No readers? No lurkers? No smarter Techs cause they read the info?

 

Some of us just instinctively know that all.

 

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I love this stuff, it’s like finding gold when you come across it. Thanks!


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CAPILLARY TUBES-THEORY AND PRACTICE" by Henry Ehrens is a very instructive read and I handed out copies to all my refrig students. Most of which were probably ignored..

Explains how a "fixed orifice" in the form of a long tube has (some) capacity control unlike a flowrater.

 

I have that and just now downloaded it again, thanks to pecmsg. I have many great downloads thanks to you, sir!
And hey Techman! I have a list of books that you posted a yr or two ago but its lost on my phone flash card like everything else. I remember one of them goes back to the 19th century. I recently bought the Carl Geist book for $5 and am glad I did. Now, Wirz' Commercial Refrig is peerless but I pure-dee hated that "Modern" textbook I was required to buy used for $75 in 1997.
I wouldnt mind having that list again, Techman when you have the time please, sir. You can can send me a pm if you want to.
Thanks, Jimmy

 

If you get it may i also have a copy?

 

I am going to claim "asleep at the wheel" here,lol,Gents.
Jim1959, can you let me know what the subject was,concerning that list of books? I have lots & lots of books on lots & lots of HVACR subjects and sub-subjects. I will be happy to help.

 

I knew from reading your posts Techman, you were too busy workin'!
It was a list of old books bec I had talked about that in a post but they weren't on any one subject. Don't worry about it for now, anyways.
Thanks, brother!

 

Hi Jim, I'll post some old book titles later as I'm out the door to go to work at 0600.

 

Sounds good. Funny thing is how many of my peers arent even and wouldnt be interested in reading even though theyre in the field. I have an obsession for refrigeration related things whether its looking at old ice boxes or reading old literature. No matter how far we advance the basics are always still the same. Fascinating!

 

I stumbled across this just browsing some refrig posts.

What's the balance test the author talks about for checking balance of an unknown cap tube? I'm trying to wrap my head around it.

He changes the strainer. He hooks a gage to the hi side port. Then I'm lost. Does he install a drier on the suction service port, pulling in ambient air for the test?

It is some great information on cap tube systems. I'll have to pull this document next I'm on a cap tube system and see if it helps me process things better in my head. Thanks for the information!

 

The cap tube balance tester is intended to be used for testing the captube to see if it's partially plugged up, for testing the capacity of the cap tube compared to the capacity of the compressor as well as for testing the compressor for pumping efficiency.

The strainer he refers to is installed at the low side service port to filter the air being drawn in for the test. I've attached a diagram of the test setup below. Yes, it uses ambient air for the test.

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The balance tester is nothing more than a low-side pressure gauge with the scale indicating temperature ranges for low medium and high temperature systems. He never says what the pressures are, but I suspect since I believe he did much of his experimentation back in the 1950's and 60's using R12, you could use your PT chart to come up with reasonable pressures to expect for any refrigerant.

Here's a link to a slideshow I made of the original user manual for the Supco balance tester:
https://icemeister.net/backroom/wp-content/uploads/2020/01/Supco-Compressor-and-Cap-Tube-Tester.pdf

 

Thank you so much for the post...
This is so helpful... Gonna make it a point to read all these resources.

 

So much info/knowledge needed for just a stupid piece of "copper tubing", Cripes. But once I understand ALL of that info about a cap tube I have never looked at a roll of 3/16, 1/4, 5/16, 3/8,7/16, 1/2, 5/8,3/4,7/8 & 1 1/8 ACR copper w/o thinking, HOLY MACKEREL!lol.

 

Probably the most useful capability of the Supco Balance Tester is you can install a new cap tube and test it to see if it properly balances with the compressor capacity. If the test pressure is too high for your application just cut off 6" to reduce the restriction and test again. If the pressure is too low, then the cap tube is too short.

The principle behind the tester is quite simple. It draws its air charge from atmospheric pressure. As long as the pressure at the low side port is below atmospheric, it will draw in more air. When it's equal to atmospheric, the air charge is complete and the system pressures should be steady with the flow through the cap tube equal to the flow being pumped by the compressor.

Since when the system is balanced, the compressor suction would always be at atmospheric pressure. So the compressor's discharge pressure will give you a relative reading on whether the installed cap tube size would be in the ball park for a freezer, cooler or air conditioner with that compressor.

 

A member posted pics of his supco tester before...

Maybe it wasn't here I can't remember.

 

I cant seem to find 620-43 anywhere. Anyone have a copy?