Author: Bryan Orr

Bryan Orr is a lifelong learner, proud technician and advocate for the HVAC/R Trade


In this episode of HVAC School Bryan talks with Tim Bagnall about flowing nitrogen. We discuss:

  • The Proper tools and flow settings for brazing
  • How the pressures should be set to SCFM and not PSI
  • The possibility that geography may contribute to scale
  • How to flow nitrogen in a practical way
  • And More…

As always if you have an iPhone subscribe HEREand if you have an Android phone subscribe HERE



In this episode of HVAC School Bryan talks with Jeremy Smith and they discuss

  • Reznor startup
  • Being on call in the refrigeration world
  • differences and similarities between rack refrigeration and A/C
  • Hot gas and electric defrost
  • Glycol refrigeration systems
  • Subcool and Superheat
  • Refrigeration TXV settings
  • EPR valves and their settings
  • Rack manifold pressure

And Much more…

As always if you have an iPhone subscribe HERE and if you have an Android phone subscribe HERE


In this episode Bryan talks to Justin Skinner about gas furnace sequence of operation.

we talk about:

  • Low Voltage Wiring
  • Boilers
  • Forced and Natural Draft
  • Flame rectification
  • Cleaning Flame Sensors
  • Gas Pool Heat
  • Silicon Nitride and Silicon Carbide
  • Hot Surface and Intermittent Pilot

As always if you have an iPhone subscribe HERE and if you have an Android phone subscribe HERE



Let’s face it. It doesn’t get super cold in Central Florida regularly but when it does EVERYONE FREAKS.

In this episode we talk about:

  • Burning off heat strips
  • Heat Pump Defrost Mode
  • Gas Pool Heater
  • Heat Pump Pool Heaters
  • The thermodynamic principles of heat pump heating
  • Defining BTUs
  • LP vs. NG

And much more…

This podcast is in an unedited “meeting format” and is not usually the type of thing you will get on HVAC school, but I still think it may benefit junior techs and office staff.

As always if you have an iPhone subscribe HERE and if you have an Android phone subscribe HERE



We all see a lot of questions about, dyes, leak stoppers, lubricants, inhibitors and snake oil.. all designed to go in the refrigerant circuit and “improve” something.

I just go back to what Ray Johnson always said (Ray is one of my early heroes in the biz and taught me a lot at Carrier classes)

“Oil and refrigerant”

If it isn’t oil and refrigerant, it doesn’t belong in the system.

Now I know there are rare exceptions… Heck, Carrier has a tech bulletin from 2014 dictating that Zerol Ice should be added to certain systems due to TXV sticking issues.

But when in doubt.. Just oil and refrigerant.

— Bryan


First question is.. Does it really matter if the the speed taps on a motor are run or common? Well yes.. sorta.

It helps in certain cases so you can identify if it is an open winding or an open thermal overload. The thermal overload breaks common but you will still read a path between Run and Start with an Ohmmeter.

Also, I had always stated that the same leg of power that feeds run also feeds start. This is just a simplistic way of saying that the leg of power opposite the start winding on the run capacitor should be fed from the same leg of power as run and the opposite leg as common.

The other thing I always said is that common isn’t really a “winding”, but rather it’s a point in a winding.

What I learned is that in the case of a multi tap blower, the speed taps actually are “commons” because they are connected to the opposite side as start and they ALL break when the motor overheats.

Here is a video link to where Nathan and I prove it – and yes… Nathan was right


1. What is a BTU a measure of?

Question 1 of 10

At what temperature does water boil?

Question 2 of 10

The heat the earth receives from the Sun is an example of

Question 3 of 10

In a sealed container if a gas is cooled it….

Question 4 of 10

As temperature increases molecular velocity

Question 5 of 10

A refrigeration circuit…

Question 6 of 10

Latent Heat is…

Question 7 of 10

Blowing air into a space is an example of..

Question 8 of 10

9. How many BTU’s make up a ton?

Question 9 of 10

10. Decreasing Pressure will result in a _____ Boiling temperature

Question 10 of 10


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