Reversing Valve Diagnosis & Replacement w/ Kaleb

HVAC School - For Techs, By Techs

Bryan Orr

Education, Business, Self-improvement, Careers

4.9 • 1K Ratings

🗓️ 16 January 2020

⏱️ 34 minutes

🔗️ Recording | iTunes | RSS

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Summary

In this face-to-face discussion, Bryan and Kaleb share some tips for diagnosing and replacing the reversing valve on a heat pump. These valves may also be known as four-way valves.

Kaleb and a trainee recently had to diagnose a heat pump with a scroll compressor. The motor was also over-amping due to a failed capacitor, and the compressor was making a metallic grinding noise. Because reversing valves are pilot-activated, they need a pressure differential to shift, so the scroll plate can sometimes pop up and make noise during bypass. Another possibility was that the compressor could have been running backward, but that wasn't the case.

There are some cases when techs misdiagnose a compressor problem as a reversing valve failure; however, in Kaleb's case, there was a problem with the reversing valve that then caused compressor failure.

To determine if a system has a reversing valve issue, you should look at the temperature difference across the valve (more than 3 degrees). Another thing to look for is an abnormally low compression ratio (high suction, low head pressure). You also want to watch the compressor amperage, as it will likely be lower than normal. When doing more advanced tests, such as delivered capacity tests, use Bluetooth tools to make your life a lot easier; that way, you can clamp your probes on.

When Kaleb replaces a reversing valve, he cuts them out wherever possible. If he can't cut them out, he sweats them out and sweats the new one in. Sometimes, it's also easier to remove the entire condenser coil during replacement.

Kaleb and Bryan also discuss:

Common suction port
Causes of compressor damage
Unreasonably hot discharge lines
Compressor amperage drop
Common suction, common discharge lines
Kaleb's compressor replacement
Cutting out suction dryers
Sweating out reversing valves in Trane units
Purging with nitrogen before a pressure test
Deburring properly

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Transcript

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0:00.0	This episode of the HVAC School podcast is made possible by our sponsors and our sponsors
0:09.3	are carrier and carrier.com. Carriers have been a long time partner with HVAC school. Thank you to all of those great folks over at carrier.
0:17.0	Refrigeration Technologies at Refrigerate.com. The Pasture Nylog, which is what we use on our threaded connections in the
0:27.1	refrigerant circuit made of a virgin oil.
0:29.6	Little dabbled do you, a Semberly lubricant helps to seal especially under vacuum those really
0:34.7	really tiny leaks that can drive you crazy when you're noticing decay under
0:38.3	vacuum the flares and chattler fittings and air equip fittings those sorts of things so
0:42.2	we use Nylog from refrigeration
0:45.6	technologies as well as all their Viper Cleaners. And one of our favorite Viper products
0:49.6	is the pan and drain treatment spray that we use especially on ductless systems.
0:54.5	It really helps to reduce the odors on ductless systems.
0:57.7	At least it seems to have tested it quite a few times.
0:59.7	I've been very happy with it even on my own home.
1:02.1	That is the pan and drain treatment from
1:04.6	refrigeration technologies. Find out more at refrigerantec.com. Also speed clean
1:09.0	speed clean. speed clean makes the coil jet. Boil jet is a self-contained unit where you have the water and the cleaner and the battery all on board.
1:18.0	It's an orange tank. You've probably seen one.
1:20.0	They put them together up in Connecticut and they have a really great quality control process up there. I visited their factory.
1:27.0	I'm a big fan of that particular product and we have a whole bunch of them at Kailalo, a bunch of the coil jets.
1:33.0	You can find that at truetech tools.com, TRU tech tools.com, using the offer code
1:37.8	get school to at check out for a great discount or go to speed clean
1:41.2	com to find out more and while you're at it
	...

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