refrigerant “glide”. Glide is due to the different boiling and condensing temperatures of the three components that make up R407C. This means there is not a one to one relationship between pressure and temperature as with R22. The saturated vapor and saturated liquid values are approximately 10°F apart for a given pressure, whereas with R22 they are one and the same. 4.1.2 The temperature glide of this refrigerant should not cause any problems as long as you keep in mind the following points about the relationship between pressures and temperatures of the evaporator and condenser. a) When specifying the evaporating and condensing temperatures use the mean (or average of dew and bubble point) temperatures. b) When setting evaporator superheat, calculate it from the saturated vapor (or dew point) temperature. c) When setting subcooling, calculate it from the saturated liquid (or bubble point) temperature. 4.1.3 Specific examples: (Some interpolation between values may be required) 4.1.3.1 Revision Z27301 Set conditions to run a 45°F evaporator, 130°F condenser with 20°F superheat and 15° liquid subcooling. a) Find the 45°F mean temperature from Table 1. The pressure corresponding to this mean temperature is your suction pressure = 94.4 psia. b) Calculate the return gas temperature using the dew point temperature at this pressure. Example: 50.59°F + 20°F superheat = 70.59°F return gas temperature. c) Find 130°F mean temperature from Table 1. The pressure corresponding to this mean temperature is your discharge pressure = 339.4 psia. d) Calculate the liquid temperature using the bubble point temperature at this pressure. Example: 126°F - 15°F subcool = 111°F liquid temperature. Application Bulletin 124 Page 3 4.1.3.2 Determine the amount of superheat on a system that measures a suction pressure of 68 psig at the bulb, and the temperature at the bulb reads 52°F. a) Revision Z27301 Convert 68 psig to psia = 68 + 14.7 (atmospheric pressure) = 82.7 psia. Look up the dew point temperature from Table 1 at 82.7 psia. This value is 43.3°F. Your superheat is 52°F - 43.3°F = 8.7°F Application Bulletin 124 Page 4 R407C PRESSURE/TEMPERATURE TABLE Saturated Liquid and Saturated Vapor Properties PSIA PRESSURE PSIG DEW POINT °F MEAN TEMP °F BUBBLE POINT °F 10 -4.7 -47.90 -54.48 -61.06 11 -3.7 -44.64 -51.18 -57.72 12 -2.7 -44.59 -49.61 -54.62 13 -1.7 -38.75 -45.24 -51.72 14 -0.7 -36.07 -42.53 -48.99 15 0.3 -33.53 -39.97 -46.40 16 1.3 -31.13 -37.54 -43.95 17 2.3 -28.84 -35.23 -41.62 18 3.3 -26.65 -33.03 -39.40 19 4.3 -24.56 -30.91 -37.26 20 5.3 -22.55 -28.89 -35.22 21 6.3 -20.62 -26.94 -33.25 22 7.3 -18.76 -25.06 -31.35 23 8.3 -16.96 -23.25 -29.53 24 9.3 -15.23 -21.50 -27.76 25 10.3 -13.55 -19.80 -26.05 26 11.3 -11.92 -18.16 -24.39 27 12.3 -10.34 -16.56 -22.78 28 13.3 -8.0 -15.01 -21.21 29 14.3 -7.31 -13.50 -19.69 30 15.3 -5.85 -12.03 -18.21 31 16.3 -4.44 -10.60 -16.76 32 17.3 -3.05 -9.20 -15.35 33 18.3 -1.70 -7.84 -13.98 34 19.3 -0.38 -6.51 -12.64 35 20.3 0.90 -5.21 -11.32 36 21.3 2.16 -3.94 -10.04 37 22.3 3.40 -2.69 -8.78 38 23.3 4.61 -1.47 -7.55 39 24.3 5.79 -0.28 -6.34 40 25.3 6.95 0.90 -5.16 45 30.3 12.44 6.44 0.43 50 35.3 17.47 11.52 5.57 TABLE 1 Revision Z27301 Application Bulletin 124 Page 5 R407C PRESSURE/TEMPERATURE TABLE (Page 2) PSIA PRESSURE PSIG DEW POINT °F MEAN TEMP °F BUBBLE POINT °F 55 40.3 22.14 16.23 10.32 60 45.3 26.48 20.62 14.76 65 50.3 30.56 24.74 18.92 70 55.3 34.40 28.63 22.85 75 60.3 38.04 32.31 26.57 80 65.3 41.50 35.80 30.10 85 70.3 44.79 39.13 33.47 90 75.3 47.94 42.32 36.69 95 80.3 50.96 45.37 39.78 100 85.3 53.85 48.30 42.75 105 90.3 56.64 51.13 45.61 110 95.3 59.33 53.85 48.37 115 100.3 61.93 56.49 51.04 120 105.3 64.44 59.03 53.62 125 110.3 66.87 61.50 56.12 130 115.3 69.23 63.89 58.54 135 120.3 71.52 66.21 60.90 140 125.3 73.74 68.47 63.19 145 130.3 75.91 70.67 65.42 150 135.3 78.02 72.81 67.59 155 140.3 80.07 74.89 69.71 160 145.3 82.08 76.93 71.78 170 155.3 85.95 80.87 75.78 180 165.3 89.64 84.62 79.60 190 175.3 93.19 88.23 83.27 200 185.3 96.59 91.70 86.80 210 195.3 99.86 95.03 90.20 220 205.3 103.01 98.25 93.48 230 215.3 106.05 101.35 96.65 240 225.3 109.00 104.36 99.71 250 235.3 111.84 107.27 102.69 260 245.3 114.60 110.09 105.58 270 255.3 117.28 112.83 108.38 280 265.3 119.88 115.50 111.11 290 275.3 122.41 118.09 113.77 TABLE 1 Revision Z27301 Application Bulletin 124 Page 6 R407C PRESSURE/TEMPERATURE TABLE (Page 3) PRESSURE PSIA PSIG DEW POINT °F MEAN TEMP °F BUBBLE POINT °F 300 285.3 124.88 120.62 116.36 310 295.3 127.27 123.08 118.89 320 305.3 129.61 125.49 121.36 330 315.3 131.89 127.83 123.77 340 325.3 134.12 130.13 126.13 350 335.3 136.29 132.37 128.44 360 345.3 138.41 134.56 130.70 380 365.3 142.52 138.81 135.09 390 375.3 144.51 140.87 137.22 400 385.3 146.46 142.89 139.31 410 395.3 148.37 144.87 141.37 420 405.3 150.24 146.81 143.38 430 415.3 152.08 148.73 145.37 TABLE 1 Revision Z27301 Application Bulletin 124 Page 7 Saturated Properties HP81 vs. R502 - Pressure vs. Temperature Graph Condenser Temperature vs. Pressure 370 360 350 HP81 340 R502 330 320 310 Pressure (psia) 300 290 280 270 260 250 240 230 220 210 200 190 180 170 160 150 80 90 100 110 120 130 Condenser Temperature (°F) Figure 2 Revision Z27301 Application Bulletin 124 Page 8 Pressure (psia) Evaporator Temperature vs. Pressure 86 84 82 80 78 76 74 72 70 68 66 64 62 60 58 56 54 52 50 48 46 44 42 40 38 36 34 HP81 R502 -10 0 10 Evaporator Temperature (°F) 20 30 Figure 3 Revision Z27301 Application Bulletin 124 Page 9 TABLE 1 Pressure-Temperature Chart Saturated Vapor Temperature °F Pressure (psig) (1) HP81 (1) Saturated Vapor Temperature °F R502 Pressure (psig) HP81(1) R502 0 -49 -50 46 14 15 2 -44 -45 48 16 16 4 -39 -40 50 17 18 6 -35 -36 52 19 20 8 -32 -32 54 20 21 10 -28 -29 56 22 23 12 -25 -25 58 23 24 14 -22 -22 60 25 26 16 -19 -19 62 26 28 18 -16 -16 64 28 29 20 -13 -13 66 29 30 22 -11 -11 68 31 32 24 -8 -8 70 32 33 26 -6 -6 72 33 34 28 -4 -3 74 34 36 30 -1 -1 76 36 37 32 1 1 78 37 38 34 3 3 80 38 40 36 5 5 85 41 43 38 7 7 90 44 46 40 8 9 95 47 49 42 10 11 100 50 51 44 12 13 105 52 54 Saturated Vapor Temperature (Dew Point)--The temperature (at a given pressure) at which the last drop of liquid HP81 has boiled. It is also the temperature (at a given pressure) where condensation begins. Above this temperature (at the same pressure), the refrigerant is superheated vapor. NOTE: For HP81 the mean evaporator temperature where a change of state occurs is approximately 1°F below the saturated vapor temperature. For example, at a saturated vapor temperature of 11°F, the mean evaporator temperature is approximately 10°F. Revision Z27301 Application Bulletin 124 Page 10 5.0 Maximum Continuous Current (MCC) Data Extensive testing of many compressors with the new refrigerant versus the existing refrigerant have been tested at maximum continuous current (MCC) conditions. The MCC does change with a new refrigerant due to the different load the new refrigerant places on the compressor. HP81 refrigerant, for example, increases the heat load on the compressor causing the thermal protector to trip (open) sooner. Therefore, the MCC for HP81 is typically lower than R502. 6.0 Retrofit Process Overview: Retrofit of an existing R502 system with HP81 can be accomplished using service practices and service equipment commonly used by trained mechanics or service contractors in the field. 6.1 The key steps involved in the retrofit are: - Find the reason for the 502 system/compressor failure and correct - Recover R502 charge from system - Replace filter drier with new filter drier compatible with HP81 - Install new compressor - Reconnect system and evacuate - Charge system with HP81 - Start up system and adjust charge and/or controls to achieve desired operation - Label system "Charged with HP81 Refrigerant" 6.2 Equipment and supplies needed for retrofit: (Refer to refrigerant manufacturer guidelines) - Safety equipment - Refrigeration manifold gauges - Thermocouples - Vacuum pump - Leak detection equipment - Scale - Recovery unit - Recovery cylinder - Replacement refrigerant - Replacement/approved filter drier 6.3 Remove R502 Charge: R502 should be removed from the system and collected in a recovery cylinder using a recovery device capable of pulling 10-20 in. Hg vacuum. If the recommended R502 charge for the system is not known, weigh the amount of refrigerant removed, as the initial quantity of HP81 to be charged into the system will be determined from this figure. 6.4 Replace Filter Drier: It is recommended to replace the filter drier following system maintenance. Consult the filter drier manufacturer for their recommended filter drier to use with HP81. Currently, ALCO's ADK and Sporlan's Catch-All solid core driers are acceptable with HP81. Others may also be acceptable; again, consult the manufacturer. 6.5 Reconnect System and Evacuate: Use normal service practices. To remove air or other noncondensables in the system, it is recommended that the system be evacuated to 200 microns. 6.6 Leak Check System: Use normal service practices. Evacuate system following leak check with any gas. 6.7 Charge System with HP81: HP81 is a near-azeotropic mixture; therefore, the vapor composition in the cylinder is different from the liquid composition. To ensure that the proper refrigerant composition is charged in the system, it is important that liquid only be removed from the charging cylinder. Cylinders of HP81 are equipped with dip tubes, allowing liquid to be removed from the cylinder when the cylinder is in the upright position. The proper position is indicated by arrows on the cylinder and cylinder box. Once removed from the cylinder, HP81 can be charged to the system as vapor as long as all of the refrigerant removed from the cylinder is transferred to the system. Revision Z27301 Application Bulletin 124 Page 11 Due to the liquid density difference of HP81 versus R502, the refrigeration system will require less weight of HP81 than R502. The optimum charge will vary depending on the operating conditions, size of the evaporator and condenser, size of receiver (if present), and length of pipe or tubing runs in the system. For most systems, the optimum charge will be 90-95% by weight of the original R502 charge. It is recommended that the system be initially charged with about 90% by weight of the original R502 charge. Add the initial charge to the liquid line of the system with the compressor not running. When the system and cylinder pressures are equal, load the remainder of the refrigerant into the suction line of the system. In this step, the compressor will be running. Some compressors may be damaged if liquid refrigerant enters the suction side of the compressor. Since liquid must be removed from the charging cylinder, it is important to charge the refrigerant slowly into the suction line to allow it to vaporize before it enters the system. A throttling valve may be used to cause the refrigerant to vaporize. 7.0 6.8 Start up System and Adjust Charge: Start up the system and let conditions stabilize. If the system is undercharged, add additional HP81 in small amounts (still removing liquid from the charging cylinder) until the system conditions reach the desired levels. HP81 is more sensitive to charge size than R502. Therefore, system performance will change more quickly if the system is not optimally charged with HP81 and it is important not to overcharge the system (refer to Installation and Service Instructions). 6.9 Label Components and System: After retrofitting the system with HP81, label the system components to identify the type of refrigerant (HP81) and lubricant (3GS Mineral Oil) in the system so that the proper refrigerant and lubricant will be used to service the equipment in the future. Identification labels are available from DuPont. Summary With the phase-out of CFCs, existing refrigeration equipment will need to be replaced with new equipment or retrofitted with alternative refrigerants. Using the procedures described above, existing R502 refrigeration systems can be retrofitted for use with HP81, allowing them to continue in service for the remainder of their useful life. Attached is a Retrofit Checklist (Appendix 1) for HP81 to assist you in the retrofit process and a System Data Sheet (Appendix 2) to record the system operating conditions for your records. Revision Z27301 Application Bulletin 124 Page 12 Appendix 1 Checklist for HP81 Retrofit 1. Consult the original equipment manufacturer of the system components for their recommendation on the following: - Plastics compatibility - Elastomers compatibility - Lubricant (viscosity, manufacturer, additives) - Retrofit procedure to sustain warranty 2. Remove R502 charge from system (need 10-20 in. Hg vacuum to remove charge). Use recovery cylinder --Do not vent to atmosphere-3. Replace filter drier with new drier approved for use with HP81. - Loose fill driers: use XH7 or XH9 desiccant or equivalent - Solid core driers: check with drier manufacturer for recommendation 4. Reconnect system and evacuate with vacuum pump. (Evacuate to 200 microns.) 5. Leak check system. (Re-evacuate system following leak check.) 6. Charge system with HP81. - Initially charge 90% by weight of original equipment manufacturer specified R502 charge. - Amount of refrigerant charged: _________ 7. Start up equipment and adjust charge until desired operating conditions are achieved. - If low in charge, add in increments of 2 - 3% of original R502 charge. - Amount of refrigerant charged: __________ 8. Total refrigerant charged (add 6 and 7): __________ 9. Label components and system for type of refrigerant (HP81) and lubricant (3GS Mineral Oil). 10. Conversion is complete!! Revision Z27301 Application Bulletin 124 Page 13 Revision Z27301 Application Bulletin 124 Page 14 Release EN Number A23707 Release Date 11/5/93 Revisions C24201 Revision Z27301 9/15/95 Z27301 10/2/15 Application Bulletin 124 Page 15