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Website owner: 
Dave Harnish
CEO: Gracie (RIP 3-16)
Dave's Repair Service
1911 Heath Hill Rd
New Albany, PA 18833
Email:
drs@sosbbs.com


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The DRSNews
April/May 2007


I apologize for the missing April issue, guys. The company that emails this out for me went down in late March, and with NO customer service (!), it took a while to get back up and running. (Needless to say, I’ve switched companies!)

 

By subscription only, Dave’s Repair Service
©2007 All Rights Reserved

Could you do me a favor, please? I’d really appreciate it if you would help me build our subscriber list. Please don’t forget to invite your friends to subscribe to The DRSNews!

Just forward them an issue with a note telling them why you like it, and/or send them to www.DavesRepair.com . Thanks!

(Scroll to the end to unsubscribe at any time)

***************************************

A Special Welcome if you've just joined us! What a great group of friends I've been making with this project! You guys are a tremendous encouragement to me! Thank you!
 

In this issue:

1) Refrigeration System Recharging Basics, Part 3:
    Leak Repairs
2) Trading Crosses
 

Don't spend all that money on 'OEM' ink! The Best
inkjet cartridge prices ever - at least for our Epson
printers (Used to pay $30 for inkjet cartridges - now
I pay $3.95!) You'll love these guys! I've used their
ink in all our printers for the last 4 years, and highly
recommend them:
 Inkjet Cartridges and Toner
 

1) OK, it’s been way too long! Let’s get back to talking about refrigeration system repairs. (Note: this series is just a quick overview. We’re just skipping stones over the surface here, but hopefully it’ll be of help to you)

(I hope to eventually publish these articles in one e-book to make it more convenient, and so we can go into more details
of these procedures)

Last time, we briefly discussed figuring out whether your system’s leaking or restricted, and some methods of locating refrigerant leaks.

Thought I’d get into some of the basics of the actual repair procedures this time, and how they relate to where the leak’s located. 

Before we proceed, let me mention two things:

I’m assuming some degree of technical expertise on your part here, and am obligated to point you to my disclaimer. Messing with refrigeration systems involves heat, pressurized gases, and other ‘fun’ ways to hurt yourself! Be careful!

Today’s refrigerants are highly hygroscopic, that is, they readily absorb moisture from the atmosphere, and moisture’s one of several ‘baddies’ (along with air and dirt!) that you can’t have in a system. Which means you want to complete this job as quickly as possible, without exposing the system to the atmosphere any longer than absolutely necessary.

That’s the #1 reason I recommend that modern refrigerant system repair is one of the few jobs better left to a pro. It takes experience to be able to do one of these fast, and a system max open time of 20 minutes is the number I shoot for. Not easy to do your first time. Hard enough to do after several decades of experience!

Most leaks occur at tubing joints, and the trickiest ones are where dissimilar metals are joined. Copper and aluminum don’t ‘like’ each other, and for many years now they’ve been connected together, most often in the evaporator coil inside the freezer section, where the temperatures swing from below zero F to 50 or 60 F. 

(I should mention that copper/aluminum connections aren’t usually soldered, but other methods are used to join them, like epoxy, o-rings, crimp connectors, etc. )

All that expansion and contraction makes it really tough to maintain a sealed connection between two metals with different expansion rates. And there’s plenty of moisture present to aggravate corrosion, so everything has to be done perfectly for the joint to last.

You’ll also see leaks down in the compressor compartment, and, although not as tough to repair, you’ll usually find two metals, steel and copper, connected together there, too, and getting leak-free connections on the first try can be challenging.

Leaks can occur inside cabinets as well, often in what’s called the ‘Yoder Loop’. These leaks can be hard to diagnose, and unique methods are used to repair them, but that’s a subject for another article.

Most systems are brazed at the factory, but even though many servicers repair them using brazing, I’ve always ‘silver soldered’ my jobs using lead-free low temperature silver-bearing solder. This is a lot like the old 95/5 solder we used in the ‘old days’, and one reason I’ve used it and like it is the relatively low temps required.

When we used to braze joints, I didn’t like the damage all that heat caused to the surrounding components, and I’ve found that it’s really not necessary.

I still have quite a few ‘soft-soldered’ systems operating here in our area that were recharged 20 years ago or more, including one of my own freezers, and they continue to perform perfectly.

This is getting long, so let me just leave you with some tips to soldering good tubing joints (these apply to water piping, too):

A) No pressure in system: before starting, be certain all refrigerant is out of the system, and that it’s open to the atmosphere. Any pressure buildup inside - and it can build from torch heat - will ruin the connection, and you’ll have to start again.

B) Cleanliness: you cannot have a joint too clean! Before soldering, sand it until it sparkles, and wherever there’s an insert tube, sand its OD and before inserting it, clean the larger tube’s ID with a stainless steel tubing brush sized to it.

If the tubing cutter left much of a ‘burr’ on the inside, carefully drill it out with the proper sized drill, then briefly vacuum the tube end to be sure no drill shavings found their way inside, where they can cause trouble.

For sanding tubing, I recommend a cloth emery paper roll called SandScreenä, another product that’s superior to any other I’ve tried over the years. It used to be marketed by Gemline, now out of business, but most refrigeration supply companies still carry it.

C) Swage it: rather than connecting a joint with couplers, I swage the copper tubing to make the connection. That eliminates one joint, which means there’s one less potential leak site)

D) Even Heat: I use a dual tip acetylene torch, which makes it easy to surround the tubing with flame, and heat the area evenly. Another benefit of two opposed flames is heat containment within a small area. This is indispensable when working in today’s tight compressor compartments, with all the heat-sensitive plastic and rubber parts nearby.

E) The Right Flux: I’ve tried nearly all of them over the years, and IMO there’s only one flux to use. Stay-Cleanä liquid flux, made by the JW Harris Co, does an exceptional job of preparing copper and steel tubing to receive soft solders, and I highly recommend it. It can be hard to find, but accept no substitutes! It is corrosive, though, so one of my last steps in a system job is wiping up any flux spills with liberal amounts of water. While a joint’s still warm, wiping it off with water will clean off any excess flux and make it shine, preventing future corrosion.
 

Here's the best flux I've ever found. I've used it for many years, and it's never disappointed.

I keep it in one of my "precision oiler bottles", which not only works well at putting a tiny drop of oil right where it's needed, but also happens to be a terrific way to apply this flux!

Stay-Clean flux & applicator bottle


By the way, be sure to heat the joint a bit first, then apply the flux. I think that one tip, learned the hard way, has improved the quality of my small diameter ‘pipe fitting’ at least 10-fold.

I’ll have to end there for now. We’ll continue this next time.

2) I’m facing some new challenges right now (who isn’t?), and here’s one that really helps me to keep it all in perspective. I know it’s ‘off-topic’ (maybe not the first time that’s happened in this newsletter, ha, ha!), but thought I’d include it, because I’ll bet you can relate…

A young man was at the end of his rope, and, seeing no way out, he dropped to his knees in prayer

"Lord, I can't go on," he said. "I have too heavy a cross to bear."

The Lord replied, "My son, if you can't bear its weight, just place your cross inside this room.

Then, open that other door and pick out any cross you wish."

The man was filled with relief and said, "Thank you Lord," and he did as he was told.

Upon entering the other room, he saw many crosses; some so large the tops were not visible. Then, he spotted a tiny cross leaning against a far wall.

"I'd like that one, Lord," he whispered. The Lord replied, "My son, that is the cross you just brought in."

When life's problems seem overwhelming, it helps to look around and see what other people are coping with. You may consider yourself far more fortunate than you imagined.

***

Thanks again for inviting me into your inbox. I don't take the invitation lightly, and please rest assured I will never share your name or data with anyone!

As always, if you have any topics you’d like to see discussed here or covered in an online article, let me know and I’ll do my best to oblige. And don't forget to send me a testimonial (I'll bribe you for one! <grin>) Many thanks if you already sent yours in!

May God richly bless you and yours,

Dave Harnish
Dave’s Repair Service
New Albany, PA
drs@sosbbs.com
http://www.DavesRepair.com
 

"When you were born, you were crying and everyone around you was smiling. Live your life so that when you die, you're the one who is smiling and everyone around you is crying."

Matthew 6

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Copyright 2007, www.DavesRepair.com , All Rights Reserved.
This newsletter may be reprinted and distributed freely, but only in its entirety, including this message.  

 

 

 


"Nothing astonishes men so much as common sense and plain dealing" - Ralph Waldo Emerson

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