Ductless and VRF Diagnosis w/ John Chavez EP2

HVAC School - For Techs, By Techs

Bryan Orr

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

4.8 • 985 Ratings

🗓️ 12 September 2017

⏱️ 57 minutes

🔗️ Recording | iTunes | RSS

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Summary

What do you need to know to walk up and fix a VRF or ductless system? John Chavez, longtime VRF/ductless pro, covers his approach to ductless and VRF diagnosis in Part 2 of this podcast. (Listen to Part 1 HERE.)

If you believe that there is a component failure, you'll want to check the voltage going into the unit. You'll want to pay special attention to the board and see where power is going in and out. In other words, pay attention to your inputs and outputs on the board and pay attention to the documentation in the manual. Make sure you have a quality voltmeter on hand.

Another potential electrical issue occurs when the board blows out entirely. When that happens, you'll have to watch the input voltage and be mindful of the utility quality and local geography. Utility companies WILL NOT admit if they are part of the problem, so it is good for a technician to ask about the property and utilities to study the history of the unit and the location.

Watch your discharge air temperatures and make sure they perform correctly under AHRI conditions (the standard is 95 degrees outdoors, 86 degrees indoors); should have 40-50 degrees coming out of the discharge of the ductless unit. Pipes may even get as cold as 37 degrees before discharge protection kicks in.

To sum everything up about VRF diagnosis, you'll want to do whatever you can to find the root cause; don't be a parts-changer. To consider all possibilities, you must take your time to understand the unit.

We also discuss:

Lightning strikes and power surges
Determining delivered capacity
Critical charge
Electrical/controls terminology
Building science, thermal envelopes, and VRF performance
Sensible and latent heat loads
Inverter-driven compressors

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.
0:14.0	Testo, Rector Seal, and Carrier.
0:18.0	Condensate Overflow switches are very much under considered in both maintenance situations, service calls, and in
0:29.3	installations.
0:30.3	Technicians, they get used to installing them one particular way and then that's just they want to apply that rule to every single switch that they run into and different applications require different types of switches even in the unified mechanical code.
0:42.0	So James Bowman and I talk about that
0:43.7	a couple episodes back if you want to hear about that.
0:45.7	But Rector Seal is a leader when it comes to condensate
0:50.1	overflow switches.
0:51.4	They have the safety switch, they have the easy trap, and they also have
0:56.4	the aqua-gard lines all under rector seal and they all make different products that serve
1:00.7	different purposes. They have products that have the trap already installed that you can clear out and you can see the entire trap.
1:07.0	Even with the safety switch, the SS1, which is a switch that we've used for years, they came out with a clear-bodied version, so you can actually see what's in the switch,
1:15.2	which is pretty cool.
1:16.2	We use a lot of the SS2s, a lot of the SS3 pan switches.
1:19.6	They just have a really wide broad line, and when you look at Aquagard
1:22.8	Aquagard has some really neat innovative products.
1:25.0	They have one float switch that you can actually
1:27.2	unthread the cap from the bottom in order to get the water out
1:30.1	and check the float which is a nice design.
1:32.2	So there's a lot of different products that you can get through
1:34.2	rector seal in the condensage switch category, but the one thing that I want you to think about is next time you open up once,
	...

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