Changing from Compression to Flare Oil Line Fittings

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  #1  
Old 10-24-16, 10:17 AM
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Changing from Compression to Flare Oil Line Fittings

Our oil fired furnace was hooked up (in 1989) with compression fittings and they did not use L type 3/8" ID copper tubing, rather it is 3/8" OD line.
I was planning to switch over to flares and purchased 3/8" type L tubing only to find that it was not the same diameter as the rest of the line.
First question, are the flare type fittings for L type different than for regular 3/8" OD line? What are they called?

Should I even bother if they have been working fine since 1989 and the lines from the tank are not even L type?
 
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Old 10-26-16, 09:33 AM
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Found this but it discusses gas and water fittings, not sure if oil type are the same:
https://www.copper.org/applications/..._8flrdjts.html

I should probably leave this for the professionals to do.
 
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Old 10-26-16, 10:50 AM
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3/8 inch nominal inside diameter would be copper pipe. 3/8 inch exact outside diameter would be tubing. ALL flared fittings are sized to the outside diameter tubing. Flares can only be made on soft temper (annealed) tubing. Tubing is sometimes referred to as refrigeration tubing, especially when the inside has been specially cleaned and the ends crimped or capped.
 
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Old 11-04-16, 05:22 PM
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The type L tubing that I was able to find at Lowes is 3/8" ID, and it is slightly bigger that the tubing that is already installed. Here is what I bought, it does not state if the 3/8" is ID but that is what it said on the shelf:
https://www.lowes.com/pd/3-8-in-dia-...r-Pipe/3134485
 
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Old 11-04-16, 07:12 PM
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Pete
First off, all copper is measured by OD. Steel or Black Iron is ID. Oil line in 89 is oil line today. It is and has been 3/8 OD. Until recently the term L tubing was never used. They only sell 1 thickness of oil line.
That being said you may want to check with the Fire Dept. about the latest code for installing the line. I don't know about CT but in MA all oil line has to be sheathed. At one point you could put it in a sheathing now it comes already encased. I only mention this to possibly save you work that will not pass inspection anyway.
They require flair in place of compression now because compression tend to leak over time.
 
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Old 11-06-16, 06:04 PM
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Thanks for the input/help but they had both types, L and non-L, both 3/8"
and the sizes were slightly different. I'll have to go back, look closer and
take a picture because I understand that you guys are the experts, but
that threw me off.
What I purchased is not the same size as what is already there.
 
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Old 11-06-16, 06:43 PM
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The only answer I have is they may be buying some off-sized or possibly metric "equivalent" (yeah ) made in a Communistic Asian country rather than American made tubing. It should make no difference if it is type K, type L or type M, it is ALL measured by outside diameter.
 
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Old 11-06-16, 07:58 PM
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Pete,
I don't know how to respond to that because all copper is measured in OD. Your oil filter connections are 3/8". Look to see if they reduced down for some reason. They sell rolls of copper tubing from 1/8" to 7/8" in increments of 1/8's. Maybe the company just used what they had. Other than that I have no answer. I was thinking that line that you called 3/8" ID could have been 1/2"OD. Maybe mismarked.
 
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Old 11-09-16, 04:15 PM
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Thanks everyone, I will look into this a bit more and get back here.
 
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Old 11-14-16, 05:46 PM
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I beg to differ with the others on tubing sizes. Refrigeration tubing is measured outside. Plumbing tubing is labeled by inside. 3/8" refrigeration copper is the same as 1/4" plumbing copper. Both are 3/8 outside & 1/4" inside. If the tubing is labeled "Type ACR" it is refrigeration copper. Types K, L, & M are plumbing copper.
 
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Old 11-17-16, 03:10 PM
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Thanks Grady,
Okay, I have the box here with me, it is JMF Company:
Copper Coil
For use with: Solder, Flare, Compression, Push to Fit

On the side it says:
3/8 ID Type L
43501

Web site: JMF Company - Copper Tube

I'll try to find my micrometer and measure what is there now.
 
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Old 11-17-16, 05:44 PM
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What you have is 1/2" OD copper tubing size.
The link refers to it as 3/8"" pipe diameter which is it's ID, not OD.

Flare fittings are referred to by the OD tubing size.
A 3/8" flare nut fits 3/8" OD copper tubing.
The tubing you have will use a 1/2" flare nut.
 
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Old 11-18-16, 06:41 PM
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Thanks, I just wanted to make sure that I buy the right tubing, I know that L is better but I'm just going to match what is in there now.
Going to return what I have and give 1/4" ID a try, I'll measure first and then measure in the store also.
 
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Old 11-18-16, 07:05 PM
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Copper tubing
From Wikipedia, the free encyclopedia

Jump to: navigation, search
If you go to this page it will give you the measurements you're looking for. Tried to copy & paste but it was difficult to read the way it came out.
Hope this helps.
 
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Old 11-18-16, 07:12 PM
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United States[edit]
Common wall-thicknesses of copper tubing in the USA are "Type K", "Type L", "Type M", and "Type DWV":[2]
Type K has the thickest wall section of the three types of pressure rated tubing and is commonly used for deep underground burial such as under sidewalks and streets, with a suitable corrosion protection coating or continuous polyethylene sleeve as required by code. In the United States it usually has green colored printing.
Type L has a thinner pipe wall section, and is used in residential and commercial water supply and pressure applications. In the United States it usually has blue colored printing.
Type M has an even thinner pipe wall section, and is used in residential and commercial water supply and pressure applications. In the United States it usually has red colored printing.
Type DWV has the thinnest wall section, and is generally only suitable for unpressurized applications, such as drains, waste and vent (DWV) lines. In the United States it usually has yellow or light orange colored printing, common sizes being 1-" , 1-", and 2" copper tube size.
Types K and L are generally available in both hard drawn "sticks" and in rolls of soft annealed tubing, whereas type M and DWV is usually only available in hard drawn "sticks".
In the American plumbing industry, the size of copper tubing is designated by its nominal diameter, which is  1⁄8th inch less than the outside diameter. (This nominal diameter does not match any other physical dimension on the pipe; it may be larger or smaller than the inside diameter depending on the size of pipe.)
The American refrigeration industry uses different copper pipe called ACR (air conditioning and refrigeration field services) pipe, which is sized directly by its outside diameter (OD) and a type letter indicating wall thickness. Therefore, 1*inch nominal type L copper tube and  1
*
1⁄8th inch type D ACR tube are exactly the same size with different size designations. ACR pipe is manufactured without processing oils that would be incompatible with the oils used to lubricate the compressors in the AC system.
Except for this difference between ACR (types A and D) and plumbing (types K, L, M and DWV) pipes, the type only indicates wall thickness and does not affect the outside diameter of the tube. Type K  1⁄2 inch, type L  1⁄2 inch, and type D  5⁄8 inch ACR all have the same outside diameter of  5⁄8 inch.
 
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Old 11-20-16, 05:32 PM
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Thanks, that helps a lot, I think I get it now.
 
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