UV Lights

By March 6, 2017

A quick note about UV lights: they work like sunlight in that they prevent and kill many types of bacteria and fungi when exposed to the light on surfaces. They do not generally do a great job of killing spores suspended in the air stream.

UV lights are great at killing yucky stuff on surfaces like coils, blower wheel, and panels. They won't “kill” everything in the airstream, and they don't capture anything.

Also, be careful about what the UV is allowed to shine on. It will deteriorate most wire insulation and can deteriorate and discolor many other plastics.

Finally, don't look at a UV light for any amount of time. I once spent a very uncomfortable day in bed after damaging my eyes from looking at UV indirectly for only a few minutes.

UV can be great, but it's not a fix-all. Always be careful as to where the light is going.

—Bryan

Check out our most recent video

How to Evacuate an AC system, Full Vacuum Procedure

Our latest Podcast

HVAC School – For Techs, By Techs

Real training for HVAC ( Heating, Ventilation, Air Conditioning and Refrigeration) Technicians. Including recorded tech training, interviews, diagnostics and general conversations about the trade.

Phil Barr and Nathan Orr join the podcast to talk about wiring refrigerated cases in commercial spaces, including convenience stores and supermarkets.

Cases may be medium-temp (or high-temp, in some cases) or low-temp. Medium-temp cases can typically defrost on their own during the off cycle, and low-temp cases may have electric or hot-gas defrost to help get ice off the coil at set intervals. Each system has an evaporator (and fans), compressor, condenser, and metering device (often a TXV or EEV), and low-temp refrigeration may have anti-sweat heaters, EPRs, and other components to manage.

Challenges arise when electricians don’t understand the fundamentals of commercial refrigeration, especially as the electrical circuitry relates to the refrigeration circuit components. Time crunches also apply a lot of pressure to electricians and refrigeration technicians. Testing circuits, such as fans and lighting, or using circuit tracers are good ways to get an idea of how an existing system is wired. Labeling wires and breakers and keeping those labels or information in places where others can read them can help you and other electricians in the future.

One of the most common issues happens when technicians or electricians refuse to test out their results to catch their mistakes before callbacks happen. Even seemingly small electrical issues, such as improper lighting, can cause costly losses if product spoils and cannot be sold.

Phil, Nathan, and Bryan also cover:

Changes in central and case control strategies over time
Challenges with retrofits and remodels
Central lighting controls
Mistakes that can be made when labeling wires or breakers
Working against the clock
Terminal blocks, DIN rails, and connectors
Making mistakes and the origin of animosity

Learn more about the HVACR Training Symposium or buy a virtual ticket today at https://hvacrschool.com/symposium.

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.

Search Episodes

Wiring Refrigerated Cases w/ Nathan & Phil

09/14/2023

Bryan Orr

Things to Keep out of the System – Class

09/07/2023

Bryan Orr

ACH (Air Changes Per Hour) – Short #174

09/05/2023

Bryan Orr

Oil Return and Refrigerant Charge in VRV w/ Roman Baugh

08/31/2023

Bryan Orr

Magical Air Cleaning Oxides? – Short #173

08/29/2023

Bryan Orr

Can Filters Capture Viruses? – Short #172

08/22/2023

Bryan Orr

Heat Pumps + Inverters w/ Joey H

08/17/2023

Bryan Orr

Get Air Where it Needs to Go W/ Joey H.

08/10/2023

Bryan Orr

Business Round Table – Tersh, Peterson, Holt

08/03/2023

Bryan Orr

Cap Tubes and Flow Facts – Short #171

08/01/2023

Bryan Orr

Search Results placeholder

Comments

Gabe willard

11/4/16 at 11:38 PM

Thanks for that bit. I have some coils that have mold on them this might help.

Bill Brown

12/19/17 at 10:04 AM

This is all correct. To add a couple of things. If the UV lights are mounted in such a way that the light hits carpet, it will bleach it.

As for what it does or doesn’t kill, that is important. Also important is what do you do after the lights “kill” the “bugs” – are they safer dead or alive? Depends on what it is. You should follow this up with good filtration to capture what you killed. That of course opens a whole other conversation on filtration and the effect if has on static duct pressure.

Related Tech Tips

TXV Bulb Placement

When mounting a TXV bulb or checking bulb placement, there are a few important considerations (listed in order of importance): Mount the bulb on the suction line. Flapping in the breeze is no good. Mount it TIGHTLY with a proper metallic strap (usually copper, brass, or stainless steel)—not with zip ties or tape. Position it on […]

Cooling Capacity Isn't Always What it Seems

We all learned how to read the tonnage off of a model number within a few weeks of beginning in the trade. What you may (or may not) have learned is that just because something has an 036 in the model number, that does NOT mean it actually produces 36,000 BTU/hr. It doesn't reach the […]

Blowers, Props, and How They Behave (or Misbehave)

Fan laws and fan curves are a deep subject with a lot of nuance and variation. Just to get our heads around the subject, let's focus on two different types of fans that we see all the time in HVAC: the prop/axial type and the radial/centrifugal type. Centrifugal/Radial As we increase the pressure differential across […]

More tech tips