Purge Your Hoses

By July 10, 2017

The title says it all. It should be one of the first things you learn when you started. However, I have seen a lot of experienced techs who seldom (if ever) do it.

When connecting to a tank, purge your hose by cracking the center connection at the manifold for a second.

When connecting to a system, crack each connector for a second and then tighten. (Unless you are using ball valves or low loss of the same refrigerant type.)

Low loss brings up a different subject. If you are using them, you need to make sure not to switch between refrigerants without recovering all the refrigerant from your gauges.

Both air and incorrect refrigerant are not acceptable to add to the system, even in small quantities.

—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

John

4/4/23 at 06:51 PM

Is purging necessary if you are simply checking pressure and not opening to the manifold? I’ve been told it is not and that the air in your hoses cannot flow out of your hose and mix with the refrigerant in the system.

Roman Baugh

4/10/23 at 06:41 PM

The concern is less about the mixing of air (which is possible if you accidently open your high side to low side) and more so for the amount of moisture that is present in the air that is trapped in your hoses. Remember that moisture migrates and POE oil is hydroscopic. Reducing the risks (purging your hoses) of moisture contamination within the system should always be the standard practice.

Related Tech Tips

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. […]

It Has a Flat For a Reason

When tightening down a blower wheel or a fan blade on a motor shaft, ONLY tighten it on the flat of the shaft. If you have more than one screw but only one flat surface on the shaft, only tighten the one set screw. Also… Refrain from over-tightening set screws; they need to bite into […]

What are Dry and Wet Contacts?

I was talking about dry contacts with one of my techs, and he looked at me like I had three heads—and one of them was on fire. So, I figured it would be good to cover the difference between wet and dry contacts in a tech tip. Basically, “dry” contacts are switches with no shared […]

More tech tips