HVAC School - For Techs, By Techs

In this short podcast, Bryan and Roman discuss premature coil failure in ductless mini-splits and VRF equipment. 
These coils are susceptible to a few different types of corrosion. Warmer coil saturation temperatures and shorter runtimes result in lower latent capacity; whatever moisture is on the coil dries on the coil instead of draining out. Minerals and chemicals (including chlorides from bleach or cleaners) interact with the coil and may cause corrosion, including formicary ("ant's nest") corrosion. Leaks and corrosion may be environmental rather than entirely attributable to manufacturer defects.
Technicians can use proper cleaners with correct dilution ratios and rinse the coils. In situations where the environment contributes to coil corrosion, such as with substances off-gassing or dealing with coastal air, we will need to dilute the pollutants by ensuring proper ventilation. Dilution needs to be intentional, especially in hot-humid climates, and ventilating dehumidifiers with good filtration may be a good move. Source control and filtration are also good mitigation strategies, and clear, open client communication can help clients understand the problem and make informed decisions about their HVAC system.
This episode contains embedded sponsor messages from Refrigeration Technologies, Carrier, NAVAC, and Fieldpiece.
Resources
Coil Corrosion w/ Kevin Hart and Bryan Orr
Living in a World of Acids (and why HVAC coils are secretly crying for help)
HVAC School calculators
Submit a podcast question
Learn about the GRIT Foundation
Purchase your tickets or learn more about the 8th Annual HVACR Training Symposium at https://hvacrschool.com/symposium.

In this live episode, Bryan sits down with Jim Bergmann of measureQuick and NAVAC trainers Zane and Jesse Stewart for a deep, technician-focused conversation about advanced refrigerant recovery. The group covers diverse system types and environments, including low-ambient recovery.
Recovery machines cannot pump straight liquid, which we need to be mindful of during service. That said, vapor-only recovery works fine for small charges, but push-pull recovery becomes worthwhile once a system holds more than roughly ten pounds of refrigerant. Refrigerant and tank contamination, as well as general safety (including tank fill limitations), are a couple of other field challenges worth considering in our recovery best practices. 
Some best practices to take away from this episode include attaching to the vapor side of the tank (and inverting it), pulling Schrader cores, using large hoses instead of manifold gauges, and keeping the recovery tank cool to eliminate restrictions. 
This episode contains embedded sponsor messages from Refrigeration Technologies, Carrier, Copeland, Santa Fe Dehumidifiers, and TruTech Tools.
Resources:
Don't Overfill Recovery Tank Cylinders the Easy Way
Recovery Tank Safety
Recovery Tank Capacity
Push-Pull Recovery
Recovery Best Practices w/ NAVAC
HVAC School calculators
Submit a podcast question
Learn about the GRIT Foundation
Purchase your tickets or learn more about the 8th Annual HVACR Training Symposium at https://hvacrschool.com/symposium.

In this short podcast episode, Bryan and Roman talk about the A2L & refrigerant transition again, particularly sensors on R-454B and R-32 equipment. 
Since the beginning of the A2L transition, we have seen the equipment evolve and begin requiring accessories, including refrigerant sensors and blower recirculation systems (BRS) or dissipation boards. In a BRS, the blower turns on and dilutes the refrigerant in the space to keep the refrigerant concentration below the lower flammability limit (LFL) and prevent ignition. Some systems may also have isolation valves and pump themselves down whenever the A2L sensor trips. These sensors use MOS technology, which measures gas changes by tracking electrical connectivity shifts; they have limited lifespans and can become corrupted over time. 
In the field, you may notice a running fan without the outdoor unit running. Some diagnostic boards might give you error codes, but if you don't and don't have 24V when you troubleshoot the issue, you may want to check the sensor. The sensors could be wet, tripped by VOCs, or even have been cut out. 
This episode contains embedded sponsor messages from Refrigeration Technologies, Carrier, TruTech Tools, Fieldpiece, and Filtrete.
Resources
A2L Dissipation Boards and Leak Sensors
HVAC School calculators
Submit a podcast question
Learn about the GRIT Foundation
Purchase your tickets or learn more about the 8th Annual HVACR Training Symposium at https://hvacrschool.com/symposium.

In this episode, Bryan sits down with Mike Pastorello, owner of Refrigeration Technologies, and Ashley Lynds, director of education and brand management for Viper, to talk about the company's roots, its newest product launches, and where the brand is headed next. This podcast focuses on "The Lab" and how it integrates field technicians with product development.
Refrigeration Technologies was built on a "for techs by techs" philosophy after John, an HVAC technician with a chemistry background, began inventing products to solve his own field problems. Now, technicians are using their field problems to inspire innovation in the Refrigeration Technologies lab, and the Easy Dose is the first product that was developed, tested, and distributed via the "Lab" initiative. 
The team also discusses chemical safety in their approach to products and what's really inside products like the Viper Pan & Drain Treatment and Nylog.
This episode contains embedded sponsor messages from Refrigeration Technologies, Carrier, NAVAC, Fieldpiece, and AHR Expo 2027.
Resources:
Refrigeration Technologies
AHR Expo
Careful With Cleaners
HeatShield Demo
HVAC School calculators
Submit a podcast question
Learn about the GRIT Foundation
Purchase your tickets or learn more about the 8th Annual HVACR Training Symposium at https://hvacrschool.com/symposium.

In this short podcast episode, Bryan and Roman talk about the ethics of IAQ, particularly in terms of microbial growth testing vs. remediation conflicts, based on Roman's recent experience hiring a mold assessor and then a remediation expert in his home. Remediation is governed by S520 of the IICRC.
Microbial growth is tricky because it is often hidden and has real health effects, but there is a history of fraud in its assessment and remediation. To help combat that fraud, in Florida, assessment and remediation are two separate practices with two separate licenses. Roman got to see the differences in action by working with different assessment and remediation professionals and witnessing how the two practices depend on each other but differ.
First, an assessor came to Roman's house with testing equipment and a means of collecting lab samples; this assessment started outdoors and continued indoors, and the assessor produced a thorough 87-page report with the tool findings, lab findings, and pictures. As with HVAC, the results are based on science and data, and reputable assessors are licensed, independent, and have the tools and training to carry out the job without using scare tactics on homeowners.
After the assessment, remediation must be done separately. In Roman's home, all equipment was isolated, and the house was brought under negative pressure with HEPA filtration. There was also surface cleaning and HEPA vacuuming. Then, after remediation, there is a post-remediation verification (PRV). The PRV is carried out by a mold assessor, not a remediator, and determines whether the remediator did their job (and in some states, like Florida, there are criminal penalties for referral payments between assessors and remediators). A PRV consists of IAQ tests and lab measurements, and the results should reveal lower numbers than the original assessment and the outdoor air.
 
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Purchase your tickets or learn more about the 8th Annual HVACR Training Symposium at https://hvacrschool.com/symposium.
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