 Nathan Orr is back. In this podcast, we discuss suction pressure in market refrigeration and how rack techs think about it differently than HVAC. On parallel rack systems, suction temperature helps technicians determine the cooling load and how to get that to temperature. You run your discharge air temperature a bit lower than the product temperature. Your suction pressure also lets you know if your coil is reaching the correct temperature. Coil temp, also called suction saturation temperature (SST), is a vital metric for rack system operation. Lower suction pressure indicates a lower coil temperature or SST. The evaporator pressure regulating valves help control the evaporator pressure to manipulate the evaporator temperature. Compressors also help drive suction pressure, which is critical because racks may have several of them. When you walk into a rack room, you may see around five compressors. All suction lines tie into a single suction header (same goes for discharge and liquid lines and headers). Typically, the rack is constructed to maintain the SST even if a compressor goes down. When the SST no longer maintains, there will be a "rack down" call. If a case is not keeping temperature without an apparent rack issue, you want to take your superheat at the case to get an idea of the suction. The superheat, SST, and suction pressure will be your key indicators of problems, including defrost issues, clogged TXV strainers, and airflow problems. Overall, rack refrigeration systems work best with high suction pressure and low liquid pressure. Nathan and Bryan also discuss:  TD in rack refrigeration Setting EPR valves Rack sizing "Rack down" calls Troubleshooting produce cases Holdback valves Frozen cases Using dry steam     Learn more about Refrigeration Technologies HERE. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Suction Pressure in Market Refrigeration

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In this insightful podcast episode, the host delves into the crucial aspects of positive and productive client communication, drawing from his extensive experience in the residential air conditioning industry. He emphasizes the importance of setting the right tone, bringing energy, building trust, and adapting to different customer personalities when interacting with clients. The host highlights the key elements of positive communication, such as maintaining a consistently upbeat and enthusiastic demeanor, while also being mindful of the client's preferences. He stresses the importance of active listening, to truly understand the customer's needs and concerns, rather than simply waiting for your turn to speak. The host also touches on the challenges of dealing with difficult customers, such as those who are overly focused on price or technical details, and provides strategies for navigating these situations with patience and professionalism. The discussion then shifts to the productive side of client communication, emphasizing the importance of being clear, precise, and solution-oriented. The host delves into the pitfalls of being a "yes-man" and making promises that are difficult to follow through on, and instead encourages a more assertive and responsible approach. He emphasizes the need to take ownership of one's words and actions, ensuring that any commitments made to the client are followed through with diligence and care. The podcast also touches on the significance of situational awareness, wherein the host encourages technicians and salespeople to adapt their communication style based on the client's background and personality. Whether it's an aerospace engineer, a computer programmer, or a contractor, the host provides insights into how to tailor your approach to best serve each individual client. Key Topics Covered:  Positive communication: Setting the tone, bringing energy, building trust, and adapting to customer personalities Productive communication: Importance of being clear, precise, and solution-oriented Avoiding the "yes-man" trap and taking responsibility for one's words and actions Situational awareness: Adapting communication style based on client background and personality Dealing with difficult customers and navigating challenging conversations The value of honesty and truthfulness in client interactions Importance of initial conversations and following up on commitments made to clients Balancing empathy and professionalism when addressing clients' personal issues or concerns  By addressing these critical aspects of client communication, the podcast provides invaluable insights for professionals in the HVAC industry and beyond, highlighting the key strategies for fostering positive and productive relationships with customers. Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.  Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.” Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.  Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

Positive Productive Client Communication

Roman Baugh, Matthew Condron, and Luke Peterson discuss the importance of proper condensate drain installation and maintenance, particularly in commercial applications. The conversation begins with the hosts examining the typical drain configurations seen in different regional markets, highlighting the significant variations in practices across the country. Sizing and configuration of condensate drains can have a significant impact on system performance, especially in high-static pressure systems. He emphasizes that the "one-size-fits-all" approach of using a 2-inch trap is often insufficient, as the static pressure within the system can overcome the trap's ability to prevent air from being sucked into the drain line. The hosts discuss the chart Roman presents, which provides guidance on selecting the appropriate trap depth based on the static pressure of the system. The discussion then delves into the challenges associated with maintaining condensate drains, including the buildup of debris and the potential for double traps or airlock issues. The hosts share their experiences and best practices for cleaning and troubleshooting drain lines, with a particular focus on the importance of understanding the system's airflow and static pressure characteristics. The conversation also touches on the use of condensate pumps, with the hosts expressing mixed opinions on their effectiveness and the potential for issues, particularly in high-humidity environments. The importance of proper insulation and support for drain lines is also highlighted, as sagging or improper installation can lead to further problems over time. Key Topics Covered:  Typical drain configurations in different regional markets The impact of static pressure on condensate drain performance Proper trap sizing and depth based on system static pressure Challenges with drain line maintenance and troubleshooting The use of condensate pumps and their potential drawbacks Importance of proper insulation and support for drain lines Strategies for cleaning and maintaining condensate drains Relationship between airflow, static pressure, and drain issues Redundant protection methods, such as secondary drain pans and switches Techniques for identifying and addressing air turbulence issues    Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.  Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.” Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.  Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

Condensate Drains Install & Service

In this short podcast episode, Bryan explains electronic expansion valve (EEV) types. EEVs perform the same function as TXVs, but they operate electronically, not mechanically. The EEV makes sure that the evaporator is full of the right amount of refrigerant at saturation; it doesn't just affect evaporator pressure. We don't want high superheat (due to inefficiency), and we don't want zero superheat (due to the risk of compressor failure). EEVs commonly have a stepper motor with a set of discrete settings depending on how many rotations the motor has made. It can be fully open or fully closed, and the number of rotations can set the valve at any value between fully open and fully closed; it's open or closed by a specific percentage. Instead of a bulb and external equalizer, a pressure transducer and temperature sensor report to the controller and give the controller the data it needs to open or close the EEV to maintain a specific superheat. Pulse-width modulation (PWM) allows an EEV to open and close rapidly. Unlike a stepper motor, PWM solenoids make an EEV stay fully open or fully closed for a specific percentage of time. It receives pressure information from a pressure transducer and temperature information from a thermistor or thermocouple.  As with a TXV, you would look at superheat and pressures to make sure the EEVs are operating correctly.   Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.  Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.” Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.  Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

EEV Types - Short #193

This episode of the HVAC School Live Stream covers the key concepts around heat pump efficiency and understanding the coefficient of performance (COP). Eric Kaiser from TruTech Tools and Jim Fultz from White-Rodgers provide valuable insights into how heat pumps operate and how to optimize their performance, especially in colder weather conditions. The discussion begins by exploring the COP of heat pumps and how it compares to the efficiency of electric resistance heat. A COP above 1 means the heat pump is delivering more heat for the same amount of energy input compared to electric resistance heat. Many homeowners mistakenly believe they should switch to emergency heat once the outdoor temperature drops, thinking the heat pump is no longer efficient. However, even at very low outdoor temperatures, a well-designed heat pump can still operate with a COP above 1, making it a more cost-effective heating option than emergency heat. The conversation then delves into the concept of the thermal balance point, which is the outdoor temperature at which the heat pump can no longer meet the heating load of the home. The guests discuss how to calculate this balance point and how to set up controls to optimize the use of the heat pump and any supplemental heating sources, such as electric resistance heat or a gas furnace in a dual-fuel system. They emphasize the importance of proper air distribution and avoiding blowing cold air directly on the occupants, which can be a common complaint with heat pumps. Key Topics Covered:  Coefficient of Performance (COP) and how it compares to electric resistance heat Efficiency of heat pumps at low outdoor temperatures Thermal balance point and how to calculate it Optimizing control settings to balance heat pump and auxiliary heat usage Importance of proper air distribution and avoiding blowing cold air directly on occupants Considerations for dual-fuel systems with both a heat pump and a gas furnace Best practices for programming thermostats and control systems to ensure optimal performance and comfort    Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.  Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.” Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.  Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).  

Heat Pump COP and Low Temp Lock Out

In this short podcast episode, Bryan talks about motor protection types, including overloads. The most common overload we see in residential HVAC is a built-in thermal overload, which is usually a bimetallic disk that flexes in response to heat (such as from a locked condition, electrical problem, or simply running hot) and opens the circuit. The two metals have different expansion and contraction rates, which causes the flexing; they will return to their original position once the motor cools down. In some cases, these can fail when they open and close too often; they are not designed for switching duty. Many circuit breakers have a similar thermal design and may be prone to nuisance tripping in the summer. A lot of commercial motors rely on external overloads; some are even built into the electrical box rather than the compressor. These external magnetic overloads are often integrated into the contactor, which turns the motor on and off; this type of contactor is called a starter. These starters may have adjustable overload settings based on current, not just temperature (which may also respond to nuisance sources of heat and require a cooldown period). Some circuit breakers also trip magnetically and are less likely to be affected by temperature. Thermistor-based overloads usually consist of a PTC (positive temperature coefficient) resistor; as temperature goes up, resistance goes up, which can take a motor winding out of the circuit. NTCs are in separate parallel circuits with relays; as the resistance decreases, it pulls in a coil that opens the circuit.   Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.  Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24. If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.” Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.  Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).

Suction Pressure in Market Refrigeration

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