Advice on Starting an HVAC/R Career - Short #98 - HVAC School

Search In:

Event Videos Tech Tips Apps Books Podcasts Users

HVAC Feed
Resources
Content
Courses
Events
Jobs
- Create a Job Post
- Job Posts
Shop
Partners

Search In:

Event Videos Tech Tips Apps Books Podcasts Users

+

Chinese (Simplified)

Get Tech Tips

Subscribe to free tech tips.

BACK

Advice on Starting an HVAC/R Career – Short #98

July 28, 2020

Print Friendly, PDF & Email

Share this Tech Tip:

Share this:

Facebook
X

Check out our most recent video

How to Evacuate an AC system, Full Vacuum Procedure

Our latest Podcast

HVAC School – For Techs, By Techs

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.

Audio Player

Roman SpeakPipe VRF – Short #235

HVAC School – For Techs, By Techs

Roman SpeakPipe VRF – Short #235

In this short podcast episode, Roman Baugh takes over the HVAC School podcast to answer a listener-submitted question about VRF (or VRV) system evacuation.Evacuation is[...]

0.8
1
1.2
1.5
2

Facebook
Twitter
Linkedin
Copy episode link Copied
Download

00:00

00:00

Roman SpeakPipe VRF – Short #235

byBryan Orr

In this short podcast episode, Roman Baugh takes over the HVAC School podcast to answer a listener-submitted question about VRF (or VRV) system evacuation.

Evacuation is a critical step of making repairs on VRF systems, which are very diverse and versatile but require a high level of understanding. VRF systems have multiple indoor units per outdoor unit, and they achieve that with the help of several components and accessories down the refrigerant line that can pose issues in evacuation and pressure testing.

In heat recovery units, some manufacturers use solenoid valves (or even electronic expansion valves) in branch selector boxes or branch collector boxes. These valves act as little traffic guards, and the system needs to be put in its refrigerant recovery or vacuuming mode. If not, then you won’t be able to evacuate all of the refrigerant and non-condensables from the system. Even if the system passes a decay test, contamination is a major concern when the system starts up and the valves open (due to nitrogen and oxygen mixing with pure refrigerant being put into the system).

You can trust and verify that the system is in its proper operating mode at the thermostat to ensure that the valves are open 100% and ready for evacuation or pressure testing. Failure to do so not only poses a contamination risk but likely won’t maintain its pressure during the pressure test. Assumption or trust alone is not enough.

Heat pumps only have two lines, and the vacuum pulls from both sides of the valve. There’s less of an issue because there are no branch selector or collector boxes, but it’s still good to ensure that the valves are responding and communicating.

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

Purchase your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium.

Subscribe to our podcast on your iPhone or Android.

Subscribe to our YouTube channel.

Check out our handy calculators here or on the HVAC School Mobile App for Apple and Android

Search Episodes

Roman SpeakPipe VRF – Short #235

04/08/2025

Bryan Orr

10 Things I’ve Learned In the Last 10 Years

04/03/2025

Bryan Orr

R290 as a Drop In? – Short #234

04/01/2025

Bryan Orr

Preventing Slugging & Flooding w/ Copeland

03/27/2025

Bryan Orr

What is the Best Brand? – Short #233

03/25/2025

Bryan Orr

Helping Small Owners Succeed w/ WorkHero

03/20/2025

Bryan Orr

MeasureQuick Talks with Bert

03/18/2025

Bryan Orr

Leak Detection Tech w/ Inficon

03/13/2025

Bryan Orr

Live from AHR with Kalos Team Dre & Elliot

03/11/2025

Bryan Orr

A Conversation with NAVAC at AHR 2025

03/07/2025

Bryan Orr

Search Results placeholder

Check our latest Tech Tips

Don't Drive Drowsy Flex Ducts: Peeling Back the Layers Solving Delta T

Nylog Blue Gasket -Thread Sealant for AC/R Systems

Nylog Blue Gasket -Thread Sealant for AC/R Systems
One drop of Nylog on your rubber hose gaskets prior to attaching your core tools, hoses or vacuum gauge will assure that things do not bind or leak during evacuation. Derived from refrigeration grade lubricants. Non-hardening, non-drying fluid which bonds tenaciously to many different substrates. Typically, one drop of Nylog can be stretched about three feet before breaking.

VENOM PACK CONDENSER PURE CONCENTRATE COIL CLEANER

VENOM PACK CONDENSER PURE CONCENTRATE COIL CLEANER
Venom Pack Condenser Cleaner is a high foaming pure concentrate liquid designed to tackle the toughest soils. The proprietary blend of specialty detergents will liquify heavily embedded grease and grime to restore heat transfer and increase the efficiency of the coil.

Viper Condensate Pan and Drain Treatment

Viper Condensate Pan and Drain Treatment
Viper Condensate Pan and Drain Treatment is a sprayable gel. It coats the pan, p-trap and drain piping with a lubricative film to improve flow and prevent future soil adhesion. The slow dissolving enzyme gel will outperform and outlast conventional tablets and strips.

Nylog Blue Gasket -Thread Sealant for AC/R Systems

Nylog Blue Gasket -Thread Sealant for AC/R Systems
One drop of Nylog on your rubber hose gaskets prior to attaching your core tools, hoses or vacuum gauge will assure that things do not bind or leak during evacuation. Derived from refrigeration grade lubricants. Non-hardening, non-drying fluid which bonds tenaciously to many different substrates. Typically, one drop of Nylog can be stretched about three feet before breaking.

VENOM PACK CONDENSER PURE CONCENTRATE COIL CLEANER

VENOM PACK CONDENSER PURE CONCENTRATE COIL CLEANER
Venom Pack Condenser Cleaner is a high foaming pure concentrate liquid designed to tackle the toughest soils. The proprietary blend of specialty detergents will liquify heavily embedded grease and grime to restore heat transfer and increase the efficiency of the coil.

Viper Condensate Pan and Drain Treatment

Viper Condensate Pan and Drain Treatment
Viper Condensate Pan and Drain Treatment is a sprayable gel. It coats the pan, p-trap and drain piping with a lubricative film to improve flow and prevent future soil adhesion. The slow dissolving enzyme gel will outperform and outlast conventional tablets and strips.

Nylog Blue Gasket -Thread Sealant for AC/R Systems

Nylog Blue Gasket -Thread Sealant for AC/R Systems
One drop of Nylog on your rubber hose gaskets prior to attaching your core tools, hoses or vacuum gauge will assure that things do not bind or leak during evacuation. Derived from refrigeration grade lubricants. Non-hardening, non-drying fluid which bonds tenaciously to many different substrates. Typically, one drop of Nylog can be stretched about three feet before breaking.

NAVAC

FROM AUGUST 2024 TO MARCH 2025 BUY NAVAC TOOLS FOR A CHANCE TO WIN A MOTORCYCLE! Any purchase of NAVAC HVAC Tools is eligible to gain entries for a Grand Prize of a Harley Davidson motorcycle.

NAVAC

Find out more about the Innovative NAVAC line of Vacuum Pumps

NAVAC

FROM AUGUST 2024 TO MARCH 2025 BUY NAVAC TOOLS FOR A CHANCE TO WIN A MOTORCYCLE! Any purchase of NAVAC HVAC Tools is eligible to gain entries for a Grand Prize of a Harley Davidson motorcycle.

NAVAC

Find out more about the Innovative NAVAC line of Vacuum Pumps

NAVAC

FROM AUGUST 2024 TO MARCH 2025 BUY NAVAC TOOLS FOR A CHANCE TO WIN A MOTORCYCLE! Any purchase of NAVAC HVAC Tools is eligible to gain entries for a Grand Prize of a Harley Davidson motorcycle.

Comments

To leave a comment, you need to log in.

Related Tech Tips

Finishing Trade School? Some Things you Need to Know Read more

Why the 20° Rule is Driving The Internet Crazy Read more

Manual J Field Data: Windows Read more

loading

To continue you need to agree to our terms.

Terms and Conditions

The HVAC School site, podcast and tech tips
made possible by generous support from

Interested in a HVAC Career?

Find A local trade school

Resources

Calculators
Tool list
Apps
Great Books
Software and Business
Other Resources we like
Unconformed

Content

Start
Podcasts
Videos
Social Media
Tech Tips
Quizzes
Courses

Events

6th Annual HVAC/R Training Symposium
Upcoming Events
Create an Event
Event Partnership

Jobs

Job Posts
Create a Job Post

Partners

Partners
Carrier
Copeland (Emerson)
ESCO Institute
Fieldpiece
NAVAC
Refrigeration Technologies
UEi Test Instruments

Get Tech Tips

Subscribe to free tech tips

Email Address

First Name

Terms and conditions & Privacy Policy
EULA
Reuse License

©2025 - HVAC School | All rights reserved