Professional Member
What are the results of using old tubing from an R-22 system that is being converted to 410A? I have been able to use new tubing until now, where it is very impractical. Supposedly you can flush the existing tubing to remove the mineral oil. What have been the results in the real world?
Professional Member
unless theres somehow an excessive amount of oil in the lines, you don't need to do anything different than you would if swapping out R-22 equipment. mixing the oils doesn't create some sort of super sludge like the flush companies want you to believe.
Regular Guest
Make sure you confirm the size of the line set!!! also make sure you use the flush.
Professional Member
I worry more about the flushing agent than I do the oil so I dont flush unless its a burn out.
Professional Member
Experience counts. You guys feel like this is a concensus everywhere? If your experience and that of your peers tells you that there are more imprtant things to worry about, then I won't get too concerned about it. They said a lot of things about 410A in the beginning. I like this one: Do not charge vapor. Do not top off. Then they report that testing has shown that a leaking system can be topped off something like 35 times with no noticeable effect. Love the internet.
Professional Member
Just verify the line sizes are correct for the new equiptment. Do a tripple evacuation.
Member
Don't forget to change FD.
God Speed, Jim. We'll miss you - 2-26-23
Make sure line set size is ok. Then blow it out with nitro.
Its still best to only charge r410a as liquid only.
The false rumor you heard about not topping off was from sourves that either didn,t have any training on it, or were just prejuctice against it.
Professional Member
nearly all the linesets here are behind drywall so replacing them is not an option not to mention most people wont pay extra for them to be replaced.
Professional Member*
I just blow with nitro and pull a good vac with a micron gauge. When we first started installing 410 we used the flush but I feel like it will do more harm than a little oil. That flush is some potent stuff, smells like nail polish remover and burns your eyes. Trane install manual says to NOT use ac flush
Professional Member*
how would trane know.... lol
it was working.... played with it.... now its broke.... whats the going hourly rate for HVAC repair
Regular Guest
I would make sure there are no soft solder joints in it first!Back in the day , alot of installers used 50/50 or 95/5 on there joints! 410a pressures may cause a failure at this type of joint! Nitro flush is is a minimum prep.
Professional Member
A 3/8 line with 400 psi inside is experiencing about 17 pounds of force pushing the connection apart. Bubble gum would almost be capable of holding that together.Originally Posted by Mark s
Regular Guest
http://www.descoenergy.com/pdf/York%...ZE%20R-410.pdf Bottom of page 2,, line brazing, Do Not Soft solder!!
Professional Member
Craig1 -- You lost me, dude.
Regular Guest
Is that Sugarless gum?? HAHA
Professional Member
pressure is measured in PSI, Pounds per Square Inch. If you had two 1 inch square pieces of tubing and joined them together and charged them with 400 PSI there would be 400 pounds of force pushing them apart.
However, the inside of our liquid line is not 1 square inch, it is a small portion of that.
the inside diamer of 3/8 tubing is 1/4"
the area of that inner diameter is .049 square inches.
multiply that times 400 and you get 19.6 pounds of force pushing the joint apart.
Professional Member
Sugarless is recommended for 410a. It has a higher tensile strength. Thats why you can blow bigger bubbles if you chew gum long enough to get all the sugar out.
God Speed, Jim. We'll miss you - 2-26-23
I come up with .2956 sq in surface area, which would be a total of 117.8 pounds of force.
Professional Member
I don't guarantee my calculation is correct, but I do guarantee yours is not
Theres no way a 1/4" circle takes up more than 1/4 of the area inside a 1"x1" box
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