APPLICATION & SERVICE GUIDE HFC Refrigerant R410a Used In GeoMax2 Geothermal Heat Pump Systems
R410a Application and Service Guide Although the bulk of this manual is information regarding R410a, R407c will also be discussed for purposes of comparison and since it is one of the socalled new refrigerants. R410a Overview R410a is a non-chlorine based (HFC) refrigerant, that with R407c and R134a, is seen as the future of all refrigerants used worldwide.
R410a Application and Service Guide Table 2. R410a Pressure/Temperature Chart R410a T Temperature Pressure °F -15 -10 -5 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 145 150 psig 31.3 36.5 42.2 48.4 55.1 62.4 70.2 78.5 87.5 97.2 107.5 118.5 130.2 142.7 156.0 170.1 185.1 201.0 271.8 235.6 254.5 274.3 295.3 317.4 340.6 365.1 390.9 418.0 446.5 476.5 508.0 541.2 576.0 612.
R410a Application and Service Guide Figure 1. PPM of Water Absorbed Over Time POE: Continues to absorb moisture PPM of W Water used in R410a systems. Older R22 leak detectors and Halide torch leak detectors can not be used in R410a service. NEVER use a mixture of air and R410a to leak check. The mixture may become flammable at pressures above amtospheric. Nitrogen and trace R410a or nitrogen alone can be safely used for leak testing in R410a systems.
R410a Application and Service Guide • 35% annual leak rate of commercial and industrial refrigeration • 15% annual leak rate comfort cooling chillers and all other equipment R407c Considerations R407c equipment for leak detection are the same as R410a. However, the technician CANNOT use the existing refrigerant in the system after leaks have occurred. There can be a significant change in the refrigerant composition during multiple leaks and recharges.
R410a Application and Service Guide An overcharged TXV unit can be identified by: • A throttling valve (Figure 3) to ensure the liquid vaporizes as it enters the suction line of the unit. • High subcooling • Τhe gauge set valve as a throttling device to restrict liquid from flooding the compressor during charging. • High head pressures Even though R410a has a very small fractionation potential it cannot be ignored completely when charging.
R410a Application and Service Guide 4. Measure the suction line temperature just prior to entering the compressor. 5. Subtract the saturation temperature from the suction temperature to find the superheat. Consult Table 4 for appropriate values. 6. If the superheat is too high then unit might still be undercharged. TXV's will mask overcharging in the superheat value by closing off the TXV port and reducing the refrigerant flow. Therefore superheat CANNOT be used to identify an overcharged unit.
SAFETY AND HANDLING OVERVIEW ASHRAE Standard 15 details safety precautions when handling refrigerants in commercial systems and should be read and understood. Refrigerants are especially dangerous in confined spaces. • R410a has a much higher pressure (+60%) associated with its operation. Use caution when handling and ensure proper tools and equipment. • Use an R410a approved recovery device. Recovery cylinders must have a service pressure rating of 400 psig (DOT 4BA 400 and DOT 4BW 400 are acceptable).
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