Roman SpeakPipe VRF - Short #235

HVAC School - For Techs, By Techs

Bryan Orr

Training, Careers, Airconditioning, Self-improvement, Hvac, Business, Education, Refrigeration, Heating, Ac, Apprenticeship

4.8 • 985 Ratings

🗓️ 8 April 2025

⏱️ 9 minutes

🔗️ Recording | iTunes | RSS

🧾️ Download transcript

Summary

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.

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Transcript

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0:00.0	Hey, hey, hey, we have a question today.
0:07.1	What wait before I do that?
0:08.7	This is the HVAC School podcast.
0:10.4	I'm Brian.
0:11.4	This is the podcast that helps you remember some things you might have forgotten along the way
0:14.0	as well as helps you remember some things you forgot to know in the first place.
0:17.1	And today, we have a question from a listener about VRFVV evacuation.
0:24.1	And rather than me answering it, I'm going to have our in-house VRF VRV expert Roman Baugh answer it after this word from our sponsors.
0:34.3	Refrigeration technologies at refrigetech.com and specifically the new Viper Wetrag Heat Shield,
0:41.8	the revolutionary flame-resistant welding pad designed to be used either wet or dry.
0:48.6	Find a Viper wet rag heat shield at a distributor near you or go to TrueTechTools.com
0:53.6	and use offer code, get schooled for a great discount at checkout.
0:57.7	Fieldpiece, fieldpiece.com.
1:01.0	Santa Fe dehumidifiers in their new five-year,
1:04.1	complete replacement coverage.
1:06.9	Find out more at HVACR school.com slash Santa Fe.
1:11.4	Carrier.com.
1:13.4	I've been a carrier dealer for many years.
1:16.0	Carrier has their new green speed extreme, super high efficiency heat pumps out on the market now.
1:22.7	Find out more by going to Carrier.com.
1:27.2	Now here's the question.
1:28.7	Yes, Brian Hoare.
	...

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