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 pipe work. On commercial projects a skilled electrician handles the electrical hook ups, a controls technician handles the control wiring, and a pipe fitter handles the pipe work including the refrigeration piping which can include chilled water and refrigeration pipe work.
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.
Proper Refrigeration Piping Installation Practices – R-22 to R-410A Retrofit Factors and Considerations
When manufacturers began selling the newer R-410A refrigerant in air conditioners and heat pumps, because of government regulations, it forced HVAC contractors and homeowners to not only replace the condenser when the condenser failed but also the indoor evaporator coil. The reason for this is because the old R-22 refrigerant coil and the newer R-410A refrigerant will not work together.
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.
The bottom line is if you are doing a retrofit and using a different refrigerant than was in the old unit either replace the entire line set or flush the old line set if you are reusing it. Additionally, always be very vigilant about protecting the pipes from accidental debris getting into the pipe. Cover all pipe openings with tape, caps or plug the pipe opening with a rubber plug until you are ready to braze the ends.
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. Using installation practices like this can and will save time, effort, and money in the future.
Proper Refrigeration Piping Installation Practices - Other fundamentals for refrigerant pipe design and installation include:
Local/Other Related Refrigerant Piping Codes
Clean System Protected from Atmosphere During Installation
Technical Details for Longer Runs
Refrigerant Piping Valves
Home Runs When Possible - Avoiding Unnecessary Solder Joints
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 triple evacuation. It may take a little more time and a little nitrogen but will save in headaches later.
Refrigerant Charging Methods
Additionally some manufacturers also include a pressure temperature chart 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. 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 - 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.
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Proper Refrigeration Piping Installation Practices