#expansion valve

Tech Tips:

The piston (fixed orifice) and TXV (thermostatic expansion valve) are the two most common metering devices in use today, though some modern systems utilize an electronically-controlled metering device called an EEV (electronic expansion valve). It should be noted that there are other types of fixed-orifice metering devices, like capillary tubes; however, their use is not […]

What to Check Before Condemning the TXV

I just noticed this portion of the Carrier air handler sticker for the first time the other day. I'm like most techs; it's easy for us to ignore the great info posted right in front of us on the data tag. That's because so many of the notices contain info we are used to seeing. […]

How to Diagnose a TXV Failure

There has been much written and many jokes made about the misdiagnosis of TXV (thermostatic expansion valves), and rightly so. This article will cut straight to the point to help those of you who may still need a bit of clarification, and hopefully, we will save the lives of a few TXVs and the pocketbooks […]

Rack Refrigeration Cycle Part 9 – Mechanical Expansion Valves

Expansion Valves – What Does and Doesn’t Matter?

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In this enlightening episode, we sit down with Mike, a 20-year veteran from DITEK, a leading American manufacturer of surge protection devices based in Largo, Florida. The conversation begins with a brief discussion about recent hurricane impacts in the Tampa Bay area, where DITEK maintains its 65,000-square-foot manufacturing facility. Mike shares how the company, despite facing challenging weather conditions, continued its operations and maintained its commitment to American manufacturing.

The bulk of the discussion centers around surge protection technology and its critical importance in protecting HVAC systems and other electronic equipment. Mike provides an excellent analogy, comparing surge protectors to pressure relief valves for electrical systems. He explains how Metal Oxide Varistors (MOVs) work as semiconductors that create low impedance paths to ground when voltage exceeds certain thresholds. The conversation delves into the evolution of MOV technology, particularly the development of thermally protected MOVs that provide enhanced safety features.

The episode also addresses common misconceptions about surge protection, particularly the belief that surge protectors are primarily for lightning protection. Mike explains that while lightning strikes are a concern, especially in areas like Florida, approximately 65% of surges actually originate from within facilities themselves, often from equipment cycling on and off or other power quality issues. He emphasizes the importance of proper installation, particularly regarding ground connections and lead lengths, noting that every six inches of wire length can add about 100 volts to the clamping voltage of the device.

Key Topics Covered:

DITEK’s history and commitment to American manufacturing
Basic principles of surge protection and how MOVs work
Evolution of MOV technology and thermal protection features
Difference between transient voltage and temporary overvoltage (TOV)
Importance of proper grounding and lead length in surge protection
Cascading surge protection strategy for comprehensive protection
UL testing standards and voltage protection ratings (VPR)
Common misconceptions about surge protection
Impact of aging electrical infrastructure on power quality
Importance of customer support and ethical business practices
Installation best practices for surge protection devices
Relationship between ground resistance and surge protector performance
Types of surge protective devices (SPD) and their classifications

Learn more about DITEK at https://www.diteksurgeprotection.com/.

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