Ductless and VRF Diagnosis w/ John Chavez EP1

HVAC School - For Techs, By Techs

Bryan Orr

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

4.8 • 985 Ratings

🗓️ 9 September 2017

⏱️ 71 minutes

🔗️ Recording | iTunes | RSS

🧾️ Download transcript

Summary

What do you need to know to walk up and fix a VRF or ductless system? John Chavez, a longtime VRF/ductless pro, explains his approach in Part 1 of this podcast.

You CANNOT have a haphazard approach to installation or service. The best thing you can do is respect VRF and ductless technology for what they are. When you take the time to understand the equipment and the processes at work, you will be successful. The best thing you can bring to a job is patience.

Unlike on typical split systems, gauges should NOT be hooked up to a ductless or VRF system unless they are absolutely necessary. Gauges may introduce contaminants into the system, and they may cause more harm than good if techs use them when they are unnecessary. Superheat is rarely a useful diagnostic reading for mini-split and multizone systems. However, superheat and subcooling are readily available readings that may be useful for diagnosing VRF systems.

Diagnostic work requires detective work; ask questions about the system history to see how it has performed in the past. Involving owners in the repair process is a good way to build a relationship while understanding the problem better.

Like split systems, dirty coils and air filters can severely compromise a VRF/ductless system's performance. So, try to make sure filters and coils are all clean during diagnosis. The fins of evaporator coils can get especially dirty and should be cleaned. Some ductless systems can be cleaned in place.

Be sure to take down the model and serial numbers of the system. If you need tech support, you MUST have those numbers to be as specific as possible. Service and installation manuals are also useful tools for diagnosis (yes, we know that some techs are allergic to reading). However, don't over-rely on the error codes.

Resources

Computer Room Application Formula

Ductless Steps

Friedrich Service Form

Seven Common Install Answers

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Transcript

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0:00.0	The free training provided by the HVAC School Podcast is made possible because of the generous support from our sponsors.
0:14.3	Testo, Rector Seal, and Carrier.
0:18.3	All right, if you guys have listened to this podcast for any amount of time, you know that I kind of have a little bit of a
0:25.1	crush on the test of 605i. It's just a stupendous. Can I say stupendous and
0:30.0	not have it seem like hyperbole? I'm going to choose to say stupendous. It is a stupendous
0:34.6	tool for the investment that you spend on it. It is a great thermal hygrometer. And for those of you who are like,
0:39.8	what the heck is a thermogrometer? Well, let me tell you. A thermogrometer is basically a digital
0:44.8	psychrometer. That's another term for it. And it measures wet bulb, dry bulb,
0:48.3	relative humidity. At due point, you know, it can extract all of those if you've ever looked at a psych chart.
0:53.2	You need a couple pieces of information, then you can extract the rest.
0:55.7	But what the 605i does really well is that you can measure these readings in duct.
1:01.0	So you can take wet bulb, dry bulb, dry bulb, relative humidity in the supply,
1:07.0	and right there in the Smart Prob's app,
1:08.4	it will actually calculate delivered capacity
1:11.4	as long as you enter the CFMs, which is pretty cool, CFM.
1:14.4	I always want to say CFMs, CFM of air.
1:17.6	So the 605I is a great tool, but when you add in what Jim Bergman is doing with the Measure Quick app, which you can find out more by going
1:24.9	to measure quick.com forward slash download now on that application. You know I'm excited about that
1:29.2	product, but the Testo Smart Probes and the Testo 605i work with Jim Bergman's Measure Quick app.
1:36.0	And so you can get the best of both worlds.
1:38.0	A really, really highly functional app, plus the Testo 605i.
1:42.0	The actual Smart Probe app that you can use directly with the 605i,
	...

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