Q1 2017 ESPCO Newsletter


WHY NO HIGH-SIDE SERVICE PORT ON A MINI SPLIT? This is probably the most common question I get in my mini split training classes and one that the industry…and myself for that matter…hasn’t done a great job answering. I’m going to attempt to change all that right now…

First, we have to review what some may think is elementary and rudimentary, but I feel strongly that I need to lay a basic foundation so I can eventually get to the bottom of this.

Let’s take a look at what the expansion valve does to system pressure…

The expansion valve…in the case of a mini split, an Electronic Expansion Valve, takes in high pressure liquid refrigerant and discharges low pressure liquid / vapor refrigerant.

OK…now let’s see how this works in a “standard” refrigeration system where the expansion valve is located in the fan coil unit / evaporator.

In this case, the system has a clearly defined high & low side which can be accessed at the TWO service ports (suction & liquid), of the outdoor unit. Because the expansion valve is in the fan coil / evaporator located INSIDE the home, the suction service port will display low pressure and the liquid service port will display high pressure.  This is why standard outdoor units have TWO service ports.

The mini split however, places the expansion valve in the outdoor unit and that changes EVERYTHING!

It shifts the low pressure / high pressure border to WITHIN the outdoor unit. The high pressure side is now ONLY represented by the internal piping between the compressor discharge and the expansion valve inlet.

You know what this means don’t you?

Now, what has commonly been known as the suction (low pressure gas), valve and the liquid, (high pressure liquid), are now BOTH low pressure gas. Even if the mini split had a second service port on what is commonly called the liquid, it would display essentially the SAME pressure as the suction service port because it is located downstream of the expansion valve outlet.. which as described earlier…takes in high pressure liquid and discharges low pressure liquid / vapor.

I had a gentleman in one of my recent classes say to me, “look, the compressor still has a suction and discharge so there has to be a high side.”

He is right…the problem however is that the high side discharge tubing coming off the compressor is internal to the outdoor unit and only about a foot or two in length between the discharge of the compressor and the inlet of the expansion valve (of course the condenser is between the two).

Remember, the connection on the outdoor unit for the liquid, (although it’s not liquid), is downstream of the expansion valve outlet…so its LOW pressure gas / liquid!

I have seen a mini split outdoor unit that did provide a Schrader valve on the high side piping internal to the outdoor unit’s cabinet…only accessed by removing an outer cabinet panel.

I consider this a novelty at best…

If you want to see the high side pressure on a mini split it’s really easy to do…simply place the system in the HEAT mode…COME ON!


MONEY IS NOT THE ROOT OF ALL EVIL…JEALOUSY AND ENVY ARE! If you’re looking for more technical HVAC stuff…this article ain’t it. One of the benefits of creating this newsletter is it gives me an outlet for more than just my HVAC life…this article is about life in general.

My 55 years has given me many insights and one that I feel strongest about is jealousy and envy are the root of all evil.

Let me explain…

The nature of where my career has taken me in the last couple decades has put me out in the public eye a bit more than the average guy…maybe the HVAC industry’s eye is a more accurate description. As a result, some years back, I had been the object of someone’s jealousy and envy that, for a time, caused me to have to address what was a completely fabricated and inaccurate statement made about me.

Look…I’m not going to relive that very uncomfortable event with you here…that’s not what this article is about. What I do want to address is the root cause of the event… time has given me the clarity and wisdom to now see that its roots were in jealousy and envy.

I have a dear friend going through a very different type of episode right now yet still based, I believe, in someone’s jealousy and envy of him.

I admittedly have had difficulty understanding why some people become so interested…and ultimately, angered and consumed by someone else’s success and / or possessions. I have not been jealous or envious of someone, or their possessions, since I was a child. As an adult, I certainly admire others and their success and I can certainly admire someone’s car…their home…their business…but it is just that…ADMIRATION, not jealousy or envy. I am truly happy for the person and if anything, I want to talk to them and possibly learn from them.

My buddy who is in the depths of a very unpleasant situation is a very successful young man…VERY successful. The nature of his work puts him in the public eye…the overall public eye.  Someone has questioned his success and questioned his integrity, in my opinion, clearly out of jealousy and envy of his success, happiness and possessions.

The electronic world we live in where blogs and websites allow for anonymous judgements and attacks on character only gives these people a vehicle to propagate their attacks and accusations. I am always blown away how some find it so easy to call for someone’s firing or leave derogatory and often false statements about people they don’t even know, seemingly without any thought or concern that the subject of their post is a human being with a family and bills to pay just like everybody else!

The old saying that “money is the root of all evil” is just wrong on so many levels.

Money is a good thing…I believe what the character, Gordon Gekko, in the movie Wall Street said is true…”greed is good.”

I say that somewhat tongue in cheek but I do believe a healthy desire for success and all that it brings is a VERY good thing…it motivates…it inspires…it drives!

In my own experience and in what my friend is experiencing, money DID have something to do with it for sure…it was the jealousy and envy of my and my friend’s money, our success, possessions, etc.

And in my case, it was someone’s perception of my success…they didn’t really know me, they didn’t know how I EARNED my success and the fruits of that success…but they were jealous and envious of it and it consumed them. Instead of my success motivating them, it angered them…and this obviously says much about the character of my protagonist.

My success, or again, perceived success, only brought into light this person’s own failures and unhappiness and if I was successful and happy, well, in that person’s mind, I must have done something wrong to get it. I believe this is a common trait in all who become angered and consumed by jealousy and envy of someone else.

How sad…

I have purposely not used the word victim in describing myself or my friend…although the word’s definition does have some meaning in this context, I will not allow myself to be a victim. My life…my character…my integrity is what ultimately prevailed in my case and I’m sure the same will be true for my friend.

Why did I write this article? What purpose does it serve?

Admittedly for me this might be what some call “closure.” I have been thinking about addressing this subject in some way for years now so it may simply be that for me…closure.

I never for one moment thought this article could save someone else from what I experienced …I got a pretty good ego but it ain’t that big. My goal here is completely self-awareness and self-improvement. I don’t EVER want to be the person on the other side of the story…the one that is jealous and envious.


See you soon!

The views and opinions expressed in this newsletter are those of the author and do not necessarily represent those of ESPCO’s sponsors and training partners.