use compression type fitting on straight pipe?

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dabiz7

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I want to install a filter housing in my 3/4" supply line from the the main shutoff....I want to use a straight piece of 3/4" L type tube. Can I use compression style fittings with this type of tubing?

If I use a compression fitting instead of solder, I could take the housing out or replace it later with another style without having to cut and re-solder.
 

Krow

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Most plumbers would not dream of using a compression fitting in the line of 3/4 pipe.

Most plumbers will give you advise as if they were going to do it themselves. (I know I would). We also have to consider that a DIY'er may not have the tools to do the job professionally.

I personally would recommend to solder any and all 3/4" fittings
 

SteveW

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https://terrylove.com/forums/showthread.php?t=18752&highlight=compression


This poster seems to have gotten the message on this site that 3/4" compression connections are OK.

Why would compression valves/connectors/whatever be OK for smaller lines and not OK for 3/4"? Is it that 3/4 and larger is more rigid and less able/willing to deform when you tighten a compression fitting, and therefore more likely to catastrophically fail?
 

hj

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compression

No. It is because they are larger in diameter so any misalignment is magnified and becomes more serious. They are also subject to vibration problems for the same reason.
 

Krow

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With rigid pipe, there is always the potential to pull apart. (I'm not suggesting its going to happen) It could happen. I, as a plumber and tradesman, would NEVER consider using it on a rigid copper line, especially 3/4".

I can see it being used if shutting down the line completely is giving you a problem, but if it has the oppurtunity to be solderd, then thats what I would do..

For the DIY'ers, it would be the greatest invention ever made. Its just a personal preference for me
 

Bob NH

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Filters usually require a shutoff valve at the inlet.

Watts makes solderable valves that incorporate union-type adapters. I have bought them at HD.

One advantage of the union valve is that it doesn't require any axial displacement to disconnect the equipment.

If your idea of "compression fittings" is the "Dresser coupling" type that is often used for a repair coupling, you must be aware that the pipe must be fully restrained on both ends to prevent the joint from pulling apart.
 

SteveW

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I suppose another option would be Sharkbite fittings (although they do require some axial displacement).
 

Master Plumber Mark

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whats the matter with a comression fitting??

i have used 1/2 and 3/4 brass compression fittings
many times in the past.... nuts and ferrules work great

I usually carry an assortment in my truck for those nasty situations
where you absolutely cant solder becasue of a large amount of
water pissing down out of the pipes ---- down your forearms and into
your shirt .......and then out your pants leg......

occasionally this happens when changeing out a water heater
and you cant get the water to completley shut off or drain out of the system


their is absolutely nothing wrong with them
and they can save you mucho tons of greif , time, and misery.

and they have been on the market forever

All you have to do is use pipe dope on them and
crank them down as tight as possible.....

they are much , much easier to take apart than the shark bites too.....

and I trust them to last longer than the shark bites


they will work fine for what you want to do as long as you
have the forearm strength to tighten them to the extreme

its no big deal if you know what you are doing.....
 
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