HVAC School - For Techs, By Techs Bryan Orr

In this episode of the HVAC School podcast, Bryan interviews Pat Ward, an HVAC technician who specializes in servicing and maintaining computer room air conditioning (CRAC) units for data centers. They dive deep into the unique challenges and setups involved in cooling these critical facilities.
Pat provides an overview of data centers, explaining that they are essentially industrial-scale computer rooms that generate immense amounts of heat from the servers and need precise environmental controls. CRAC units are specialized air conditioning systems designed to maintain the temperature and humidity within tight parameters suitable for electronic equipment.
Unlike typical comfort cooling, CRAC units supply air around 70°F to avoid excessive dehumidification. Humidity control is crucial, often requiring supplemental humidifiers or dehumidifiers. Pat discusses common configurations like air-cooled direct expansion (DX) units as well as chilled water systems with computer room air handlers (CRAHs). Redundancy is a major consideration, with units networked together to stage capacity and provide backup.
The conversation covers many other topics related to data center cooling such as:
Using economizers and free cooling with outdoor air when conditions allow Potential issues with mildly flammable refrigerants in these applications Typical maintenance tasks like coil cleaning, filter changes, and refrigerant checks Accessing and navigating the control systems which often require passwords Advice for technicians new to working on CRAC units, like studying the equipment layout The massive scale of large data center installations with arrays of 20+ CRAC units Causes of overheating and how to avoid them Growth opportunities in the CRAC niche of HVAC  
Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool. 
Purchase your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium.

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In Part 2 of the Rack Refrigeration Class at Kalos Services, Matthew Taylor discusses safeties, service, and more. Part 1 focuses more on the basic refrigeration circuit of a rack refrigeration system.
When safeties are piped together, we have to keep in mind that they're a bit more complex than most HVAC refrigeration systems, especially when it comes to the oil side. All of these safeties and their proper installation can be located on the wiring diagrams. Safeties often respond to pressure, both in the refrigerant circuit and the oil circuit, but they may also respond to amperage or temperature.
Each compressor on a rack has its own safety controls, but all compressor safeties should be wired in series. Overloads may measure temperature or amperage and break the circuit if it detects unsafe conditions. We also deploy demand cooling strategies to cool the compressor and help control compression ratios. We can also control capacity with staging strategies. Mechanical controls may be able to communicate with electronic controllers, but these cases are less common in conventional rack systems. 
Matthew also covers:
Pop-offs and high-pressure switches Overloads and misdiagnosed compressor failures Sentronic oil pressure controls Mechanical and electronic controls Adjusting metering devices Liquid and vapor injection Subcooling and interstage cooling Suction filters and when to use them Service valves, hoses, and depressing Schrader cores for checking charge Restrictions in the refrigerant circuit Accumulators Pressure transducers and troubleshooting Mechanical and electronic time delays Bypassing safeties in mission-critical applications Compressor staging and unloaders  
Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool. 
Purchase your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium.

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Check out our handy calculators here or on the HVAC School Mobile App for Apple and Android.

This episode dives into an interesting and pragmatic discussion about how HVAC contractors can better balance their workload throughout the year. Kevin from Haven shares insights from observing HVAC businesses across the country and how some are taking a more strategic approach to triaging work.
The main idea is to get systems up and running in the peak summer months when demand is highest, while also collecting data and making notes for more in-depth commissioning, ductwork upgrades, IAQ improvements, etc. that can be tackled in the fall "shoulder season." The hosts discuss the market forces that drive the typical reactive cycle - consumers waiting until systems fail to call for service, companies prioritizing new equipment installs when demand is high to boost revenue, etc.
However, they propose a model where contractors are more proactive about maintenance, communication, and expectation-setting. Install the right-sized equipment over the summer, document issues to revisit later, use data loggers to analyze system performance, and then circle back in fall/winter for comprehensive commissioning when there is more availability. This allows delivering better quality work while smoothing workload across more months.
The episode covers several key points and considerations, including:
Prioritizing load calculation and properly sizing equipment upfront Deploying IAQ monitors to identify issues like humidity control Offering full-scope solutions and letting customers decline unneeded services Shifting technician roles seasonally between installs and commissioning Developing standard workflows and checklists for each phase Potential business benefits like retention by providing growth opportunities Overall, it presents a balanced, practical approach for HVAC businesses to improve quality, reduce stress during peak seasons, and keep technicians engaged through varied work. As Kevin notes, it's a model more contractors could adopt with training and open-sourced best practices.
 
If you are interested in the workflows discussed in the podcast, you can become a HAVEN pro today at https://pro.haveniaq.com/. You can also email Bryan about summer triage strategies at bryan@hvacrschool.com.  
Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool. 
Purchase your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium.

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Check out our handy calculators here or on the HVAC School Mobile App for Apple and Android.

In this insightful episode of the HVAC School Podcast, Ty Brannaman, an exceptional educator and trainer, shares his unique approach to making learning not just effective but also engaging and memorable. He delves into the art of connecting with students, unlocking their curiosity, and fostering a love for learning.
Ty emphasizes the importance of understanding that not all students learn in the same way. He advocates for finding creative ways to capture their attention and spark their interest, whether through hands-on experiments, relatable analogies, or thought-provoking demonstrations. By tapping into students' existing experiences and curiosities, Ty creates an environment where learning becomes an exciting adventure rather than a chore.
One of the key takeaways from the conversation is the power of the Socratic method. Ty encourages educators to ask questions that challenge students' assumptions and encourage them to think critically about the subject matter. By fostering a sense of exploration and discovery, students become active participants in their own learning process, leading to deeper understanding and retention.
Topics Covered:
·        Igniting curiosity and making learning engaging
·        Utilizing everyday objects and relatable analogies to explain complex concepts
·        The Socratic method: Encouraging critical thinking through questioning
·        Creating emotional connections through humor, surprise, and joy
·        Overcoming frustrations and challenges in the teaching process
·        Building a supportive community of educators and learners
·        Embracing mistakes and seeing them as opportunities for growth
·        Finding creative ways to connect with different learning styles
·        The importance of patience and perseverance in the teaching journey
Overall, this podcast episode offers valuable insights for educators, trainers, and anyone passionate about fostering a love for learning. Ty's infectious enthusiasm and creative approach serve as a reminder that education can be a transformative and rewarding experience when approached with empathy, creativity, and a genuine desire to ignite the spark of curiosity in every learner.
 
Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool. 

Purchase your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium.

Subscribe to our podcast on your iPhone or Android.  

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Check out our handy calculators here or on the HVAC School Mobile App for Apple and Android.

This podcast episode is Part 1 of a Kalos class on rack refrigeration given by Matthew Taylor. This first segment focuses on the basic refrigerant circuit and oil management of a parallel rack system, common in market refrigeration.
Parallel racks follow the same general process as any other compression refrigeration system. However, they contain multiple compressors on a single rack. These systems have multiple suction lines that tie into one single suction header that feeds into multiple compressors. The suction side of the piping is usually a long distance with varying elevations; risers are vertical stretches of piping that carry oil and refrigerant up and pose a challenge for oil return.
The compressor takes low-pressure vapor on the suction side and turns it into high-pressure vapor on the discharge side. From there, the condenser rejects heat from the refrigerant, which brings the superheated vapor down to saturation temperature and further rejects heat to make the refrigerant fully liquid (subcooled). Metering devices drop the pressure of the refrigerant, and the cases contain evaporators that absorb heat and boil off refrigerant, which travels to the compressors via the suction lines.
Parallel racks come in multiple varieties, but the ones in this podcast are of the direct expansion (DX) variety. Saturation remains a critical principle in these systems: superheat, subcooling, and the pressure-temperature relationship all drive system operation. 
Matthew also covers:
Different types of rack refrigeration systems Customized variations between racks  Looking up case information and reading legends Oil return and controlling velocity Mechanical subcooling Full load amps (FLA) and locked rotor amps (LRA) Temperature glide: dew point, bubble point, and midpoint EPR installation Evaporator efficiency and superheat Compressor types Compression ratio and liquid or vapor injection Oil management components and controls  
Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool. 

Purchase your virtual tickets for the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24. 

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Standard 310 is a technical workflow created by ACCA, ResNet, and ANSI for grading the installation of HVAC systems, typically in new home construction. It plays a crucial role in obtaining Energy Star certification, which can qualify homeowners for tax credits under the Inflation Reduction Act. The five steps of Standard 310 are design review, duct leakage test, total system airflow, blower fan watt draw, and refrigerant charge verification.
In this podcast episode, host Bryan Orr is joined by guests Chris Hughes and Eric Kaiser to discuss Standard 310 and its implications for HVAC contractors.
The standard aims to ensure that HVAC systems are installed correctly and operate as designed. The process involves a third-party HERS rater conducting various tests and measurements, which contractors need to be prepared for. Proper duct sealing, airflow settings, and refrigerant charging are critical for passing the assessments.
One of the challenging aspects highlighted is the refrigerant charge verification step. The standard requires either non-invasive testing (which has temperature limitations) or weigh-in verification with geotagged photos. Chris Hughes suggests manufacturers could develop more consistent commissioning protocols to streamline this process.
Topics covered in the podcast:
Overview of Standard 310 and its five steps Importance for Energy Star certification and tax credits Role of HERS raters and HVAC contractors Duct leakage testing and proper sealing Airflow measurement methods Blower fan watt draw challenges Refrigerant charge verification options Need for consistent commissioning protocols Coordination and documentation required Future improvements to the standard  
Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool. 

Purchase your virtual tickets for the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24. 

Subscribe to our podcast on your iPhone or Android.  

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Check out our handy calculators here or on the HVAC School Mobile App for Apple and Android.