In this short Q&A podcast episode, Bryan answers Howard's question about how to deploy a dehumidifier (dehum) in a sealed home. He addresses things like location and fresh air requirements in green-grass markets with high dew points.

Before deploying a dehumidifier, you will need to know about the climate, the structure, and the client's complaints, budget, and comfort goals. You need to make sure the HVAC system is properly installed; the most common obstacle to proper dehumidification is oversizing. HVAC systems need a cold coil to pull moisture out of the air, and we need adequate (but not too much) ventilation in the structure before deploying a dehumidifier. Common obstacles include leaky structures, venting exhaust air into the attic, and constantly running exhaust ventilation (like range hoods or bath fans).

Bryan's preferred setup is to have a dedicated dehumidifier just for the sealed attic, though you can make the HVAC do this if you plan it out during the construction phase. If you bring in outdoor air, you should plan to bring it in through the dehumidifier, but that can interfere with attic dehumidification. You can either use two dehumidifiers or use powered dampers to dehumidify either the attic or house at different times.

You can consult the expertise of groups like the HVAC Grapevine and manufacturers like Santa Fe Dehumidifiers. HVAC School also has a range of dehumidifier topics; you can search for videos, podcasts, and tech tips on the topic in the app.

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 episode of the Spidey Sense series, Bryan and Bert dive deep into the art of refrigerant leak detection, sharing their wealth of experience and practical tips for HVAC technicians. They emphasize the importance of using one's senses and observation skills before relying solely on electronic tools, highlighting how this "Spidey Sense" approach is a hallmark of senior-level expertise in the field.

Visual and tactile cues, including warm suction lines, frosted components, and signs of oil, are vital. Different symptoms point to specific kinds of leaks and various scenarios, so you need to understand the behavior of the system.

Bryan and Bert also discuss the strategic application of soap bubbles, electronic leak detectors, and nitrogen for pressurization. Each method has limitations, and you'll need to know when to employ them for maximum effectiveness. When detecting leaks, consider recent home renovations or equipment vibrations that might contribute to leaks.

Topics covered in the podcast include:

• Visual and tactile cues for identifying potential refrigerant leaks
• The debate on frosted lines as indicators of low refrigerant charge
• Proper use of electronic leak detectors and their limitations
• Strategic application of soap bubbles in leak detection
• The importance of checking common leak locations (e.g., flare fittings, evaporator coils)
• Considerations for leak detection in newly installed or recently serviced systems
• The role of nitrogen in leak detection for systems with very low refrigerant charge
• Estimating the severity of a leak based on system pressure and charge level
• The pros and cons of isolation tests for line set leaks
• Techniques for detecting very small, slow leaks that might not show up in pressure tests
• The potential use of ultrasonic leak detection tools
• The importance of thorough inspection and patience in the leak detection process

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 short Q&A podcast episode, Bryan answers Edward's question about how to deal with customers who ask, "Why didn't you notice it last time?"

There isn't an easy answer to that question. The truth is that air conditioning and home health and comfort issues are complicated, and it's entirely possible that an issue simply went unnoticed (or the symptoms simply weren't apparent yet). The HVAC industry doesn't have a standard slate of tests that can give a comprehensive view of everything that's wrong with a system all at once. It's similar to how a doctor can offer a second opinion that differs from the first doctor you saw.

You have to determine whether the customer wants to place blame or solve the problem when they ask, "Why didn't you notice it last time?" Sometimes, we need to dig deeper to find the root of the problem. We can offer advanced diagnostics and be honest about what that will entail (including pricing), though it's natural for customers to be apprehensive about being sold options. However, we don't want to avoid pursuing solutions either.

There are ways to talk about previous sloppy or incomplete work without placing blame on another technician. The immediate problem is what requires attention, not the last person who worked on the system. Ask the customer to state their goals and the results they want to see, and you can forge a path ahead.

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.

In this short Q&A podcast episode, Bryan answers a question about drain traps and static pressure. This question was sent by Stephen with The Comfort Squad when he noticed an uptick in nuisance calls on retrofit systems that kept having their secondary drain pans filled.

In negatively pressurized systems (i.e., straight-cool or heat pump units, not gas furnaces), air can pull water back into the drain line. The evaporator coil is under negative pressure because the blower is on top of the evaporator coil.

The rule of thumb for trap depth is that it should be greater than or equal to twice the return static pressure (which is why a 1" deep trap is typical for systems with 0.5" return static pressure). However, return static can have some variation, and it's also not a great idea to use the TESP for this measurement because the return static could be greater than the supply. It makes most sense to account for the highest possible return static you will see.

1" is only sufficient if 0.5" return static pressure is the most you will see, so bigger is usually better in all cases. If you can install a 2" or 3" trap, you'll typically have your bases covered without having an excessive trap.

We also wrote a tech tip about this topic: https://hvacrschool.com/drain-trap-depth-and-negative-pressure/

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.

In this short Q&A podcast episode, Bryan answers Kenton's question about how to stop vents from condensating, especially when sealing and insulation don't do the trick.

When approaching a condensation problem, we have to consider the source of moisture and where the condensation is happening. Moisture that builds up on top of the vent comes from attics with a high dew point. (It's not because hot meets cold! Relative humidity and dew point are a lot more important, though hot air is able to hold more moisture.) Warm, moist air with a high dew point hits a colder surface when there is improper sealing and insulation where the duct attaches to the boot.

People often attempt to solve condensation issues by adding insulation, which actually has the opposite effect because it reduces the surface temperature; condensation worsens. Some people also increase attic ventilation, but that may cause pressure imbalances that drive moist air into the conditioned space.

The best way to control attic conditions is to seal and then dehumidify the attic, though it is an expensive and time-consuming measure. Exhaust vents that end in the attic also add moisture to the attic. Sealing vents and other areas where attic air can seep into the space is another best practice, as is deploying a humidity control strategy. Reducing humidity can happen with a dehumidifier and proper sizing so that the HVAC equipment has long runtimes with a cold evaporator coil (achieved with lower system airflow).

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.

Subscribe to our YouTube channel.

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