Refrigerant Piping Design Guide
Introduction.3 Audience.3 Using This Manual.3 Refrigerant Piping.4 Refrigerant Piping Design Check List.5. Piping Design Basics.9 Liquid Lines.10 Suction Lines.12 Discharge Lines.13 Multiple Refrigeration Circuits.16. Sizing Refrigerant Lines.18 Refrigerant Capacity T ables.18 Equivalent Length for Refrigerant Lines.18 Refrigerant Oil.22 Suction Line Sizing.22 Oil Return in Suction and Discharge Risers.23. Installation Details.40 Pump Down.40 Piping Insulation.40 Refrigerant Line Installation.41. Condenser Flood Back Design.42 Safety and the Environment.44 Appendix 1 - Glossary.45 Appendix 2 u2013 Refrigerant Piping T ables (Inch-Pound).49 Appendix 3 u2013 Refrigerant Piping T ables (SI).70.
Proper Refrigeration Piping Installation Practices – Installing a new air conditioning and heating system requires skill and knowledge of proper procedures in electrical wiring, controls wiring, and pipework. On commercial projects a skilled electrician handles the electrical hookups, a controls technician handles the control wiring, and a pipefitter handles the pipework including the refrigeration piping which can include chilled water and refrigeration pipework. Proper Refrigeration Piping Installation Practices - Installation Factors and Considerations In residential installations, two or three skilled HVAC technicians usually handle the complete installation except for running line voltage from a breaker panel to the air handler and the outdoor unit. By code that requires an electrician and an electrical permit (In many municipalities however code requirements vary).
It is important that all the work be done correctly according to code and best industry practices following basic fundamentals. This is very important in many regards including correct installation, the finished job looking professional, and the reliability of the system for its operating life. This requires a skilled knowledgeable technician that can wear many different hats to get the job done right. If the refrigerants mix between the two systems then it will cause the compressor to fail prematurely. One system uses a natural oil and the other system uses a synthetic oil. When the oil mixes it will create a toxic sludge that is very bad for the compressor. It is possible to reuse the old refrigerant pipe and possibly an old R-22 evaporator coil with a new R-410A condenser (if the coil/piping size matches the capacity and technical requirements) but the system needs to be flushed thoroughly.
The flush needs to rid the old pipe and/or evaporator coil of all residual oil or other contaminants left in the old piping. Recommendations for the Old Piping Replacement Recommendations are that the old system is completely replaced simply to prevent cross contamination and failure of the new system.
It is best to be safe than sorry later. It will cost more to replace everything but the cost of replacing a new compressor that failed prematurely due to cross contamination is more costly than simply replacing everything in most cases and among other costs. Replace the refrigerant pipe and the evaporator when retrofitting R-410A with an old R-22 system. Protection of Refrigerant Piping in Wall Penetration is is Essential This provides insurance by keeping all foreign matter out of the piping. Additionally, it will save you much time and money later. Take zero risk on contaminating the refrigeration piping with foreign debris or worse, moisture. Before brazing the pipe it is not a bad idea to go ahead and blow the pipe out with a nitrogen purge just to make sure nothing got in the pipe.
Tube Size and Component Selection. Design of the HVAC system is the prerogative and. This application guide provides refrigerant piping guidelines for. Refrigerant Piping Design Goals A common goal is to size the Suction, Hot Gas and Liquid. 1967 ASHRAE Guide and Data Book {{ Maximum allowable hanger distance.
Using installation practices like this can and will save time, effort, and money in the future. Clean System Protected from Atmosphere During Installation Proper Refrigeration Piping Installation Practices - Ensuring that new system is clean and free of debris especially in the piping. When finished always use caps or plugs on any piping exposed to the atmosphere. Keeping trash and moisture out of the system is very important and will save time later on when the system is permanently sealed and ready for evacuation procedures.
Using nitrogen flow to prevent oxidation will also keep the piping clean and free of contaminants. Technical Details for Longer Runs Proper Refrigeration Piping Installation Practices - If running the refrigerant pipe for an extended distance keep refrigerant pipe within the manufacturers recommended limits. Always keep in mind the risers and possible pressure drop in the refrigerant piping based on total equivalent length (TEL). Oil traps should be used as recommended by the manufacturer. Keeping liquid refrigerant from reaching the compressor is essential to protecting the compressor especially reciprocating compressors. Proper refrigerant pipe is essential and recommended by the manufacture.
Refrigerant pipe sizing charts are available in the installation instructions. All these things must be factored into the design and proper installation of refrigerant pipe work. Home Runs When Possible - Avoiding Unnecessary Solder Joints Avoid solder joints when necessary using home run piping from the condenser to the evaporator when possible. After brazing is complete proper refrigerant pipe evacuation and pressure testing is necessary. This is done to purge all non-condensing gasses/moisture from the refrigerant piping.
Dry nitrogen should be used for the pressure testing and purging and then a proper vacuum of the system should be done. Pressure testing includes a test that the system will hold a charge of nitrogen (300 to 400 p.s.i.g but follow manufacturers instructions for maximum pressure testing limitations - remember the evaporator coil pressure limitations also) for at least 15 minutes and the same with the vacuum pressure testing. Line Set Runs Neatly Up the Side of the House to the Attic Air Handler A micron gauge should be used and a 500-micron vacuum should be held for at least 15 minutes with the refrigerant piping system in a vacuum. Proper pressure testing ensures no leaks in the refrigerant piping or the evaporator coil. It tests any and all connections between the condenser and the evaporator coil. When the refrigerant piping is pressurized with dry nitrogen it is good practice to inspect all the solder joints. Additionally, any other connections.
Check connections such as metering devices, filter-driers, solenoid valves, and flare connections with soap bubbles to ensure integrity of the refrigerant piping. For best practice in evacuating the piping system follow the instructions for a. It may take a little more time and a little nitrogen but will save in headaches later.
Refrigerant Charging Methods Proper charging methods need to be used when charging the system. Most condensers come pre-charged with enough refrigerant with enough refrigerant for the condenser and a refrigerant line set of 25 feet. Other condensers come pre-charged with dry nitrogen and have weigh charge instructions with the new unit. The weigh in instructions should be followed and additionally should be done to make sure the final charge is correct. Additionally some manufacturers also include a for various outdoor ambient temperatures and indoor load temperatures.
It doesn’t hurt to use all the tools available to ensure the system is properly charged. Many HVAC companies use senior HVAC technicians to perform start up of any new installations. The final sign off on the finished installation is this senior HVAC technician.
Carrier Refrigerant Piping Design
He goes over the final installation with a fine-toothed comb to make sure everything is correctly installed and operating as designed. Piping Materials and Material Quality Proper Refrigeration Piping Installation Practices - Finally, make sure to use all the proper and rated materials for the installation. Silver solder for brazing and only piping for refrigeration should be used.
When in doubt about any technical details, installation methods, or quality and rating of materials always call the technical representative for the manufacturer. Proper Refrigeration Piping Installation Practices - Conclusion for Proper Installation and Design Practices By following all the fundamentals and doing quality work the new installation will have reliability. And keep working reliably for years to come. Proper installation also ensures you will get the efficiency the unit is rated for by the manufacturer. Another reason why it is recommended to hire qualified HVAC contractors when purchasing and installing new equipment.
Refrigerant Piping Design Guide
High Performance HVAC Proper Refrigeration Piping Installation Practices. HVAC Random Tip BoxHVAC Tip - Ceiling Fans Save Energy: Ceiling fans installed strategically in your home or business can save you in air conditioning energy costs in the summer. The draft effect from the fan will allow you to raise the thermostat setting by up to 4 degrees and still remain comfortable. Make sure you purchase ceiling fans with energy efficient motors and blade designs. Some ceiling fans have inefficient motors and bad blade designs that will reduce the energy savings you can realize. A qualified electrician can install ceiling fans in your home or business and you can enjoy the savings and compliment your HVAC system.