Month: November 2016

wire_rubout

There are a few important things that I suggest checking on every service call to reduce callbacks and increase customer satisfaction. One of them that often gets missed is preventing wire rub outs.

One of my area managers and experienced tech Jesse Claerbout shot a video showing the simple step he takes to prevent major damage.

We also just release a new podcast episode today that you can hear in any podcast app or by listening HERE

Cheers!

–Bryan


In order to maintain combustion (burning) you need three things, fuel, heat and oxygen. If you have all three in the proper proportion you can maintain a continuous state of combustion.

Remove one (or reduce one sufficiently) and the triangle of combustion can collapse.

In a common NG gas furnace the heat is the igniter, the fuel is Natural Gas and the oxygen is provided by combustion air.

Combustion air is literally just the air needed to provide a continuous supply of air for proper combustion (burning).

All gas fired appliances must have both a flue / chimney to exhaust the leftover products of combustion (outlet) as well as combustion air to provide the oxygen for burning (inlet).

In high efficiency furnaces the combustion air is generally piped in, directly from the outside straight into the combustion chamber. This creates a dedicated source of oxygen and also a cleaner install as no other provisions need to be make for combustion air.

In 80% furnaces the burners usually have “open” combustion and they rely on air being drawn into louvers on the furnace cabinet. In this design the space on which the furnace resides must have open communication to the outdoors or other “uncontained” space.

Not to get into the specifics of code, but you must have a dedicated method to get significant air to the furnace . If you do not, the real possibility exists that the furnace could begin burning improperly creating an unsafe condition for the occupants due to Carbonmonoxide.

Different parts of the country provide combustion air in differnent ways, but you MUST have some method of providing unlimited fresh air to a furnace or to the room in which the furnace is located. This means when a furnace is in a tight space, ensure you have some sort of significant combustion air.

— Bryan


I walked in to my first real job interview in the A/C business. The manager was a guy named Ernie and he walked me out to the warehouse.

Quick warning.. guys named Ernie are tough. Don’t mess with dude named Ernie.

Anyway..

He walked up to a box, snatched a pen out of his shirt pocket and scribbled a circle, 3 dots and three numbers on it while grunting “which is common, start and run”

I was in luck….

While I may have had almost zero practical knowledge of air conditioning, this was one thing I HAD actually learned in school.

I marked the terminals and I got the job.

Before you say that this information is useless let me stop you. 

It isn’t useless. It may not be something you use every day, but I have needed to ohm out a motor or compressor a handful of times and it got me out of a pinch.

So here it goes

The lowest ohm reading is between Common and Run

The middle ohm reading is between Common and start 

The highest ohm reading is between start and run

Common is just a point between start and run and therefore the common to start and run to start readings will add up to the run to start reading.

Here is how I remember this (let the mockery begin)

Starting is hard… so it has the highest resistance 

Running is hard also… but not as hard as starting, so it has a resistance less than start.

Common is easy… being common requires the lowest resistance

So common to run is the least and start to run is the most.

Understanding common, run and start is uncommon… so it requires a lot of resistance… so start… knowing it

OK I’m done. 

Happy Thanksgiving ? 

— Bryan

electrical-theory

In this episode of HVAC School, Bryan talks to his boys about basic electrical theory and they talk about:

  • Differential Charges
  • Electromotive Force
  • Ohm’s Law
  • Volts, Ohms, Amps and Watts
  • Electrical paths
  • Conductors and insulators
  • Resistive and Inductive loads

And Much more…

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

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