Moving from R22 to R410--Flush Lines?

[Tenderpaw]

I'm having a whole system change out and my old system is R22 and the new one is R410. They are reusing the refridgerant lines as they are built into the wall of the house and i'm getting conflicting stories on the need to flush. One contractor made a big deal about their 3 step flushing process. Another said he only runs nitrogen through the lines and doesn't put flush in the system because he thinks only freon should go in there. Still another said he runs nitrogen and adds an extra filter drier before the evap to catch anything that might break loose later. Who should i believe?

Thanks,

Dave

 

[Stuff]

First verify that the lines are the correct size for the new system. Flushing is to get the crud and oil out. Nitrogen by itself won't clear everything especially if there are low spots.

 

[Sponsor]

 

[WorthFlorida]

How old are the lines? Texas homes, like Florida are all on concrete slabs. If the air handler is in the middle of the home usually the new lines are run up the outside wall to the attic space and a chase is placed over them. You'll probably see them everywhere. I had a home where the both the 1st floor and 2nd floor AC units both had leaked over time and I had to run new lines into the attic space.

In my opinion if the lines are over 20 years old have them replaced regardless. As for the type of flush just leave it to the tech or company you're using.

The opinions and what gets done are generally determined by the experience of the technician. I took a basic AC course 10 years ago and the instructor recommended nitrogen. My co worker, a certified AC tech with an EPA certificate felt the vacuum test and procedure before charging the system was enough. This year I got two bids for my son's house for a new AC unit and the lines that were installed in 1977 and it was R22 system. One stated that leaving the lines was OK, the second bid had the line replacement in the bid. Didn't want to chance it that a leak could occur. I went with the new lines and it was $600 less than the first bid. FYI, all techs now install a filter/dryer on all new R410 systems. They cost is very low at wholesale and it may prevent a warranty service call. Here is a site that boost how good there filter dryer is but it has some information on how they work. http://www.achrnews.com/articles/94017-filter-driers-the-first-line-of-system-protection.