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  1. #1
    Join Date
    Oct 2012
    Location
    San Diego CA.
    Posts
    19

    Changeing out 40 ton condensers

    So i'm changeing out two 40 ton condenser and as always the customer did not want to pay to change the evap coils.
    Old unit r-22, new condeser 410. I've done this before on 5 ton and smaller units useing rx-11 to flush and a good triple vac with no problems. But I can't get a comfortable amount of the old oil out even with the flush. Anyone done this before that could give me some advise . I've only got a week to do this and the amount of oil left in the lineset and coil does not give me a warm fuzzy feeling.

  2. #2
    Join Date
    Oct 2012
    Location
    San Diego CA.
    Posts
    19
    $3000 dollars worth of rx-11 and there is still some oil left in the lineset and coil. I've been told your allowed 10% but I'm still a little worried.

  3. #3
    Join Date
    Aug 2012
    Location
    Palmyra, Missouri, United States
    Posts
    224
    dont wanna change the evap but u are willing to spend 3000 dollars to flush old lineset and coil.. hmmm

  4. #4
    Join Date
    Oct 2012
    Location
    San Diego CA.
    Posts
    19
    I'm not customer is. Not my first choice but they did'nt want to fork out the money. ( 2 new evap coils $ 118.000)

  5. #5
    Join Date
    Aug 2012
    Location
    Palmyra, Missouri, United States
    Posts
    224
    Holy crap that's a huggggggee bit!@

  6. #6
    Join Date
    Apr 2003
    Location
    Maple Grove, MN
    Posts
    1,271
    Was the old system a bad burn-out? If not, I don't see the need for that much RX-11, just plain nitrogen should be good enough (and about $2900.00 cheaper).

    The importance of not mixing oils has been much debated on this site. I believe the general consensus is that it is not nearly important as it was first believed. Having a little mineral or AB oil in the system really shouldn't hurt anything.

    Having said that, if you haven't done so yet, drilling a hole in the bottom of any suction line traps to drain out any oil that may be in them would probably be a good idea. Also isolate the evaporator from the rest of the piping, remove the txv's, and blow everything out separately.

    If the unit doesn't have suction line traps, and too much oil seems to be settling into the evap, I would add them. Also make sure your suction piping isn't too big. Usually R410 equipment needs smaller pipe sizes than R22 equipment. This is also to ensure proper oil return.

  7. #7
    Join Date
    Oct 2012
    Location
    San Diego CA.
    Posts
    19
    Pipe sizing is coreect according to Trane's install guide and all traps removed. I,ve even blown rag plugs thru lineset to remove oil. It just seems like there is more. Starting up first unit tomorrow. I have reclaim company on standby just incase anything looks weird. I hope that if we run it a bit and then suck it all out and recharge it 90% of the mineral oil should be out.

  8. #8
    Join Date
    Oct 2012
    Location
    San Diego CA.
    Posts
    19
    Both units would burn out at least 2 compressor every 2-3 years on either circuit. Also condeser coil were gone, close to sea with now coating

  9. #9
    Join Date
    Mar 2011
    Location
    North Carolina Piedmont Area
    Posts
    449
    Ok Jay tell him what to do.

  10. #10
    Join Date
    Apr 2003
    Location
    Maple Grove, MN
    Posts
    1,271
    Be sure to install big filter driers (liquid and suction) with pressure ports on both sides of them and plan to monitor and change them out as often as necessary until you are confident there is no more acid or junk in the system. I would be more worried about the acid and debris than I would about the separate oil types.

  11. #11
    Join Date
    Oct 2012
    Location
    San Diego CA.
    Posts
    19
    Got it. Already done and thanks for the advise. I don't smell any acid in the system right now but I've already got two more sets of filters for both units,( liquid and suction).
    I'll post how it goes tomorrow and pray nothing major happens.

  12. #12
    Join Date
    May 2002
    Location
    evansville indiana
    Posts
    943
    You could get an oil refractometer to measure the ratio of mineral to POE.

    I had a split system i started that was built to order and the water cooled condensing unit was filled with mineral instead of poe.
    yes ,I questioned it before startup and was ordered to start it .
    I had to do many oil changes but with that tool I was confident that in the end i was below 5% mineral oil .

    If you've spent that much on flush a couple hundred dollar tool shouldn't kill the job.
    mikeacman

  13. #13
    Join Date
    Feb 2009
    Location
    Tallahassee, FL
    Posts
    6,031
    Captn - you have a high concentration of residual flush now as well.

    If lineset is long you may need to cut in 50 - 75 ft length and flush from high spots to low always with gravity.

    Lots of nitrogen and cutting lineset at low points is the only way that makes sense IMO.

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