Something Pros Should Think About - HVAC - DIY Chatroom Home Improvement Forum


Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > HVAC

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Display Modes
Old 04-13-2009, 03:21 PM   #1
Member
 
hvaclover's Avatar
 
Join Date: Oct 2008
Location: Suburbs of Detroit Mi
Posts: 3,704
Rewards Points: 2,000
Default

Something Pros Should Think about


The rules may be changing on mixing POE and mineral oils together. The original reason for removing the mineral oil from the system had little to do with the mineral oil itself, and more to do with the paraffin waxes that used to be used in the motor windings of (semi)hermetic compressors. The mineral oil would dissolve the wax and circulate it in the system, and unless the mineral oil was removed from the system the waxes were still there. The HFC refrigerants couldn't dissolve much paraffin wax, and it dropped out in the first cold spot in the system (expansion device) and could plug up the system. The good news is that the waxes have been eliminated from the motor windings since the mid 1990s, so the original reason for removing the mineral oil is gone.

The other good news is that a typical line set doesn't hold much oil, so even if there were waxes used in the motor windings, there won't be enough remaining in the line set to cause problems. Blowing out any excess oil with nitrogen makes any potential problems even smaller. I really doubt you will find any problems from residual mineral oil in a system that reused the line set, whether it was flushed or not, or just blown out with nitrogen.

We have been doing a lot of work looking at what happens with oil circulation in systems when mixing mineral oil and POE together while using HFC refrigerants, and have given a series of technical papers at ASHRAE meetings. As little as 15% of POE added to mineral oil allows the mineral oil to mix into liquid HFC refrigerants. Our work was the basis for the recommendation to add some POE to R-422 systems if the oil circulation was not good enough. We are still doing more work in this area, and are learning even more about what the true limits of residual mineral oil needs to be to make a system running on HFC refrigerants have good oil circulation.

Eventually this new information will filter through the system and be picked up by the compressor and equipment manufacturers, and then make it into the service training programs. Until then, you may well hear people recommend that all the mineral oil should be removed when converting from mineral oil to POE. There is nothing wrong with this, it just may not be necessary any longer.

Rob Yost

Advertisement

__________________
Just slow, not stupid.
hvaclover is offline   Reply With Quote
Old 04-13-2009, 03:31 PM   #2
Hvac Pro
 
Join Date: Nov 2008
Location: Winnipeg, Canada
Posts: 10,122
Rewards Points: 882
Default

Something Pros Should Think about


I always like new lines or a proper flush. The old oil could be contaminated with acids from Bubba selling some new "reconditioned slightly used" R22 as a topping up stopgap getcha by till the compressor dies call. When you pay a lot of $$ for a new system I would want everything new. Reusing old 5/8" suction lines when the new condensor calls for 3/4" I dislike as well.

Advertisement

yuri is offline   Reply With Quote
Old 04-13-2009, 03:36 PM   #3
Member
 
hvaclover's Avatar
 
Join Date: Oct 2008
Location: Suburbs of Detroit Mi
Posts: 3,704
Rewards Points: 2,000
Default

Something Pros Should Think about


I don't have any prob using an old line set .But i give the HO a choice.
If the old line set has a lot of carbon and acid I flush R22 and recover. Use an over size filter drier.
__________________
Just slow, not stupid.
hvaclover is offline   Reply With Quote
Old 04-13-2009, 04:45 PM   #4
Member
 
Home Air Direct's Avatar
 
Join Date: Jan 2009
Location: Southern Illinois
Posts: 297
Rewards Points: 250
Default

Something Pros Should Think about


Quote:
Originally Posted by yuri View Post
The old oil could be contaminated with acids from Bubba selling some new "reconditioned slightly used" R22
You got a Bubba in Canada too? I thought they all lived here.
__________________
Settle down! If you were that important, the city would give you lights and a siren for your car
Home Air Direct is offline   Reply With Quote
Old 04-13-2009, 05:00 PM   #5
Hvac Pro
 
Join Date: Nov 2008
Location: Winnipeg, Canada
Posts: 10,122
Rewards Points: 882
Default

Something Pros Should Think about


Bubbas, Rednecks but no snakes. I hate snakes.
yuri is offline   Reply With Quote
Old 04-13-2009, 06:52 PM   #6
An old Tradesmen
 
Join Date: Oct 2008
Location: PA
Posts: 26,548
Rewards Points: 4,734
Default

Something Pros Should Think about


Converting to R410A has allowed less then 4% MO to POE for sometime now.

National Refrigerants has been working to prove to both compressor and equipment manufacturers for a few years now.
beenthere is offline   Reply With Quote
Old 04-14-2009, 09:06 AM   #7
Member
 
Join Date: Sep 2008
Location: Upstate New York
Posts: 368
Rewards Points: 250
Default

Something Pros Should Think about


Thanks for researching and pushing this issue. Creating a simpler and more cost-effective upgrade path for HOs is a win-win for all.
dac122 is offline   Reply With Quote
Old 04-14-2009, 09:48 AM   #8
Member
 
hvaclover's Avatar
 
Join Date: Oct 2008
Location: Suburbs of Detroit Mi
Posts: 3,704
Rewards Points: 2,000
Default

Something Pros Should Think about


I can't take credit for it. I remember reading the article and forgot where.

Another poster else where dug it up.

I just wanted to disseminate the info.
__________________
Just slow, not stupid.
hvaclover is offline   Reply With Quote
Old 04-14-2009, 12:02 PM   #9
An old Tradesmen
 
Join Date: Oct 2008
Location: PA
Posts: 26,548
Rewards Points: 4,734
Default

Something Pros Should Think about


Keep in mind.

that until the manfacturer, of the equipment being installed approves it.

They can still void your warranty, it their install instructions stay no mix allowed.

Advertisement

beenthere is offline   Reply With Quote
Reply


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Hey Pros: Did my YJ gauge manometer fail me? hvaclover HVAC 20 04-11-2009 07:22 PM
Ruud Service Manual, Pros don't want me to understand my system Ruuduser HVAC 56 03-29-2009 07:45 PM
purple martin/bat house pros and cons? DangerMouse Pest Control 12 01-15-2009 08:25 AM
Questions for the Pros Concordseeker Flooring 7 12-11-2007 06:13 PM
Please explain the pros and cons to gutters. curls00 Roofing/Siding 1 11-14-2007 01:42 PM




Top of Page | View New Posts