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Latest Episodes:

Indoor Air Quality Map & Compass w/ TZOA May 06, 2021

Show notes

In this podcast episode, Ben Reed from TZOA, a disruptive air technology brand, joins us to discuss the indoor air quality map and compass.

We spend a majority of our lives indoors, so TZOA tries to improve IAQ in homes to keep us healthier. HVAC manages airborne chemicals, so indoor air quality ties right into our industry; HVAC technicians will become more valuable when they become well-versed in IAQ technologies.

In residential HVAC, we are already used to listening to customer complaints and observing the home. Technicians (and even IAQ products) can "map" out the customer concerns and home features to develop a comfort and home-health solution. TZOA is working on putting together that "map and compass" model to optimize home health and comfort by noting problem areas and pointing us to the tools to solve the problem.

HAVEN uses a central air monitor (CAM), which is an in-duct, whole-home IAQ monitor that measures particulates, temperature, and humidity. The monitor pairs with software to fulfill the "map and compass" model and assist with diagnosis. The air monitor and software help dispel uncertainty around IAQ products while providing accurate readings that point to solutions.

It's also worth noting that HAVEN's tools can only be purchased and installed by HVAC professionals. So, they're helping bridge the communication gap between technicians and customers. TZOA is also attempting to build trust and confidence in IAQ products through education, collaboration with industry experts, and allowing HVAC technicians to use and experiment with their products.

Ben and Bryan also discuss:

HAVEN and TZOA's beginnings
IAQ uncertainty and reputation
Multiple chemical sensitivity
Ventilation and dilution
The future of TZOA products
TZOA's personal use program
Working with reputable companies and people
Integrating IAQ into maintenance plans

Learn more about TZOA and HAVEN at haveniaq.com.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Copeland 2-stage ZPS Scroll Compressors Apr 29, 2021

Show notes

In this podcast episode, Bryan and Trevor Matthews of Emerson Canada discuss the Copeland 2-stage ZPS scroll compressors. Please join us by following along in bulletins AE4-1428 and AE4-1365.

The ZP91KCE to ZP143KC Copeland compressors don't have internal pressure reliefs (IPRs). Those higher-pressure compressors make very loud noises when they go off, and it'll blow hot discharge gas on the internal overload to shut down the compressor. Some scroll compressors have temperature operating disks (TODs), which are bimetal disks that open upon a temperature increase and reroute the gas. Other compressors have advanced scroll temperature protection (ASTP), which is a snap-back disk near the floating seal.

You don't just want to shut the suction service valve to pump the scroll down. Instead, common service procedures include checking voltage to the compressor, the internal motor, the blower/fan operation, the suction pressure, and the compressor wiring.

If you install crankcase heaters for oil management, be sure to install them correctly to avoid overheating the compressor. You'll also want to verify that crankcase heater voltage and ensure that it is properly grounded.

Two-stage modulating Copeland scrolls work with a 24v DC solenoid in the scroll set. That solenoid energizes and de-energizes, which either fully or partially loads the compressor. Load matching is ideal for efficiency and comfort, meaning that the two-stage Copeland scrolls perform well in those areas. Unsurprisingly, the fully-loaded option draws more current than the partially-loaded option. These two-stage compressors don't have IPRs, so you will need a high-pressure control set to 650 PSI.

Trevor and Bryan also discuss:

TOD vs. ASTP
Operating envelopes
Hipot testing
Single-phase compressors
Using Copeland compressors in pool heaters
Oil and refrigerant dilution
Wiring up CoreSense
Reversing valve sizing issues

Visit climate.emerson.com for more resources.

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.

Screw Compressor Talk w/ Vilter Apr 22, 2021

Show notes

In this podcast episode, Bryan, Trevor Matthews, and Jim Dick of Emerson talk about the screw compressor and how it works. This time, they focus on the Vilter single-screw compressors.

Vilter is an industrial compressor division of Emerson (compare to Copeland). Vilter also makes reciprocating compressors, but the screw compressor is its claim to fame; you may want to consider using a screw compressor when you want greater capacity and control than a reciprocating compressor. Screw compressors also work well for applications with constant loads; they do, however, have microprocessors that can monitor system performance to maximize efficiency.

Vilter uses a compressor with a single screw, whereas most compressors have twin screws. Twin screws have a motor that continuously turns the rotor, which causes the screws to mesh together; the compression happens as gas fits between the screws, and the gas volume decreases as the space between the screws closes. In a single-screw compressor, the gas compresses on the outside of the screw. In any case, we must seal the gas in the flutes, and oil helps us with that. Liquid should not get into either type of screw compressor, as liquid is not compressible and will damage the compressor.

When you service a screw, the oil temperature and discharge pressure will likely be the most important values to watch out for. During maintenance inspections, you'll also want to pay special attention to the bearings, the four pressure transducers, and oil filtration system.

Jim, Trevor, and Bryan also discuss:

Microprocessors
Star rotors
Oil uses, management, and components
Motor RPM
Multiple compressors and added capacity
Calibrating pressure transducers
Zeroing vs. calibrating
Suction screens
Jim's interesting findings
Injecting oil
Value engineering and consistency

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.

Check out our handy calculators HERE.

Condensation Problem Solving - Short 116 Apr 20, 2021

Show notes

In this short podcast episode, Bryan talks about condensation and how HVAC technicians can solve condensation-related problems. He also discusses humidity control and how that can affect sweating.

We may have heard the phrase, "Condensation is where hot meets cold." That's not necessarily true; while it may seem that sweating happens where hot meets cold, the dew point is the main cause. We won't see condensation unless we have air that reaches the dew point. When air flows across surfaces that have a temperature below the dew point, you'll start to see sweating on the surface.

Clouds and fog indicate liquid water in the air; if you see fog, then you will know that the ambient temperature is below the dew point. We also can't see steam; steam is water vapor, but the "steam" we see is actually liquid water. Water vapor is also lighter than air, so it rises in the vapor form.

When we see condensation or sweating, we must ask ourselves if the surface is colder than it's supposed to be. Ducts can sweat when the airflow is too low, and the air handler can sweat when the evaporator freezes. If we were to heat the air as a solution, we can decrease the relative humidity, but heating the air doesn't change the dew point or total moisture content.

The next step is to make sure we don't have infiltration at boots or can lights. Infiltration can cause sweating, especially in unconditioned spaces. You'll also want to make sure that the duct insulation is straight and that the ducts have been properly strapped. The house itself can also cause infiltration, especially through fireplaces and chases; a blower door test can help you determine the leakiness of the home. Ventilating dehumidification may also work as a solution.

Check out Richard Sims's presentation on our YouTube channel HERE.

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.

ECM Types and Applications Apr 15, 2021

Show notes

In this podcast episode, Bryan and Chris Mohalley of Regal Beloit discuss the different types of ECM. They also cover applications where you can expect to find ECMs.

In the HVAC industry, we typically use three types of motors: constant-torque, constant-airflow, and constant-speed. Every ECM works on electronic commutation, so constant-torque motors use that to maintain torque output (X13). The constant-airflow motor is also known as the variable-speed motor, and it is one of the first ECM types. We typically only use constant-speed motors in outdoor fan motor applications. Likewise, we generally use the first two motor types for indoor fan motors inside air handlers.

ECMs were NOT designed to address the static pressure problems of PSC motors and duct issues; variable-speed motors may attempt to compensate for duct problems, but that's not its purpose. (Variable-speed motors work like cruise control in a car.) However, when motors compensate for poor duct systems, they could run higher RPM than desirable in order to hit the system targets and can generate excess heat.

Constant-torque motors maintain a certain torque value, which can get tricky when the loads begin to vary. When static pressure goes up, there's less air in the system, which means that there's less air for the wheel to move (a smaller load). Current and RPM can increase when static pressure goes up, but the torque would stay the same.

Chris and Bryan also discuss:

What is a variable-speed motor?
Permanent split capacitor (PSC) motors
Duct sizing and design
Static pressure and motor life expectancy
Reactive power and power factor
Torque vs. speed taps
Blower performance curves
Different series of motors
PWM (pulse-width modulation) and inputs
Setting DIP switches
Evergreen VS
Why should you read the manual?

Check out some more ECM resources at regalmmu.com.

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.

The Right and Wrong Way to HVACR w/ Eric Kaiser Apr 08, 2021

Show notes

In this podcast episode, Bryan and Eric Kaiser discuss the right and wrong way to do HVAC/R jobs and approach HVAC/R work.

Breaking things down into "right" and "wrong" categories is a rather simple way to approach a problem; we throw nuance and alternatives out the window, which can be worse than doing something "wrong." Instead of viewing things as right and wrong, we would be better off if we looked at our objectives and focused on solving problems instead of being right.

Although there are surely correct ways to pull a vacuum, it's more useful to set standards than argue about what's right. Set standards that are appropriate for the situation (the equipment, your tools, your skill level, etc.). Of course, it would also be best if we could try to set our egos aside. We need to have humility and acknowledge that we're all trying to improve for the sake of our customers. That said, we could all benefit from focusing on achieving successful outcomes instead of being "right."

Ultimately, many of our struggles to determine right from wrong can be solved by listening to the customer. Our goal is to tailor our practices to our customers' needs, even in commercial work where customer service isn't as important. Being overly dogmatic doesn't do much to help a customer, and it fails to account for the unique details of each situation we encounter in the field.

Eric and Bryan also discuss:

The right vs. wrong way binary
Maturity
Situational awareness
Evacuation best practices
Customer discretion and expectations
Do aesthetics matter?
Commercial vs. residential HVAC
Evaluating suppliers and manufacturers reasonably
How oil and parts have evolved
Flowing nitrogen
Setting goals

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.

How EC Motors Work Apr 01, 2021

Show notes

In this podcast episode, Bryan and Chris Mohalley from Regal Beloit discuss EC motors. They also describe ECM applications and how those motors work.

EC motors (ECMs or "ECM motors") are electronically commutated motors. These motors are generally three-phase AC motors operated by a drive; that drive is a combination of an AC-to-DC converter, microprocessor, and frequency drive. So, the frequency delivered to the motor is generated electronically.

When it comes to inputs, the ECM works like a printer. One input provides power (from the wall to the printer). The other cable tells the printer what to do and when to do it (from the computer to the printer). An ECM will have a line voltage connection and a constant 24v communication input. Constant-torque ECMs work like PSC motors in the way they use control taps; other ECMs may use DIP switches.

ECMs are direct-drive motors that differ from PSCs because they don't have a capacitor. EC motors also have a permanent magnet, which can affect diagnosis if you rarely come across indexing.

AC motors use magnetism; when you pass energy through the stator coil, the coil creates an invisible magnetic field, which then induces a magnetic field into the rotor. When the rotor picks up a magnetic effect, it starts to spin. EC motors have that magnetic effect in their magnets.

Chris and Bryan also discuss:

Regal Beloit's history and brands
Effectiveness of metaphors and acronyms in our industry
Constant-torque ECM vs. variable-speed motor
Motor modules
Changes to the ECM design over time
ECM manufacturers
Three-phase power and controls
Reading ohms
Glued-on vs. slotted magnets
RPM and the effects of poles and frequency of power delivered

For more resources for EC motors, check out regalmmu.com.

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.

Stacking Liquid vs. Mechanical Subcooling - Short 115 Mar 30, 2021

Show notes

In this short podcast episode, Bryan compares strategies for increasing the subcooling, including stacking liquid and mechanical subcooling.

Subcooling is a consequence of condensing; when we change the refrigerant from a vapor to a liquid, it will drop below saturation temperature after it becomes completely liquid. There are three phases in the condenser: desuperheating, condensing, and subcooling. The first few rows of the coil reduce the superheat of the vapor entering the condenser. Once there is no more superheat, heat rejection helps the saturated refrigerant transform into a liquid entirely. Near the end of the coil, liquid refrigerant can keep losing heat, and it becomes subcooled.

We can only achieve subcooling by stacking liquid in the condenser. When you stack liquid in the condenser, it can give off its heat to the outdoor air. However, too much subcooling isn't necessarily a good thing. Your condensing temperature should be above the outdoor temperature; we call this value the condensing temperature over ambient (CTOA). When your condensing temperature is too close to the ambient temperature, you won't get much heat rejection.

If your subcooling goes up because you're stacking too much liquid, you'll drive up your CTOA and head pressure. If you increase your head pressure, you'll increase your compression ratio. Your efficiency will suffer. So, when stacking liquid, you'll want to find a happy medium. However, in systems with liquid receivers, you may not see much liquid stacking at all.

Getting some extra subcooling can boost your system capacity. We have some mechanical subcooling devices that use heat exchangers to drop the temperature of the refrigerant in the liquid line. That way, the refrigerant can absorb more heat when it's in the evaporator coil.

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.

Proper Design For Ductless and Ducted HVAC Systems Mar 25, 2021

Show notes

In this podcast episode, Bryan, Chad, John, and Allison discuss proper design for ductless and ducted HVAC systems, especially mini-splits. They also discuss potential future improvements to equipment and duct designs.

Mini-splits are smaller than traditional HVAC units, so they make zoning a bit easier. However, load calculation plays a huge role in equipment selection and zoning because you must get the right number of zones to match the equipment capacity and meet your load requirements.

Proper design is difficult, and a common mistake includes using one piece of equipment to serve the whole house, especially on new constructions. Some designers also don't offer multiple options to the customer, which can be a mistake. Most of the time, we end up downsizing systems, not making them larger. Failing to smooth out turns in the ducts and use proper fittings can also negatively affect airflow and pressure. If you're working on new construction, you'd be best to get an idea of the building design ahead of time and clearly communicate what you need to create a proper duct design.

Going from traditional to mini-split duct design has a bit of a learning curve. It's easy to make mistakes when you aren't prepared to deal with the function of variable capacity in mini-splits. You can avoid making mistakes by learning about the equipment (and duct materials) during the selection process, not after the selection.

Chad, John, Allison, and Bryan also cover:

Adjusting the structure
Replacing old equipment with higher-SEER equipment
Selecting filters and filter grilles
Static pressure options
Total length vs. total equivalent length
Register sizing
Flex ductwork
Drop ceilings
Texas's energy grid and how it relates to potential setbacks
Replacing furnaces with heat pump systems
Future micro-split heat pumps

Check out energyvanguard.com and think-little.com.

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.

Atmospheric Pressure - Short 114 Mar 23, 2021

Show notes

In this short podcast episode, Bryan explains what atmospheric pressure really is, pressure units and conversions, and why those are matter.

Atmospheric pressure is the weight of the air around us pushing down on us. We normally see that value expressed as 14.7 PSI (or 0 PSIG). Before we dive too deep into atmospheric pressure, we should understand some basic pressure units.

We may see pressure expressed in microns when we're pulling a vacuum; we are trying to pull the atmosphere out of the system, so our goal is to get as close to 0 as possible. Whenever we pull a vacuum, we get liquid water to boil off and remove molecules inside the system. The industry standard is 500 microns. 14.7 PSI(A) is equivalent to about 760,000 microns, so the micron is an extremely small pressure measurement. You may also see the bar scale, which is equivalent to 1 atmosphere (atm). One bar equals just over 14.5 PSIA.

You may also encounter the Pascal unit, which is common on the building science side of our industry. One PSI is equal to 6,894.76 Pascals. When we look at small pressures, such as static pressure or gas pressure, we may use the inch of water column ("wc). One inch of water column is equal to 248.84 Pascals. We also have inches of mercury ("Hg) and the torr (mmHg), which are related to the micron. All units are interrelated, but they have their appropriate applications.

Atmospheric pressure matters when altitude enters the equation. When the pressure changes at a higher altitude, the air density also changes. The air is less dense, so you have less oxygen in the air. When you have less oxygen in the air, combustion is more likely to be incomplete. So, we may need to derate furnaces. We also need to take altitude into account when we calibrate gauges at significant altitudes compared to sea level.

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.

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