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  1. #1
    Join Date
    Feb 2009
    Location
    Manchester, TN
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    Debate on filter driers.

    I've recently started with a new company and I'm trying to adapt to their ways of doing things. Today I had a short debate about filter driers. Unit I was on is a split system r22 Trane and had a bad indoor txv and a leak in the evap coil. I really see no need in evacuating the entire system just to install a new filter in the condensing unit. I would prefer to do a partial pump down then recover the remaining Freon. If I use good clean practices while changing out the coil and txv why should I need to change out the drier in the condenser? I have no reason to believe it is at all dirty. I proposed if he was worried about it I could always install another new line drier in the liquid line on the lineset outside of the condenser. Boss was not enthusiastic about having more than 1 drier in the system at all. I honestly can't think of a reason 1 extra drier will hurt anything at all. In most cases I am all for a new drier. But in this case I see no need to remove 10 lbs of r22 just for the drier.

  2. #2
    Join Date
    Jan 2005
    Posts
    42
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    On a txv changeout I probably wouldn't change it. Just depends on what the cause of the txv failure was. But on an evaporator and txv replacement I would have pulled that old one out.

  3. #3
    Join Date
    Aug 2002
    Location
    manitowoc wisconsin
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    4,947
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    Anytime a system is open the drier should be replaced.Arguing otherwise with the guy that signs your check is not very smart.imo
    Take your time & do it right!

  4. #4
    Join Date
    May 2000
    Location
    Houston, TX, USA
    Posts
    376
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    X2 anytime system is open it should be changed. Realistically it is not always done. If I have a condensing unit with a drier inside the unit, I would relocate the drier outside the unit so it can be changed next time with a pump down. It's always good insurance to replace drier.

  5. #5
    Join Date
    Oct 2004
    Location
    Yakima, WA
    Posts
    1,845
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    For a quick txv changeout I won't change the drier. For a leak in the evap coil... was the system flat, did it ever pull into a vacuum?

    We sometimes put a second drier on a system. Lennox heat pumps come with a drier brazed onto the end of the outdoor txv. Rather than put extra stress on the valve we usually don't bother it except for major surgery (compressor, rev valve, or obviously outdoor txv). When it does come out, though, it is relocated outside of the condenser.

  6. #6
    Join Date
    Jan 2004
    Location
    PA
    Posts
    78,318
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    For a screw on TXV change out, or a powerhead change out, I don't change the FD.

    If your boss wants it done, and is willing to pay you to do it. Do it.
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  7. #7
    Join Date
    Mar 2014
    Location
    North DFW, TX
    Posts
    37
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    Seems to me to be a bit of a gray area. If I'm brazing the expansion valve in, I'm changing the drier for sure. But, I can see what you're saying - if you work super clean, nitrogen fill that area at the new TXV, I can't foresee any issues. However, the older I get - the more I prefer to err on the side of caution and thoroughness.

    Some outfits just want to be able to charge for the new drier, no doubt.

  8. #8
    Join Date
    Aug 2007
    Location
    Winter Haven, FL
    Posts
    4,383
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    The purpose of the drier is to collect and hold moisture. If the system is open to the atmosphere, then a new drier needs to be installed. It is impossible to remove all of the moisture from a system by vacuum, so a drier is used. I always change the drier if the system is opened. If you are getting paid to do a job...do it right.

  9. #9
    Join Date
    Nov 2006
    Location
    Southeastern Pa
    Posts
    32,048
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    If the system is opened by me, the dryer will be replaced.
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  10. #10
    Join Date
    Feb 2009
    Location
    Manchester, TN
    Posts
    399
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    Thread Starter
    A little backstory as to why I am even considering this. Unit was very low on Freon. Checked indoor coil and besides easily detecting a leak everything looked fine. HO did not want to change out the coil. I didn't want to charge it up but that is what HO wanted. I even called the lead tech(my boss) to ensure I could do it. During charging it up I hit subcooled on liquid line to early and still had a very high superheat. At this point stopped and diagnosed leaking coil and a bad txv. Lead tech does not want to eat 4 lbs of r22 so his recommendation is to recover to a new tank so the drier can be changed out then reuse the recovered r22. We aren't arguing about it at all. We are discussing options. I trust I can keep a system clean during a repair a lot more than a recovery tank. We have a job scheduled tomorrow where I'll probably try to convince again to just eat the freon as main choice. Second would be do it without the drier. I'm still strongly against reusing recovered freon. I just don't trust it and would prefer to skip the drier change over doing it. Thanks for replies. It may end up being mute anyways as sales guy is going to give a change out quote tomorrow morning.

  11. #11
    Join Date
    Jun 2006
    Location
    Southeastern Connecticut
    Posts
    868
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    I will go against the grain here and agree with your line of thinking. I do not like to reuse refrigerant even with new tanks. Unless I am going to use a brand new recovery unit also, which isn't practical. I know mine has seen a lot of burnouts and other trash and would not want to contaminate the clean refrigerant coming out.

    I think the filter drier installed in the condensing unit is a ridiculous practice and should be stopped. Send it loose with the condensing unit and let us sweat it in.
    Bottom line do whatever your Boss decides he wants you to do.

  12. #12
    Join Date
    Feb 2013
    Location
    Nashville, TN
    Posts
    20
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    the best thing to do is anytime system is open change to filter drier. Although I am guilty of leaving them sometimes... especially when their inside the condenser... and really i've never had a call back from it, but I still know its best to always change it

  13. #13
    Join Date
    Jul 2012
    Location
    Central TX
    Posts
    679
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    I don't trust recovery tanks at all. I have used fresh recovery tanks to recover good gas and seen black crap come out of the tank. If I have to recover, the unit gets virgin refrigerant. I like to change the drier anytime a system is opened up just to play it safe. With that said it shouldn't need it if it is a TXV replacement and the failure is not due to trash in the system. A good nitrogen purge and a vacuum would be just fine. dngtig is right, manufacturers installing driers in the condenser needs to stop.

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