Filter drier question - Page 3
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  1. #27
    Join Date
    Jul 2009
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    South Carolina
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    Are we all talking about the same scenario.
    The OP is changing out an evaporator coil which I assume is because of a refrigerant leak. Nothing was suggested that there was any problems with system running properly so there is no reason to suspect any internal problems with the system at this time. You wouldn't suggest changing the dryer inside the condenser if you had a bad capacitor while you were on the job if it didn't show any problematic symptoms. So why would you expect any problems with it just because you're working outside the condenser? I could see if you want to change the factory 5cu. in dryer & put a 16cu. in. instead for more protection against moisture but to do it because the existing dryer might be bad doesn't make sense to me.
    Gary
    -----------
    http://www.oceanhvac.com
    An engineer designs what he would never work on.
    A technician works on what he would never design.

  2. #28
    Join Date
    Aug 2012
    Location
    Palmyra, Missouri, United States
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    224
    Opening up a system is all you need to do in order to justify changing the drier

  3. #29
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    Apr 2004
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    Des Plaines,IL
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    Quote Originally Posted by garyed View Post
    I disagree,
    If you can pump down the system then you have less chance of contamination entering the system if you leave the internal dryer alone.
    If you think the factory installed dryer is contaminated then you shouldn't reuse the refrigerant either. Changing the dryer is adding another two or four sweat joints too.
    Every time you open the system, you introduce moisture into the system. Granted if you evacuate below 500 microns, you will get most of the mositure out, but not all of it. That is the purpose of the filter/dryer to collect any remaining mositure. So say you install a new system and evacuate properly and get the system running. There will be some moisture in the factory drier. The system runs OK. Now later on a leak develops in the evaporator coil and you need to replace it. You open the system again and expose it to moisture again, evacuate it and a little more moisture is collected in the factory filter/dryer. You really don't know how much moisture the filter/dryer will hold and it becomes a problem until you have restriction issues. Worse yet, you may not have an issue after you evacuate and recharge. It may show up later.
    Stuart
    Lack of airflow destroys compressors.

  4. #30
    Join Date
    Aug 2012
    Location
    Palmyra, Missouri, United States
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    224
    Quit being lazy! install new driers! takes 15 minutes

  5. #31
    Join Date
    Jul 2009
    Location
    South Carolina
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    Quote Originally Posted by mcewans View Post
    Every time you open the system, you introduce moisture into the system. Granted if you evacuate below 500 microns, you will get most of the mositure out, but not all of it. That is the purpose of the filter/dryer to collect any remaining mositure. So say you install a new system and evacuate properly and get the system running. There will be some moisture in the factory drier. The system runs OK. Now later on a leak develops in the evaporator coil and you need to replace it. You open the system again and expose it to moisture again, evacuate it and a little more moisture is collected in the factory filter/dryer. You really don't know how much moisture the filter/dryer will hold and it becomes a problem until you have restriction issues. Worse yet, you may not have an issue after you evacuate and recharge. It may show up later.
    Lets take a brand new system on new construction with new line sets.
    The condenser has a factory installed dryer in it.
    Your lines are exposed to air & moisture until they are sealed & vacuumed. Do you put a dryer in?
    The manufacturers do not recommend installing an external dryer when they have already put one inside the condenser on a new install. If you pump the system down I don't see the difference. Sure there's always the possibility of a bad install where there's already contamination in the system. If you think that then go ahead & replace the old dryer but be sure to add virgin refrigerant too or else you did a lot of work for nothing.
    Gary
    -----------
    http://www.oceanhvac.com
    An engineer designs what he would never work on.
    A technician works on what he would never design.

  6. #32
    Join Date
    Aug 2012
    Location
    Palmyra, Missouri, United States
    Posts
    224

    Cool

    Quote Originally Posted by garyed View Post
    Lets take a brand new system on new construction with new line sets.
    The condenser has a factory installed dryer in it.
    Your lines are exposed to air & moisture until they are sealed & vacuumed. Do you put a dryer in?
    The manufacturers do not recommend installing an external dryer when they have already put one inside the condenser on a new install. If you pump the system down I don't see the difference. Sure there's always the possibility of a bad install where there's already contamination in the system. If you think that then go ahead & replace the old dryer but be sure to add virgin refrigerant too or else you did a lot of work for nothing.
    Of course if its a brand new unit with a factory installed liquid line filter drier in it then no u wouldnt need to install a second drier (NEVER 2 DRIERS).. but next summer when you replace a leaking evaporator coil that drier (in the condensing unit) needs cut out and piping repaired and new liquid line drier needs installed at inlet of evaporator coil.

  7. #33
    Join Date
    Nov 2011
    Location
    Michigan
    Posts
    53
    IF your not going to take the old one out why add another one? the reasone for changing or adding a filter drier is so you are starting fresh, no?

  8. #34
    Join Date
    Aug 2001
    Location
    Pavilion, NY
    Posts
    2,094
    How many times do you guys see a plugged/restricted drier? Honesty I Have never come across a ll drier plugged. It makes me wonder how many times I have missed it.
    ...

  9. #35
    Join Date
    Jul 2009
    Location
    Kansas
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    368
    Quote Originally Posted by kangaroogod View Post
    How many times do you guys see a plugged/restricted drier? Honesty I Have never come across a ll drier plugged. It makes me wonder how many times I have missed it.
    Found one recently where you could feel the temp drop across it.

  10. #36
    Join Date
    Feb 2009
    Location
    Tallahassee, FL
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    5,973
    More than you know.

  11. #37
    Join Date
    Feb 2006
    Location
    USA
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    4,381
    Quote Originally Posted by kangaroogod View Post
    How many times do you guys see a plugged/restricted drier? Honesty I Have never come across a ll drier plugged. It makes me wonder how many times I have missed it.
    On fractional horse stuff with copper spun driers . . A lot ... Trane rtus . . Often enough to know that i check that first before thinking it's the orifices in the header .....

    Sent from my HTC Sensation 4G using Tapatalk 2

  12. #38
    Join Date
    Jan 2004
    Location
    Lancaster PA
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    67,584
    Quote Originally Posted by carmon View Post
    I have not and will not install the drier inside.... I see no point..... i like it outside so I dont have to braze in the customers home if repairs are required..... why do manufactures install them in the condensing unit now..... who is teaching this install the drier by the coil..... i dissagree
    To make sure one is installed. Some contractors would keep the FD and resell it on a call somewhere else instead of installing it on the new system if they sent it loose.


    Quote Originally Posted by garyed View Post
    It sounds like there are two different arguments here.
    1 - If there is already a factory installed dryer in the condenser does it need to be changed or added to if you can pump the system down.

    Just because you can pump the system down doesn't mean the FD isn't restricting. And when its in the cabinet, you can't tell if its beginning to restrict.

    2- Does it really matter if the dryer is closer to the indoor coil or condenser.

    If the air handler/evap coil is in an attic where it will get hotter then if it was outside, its better to install it outside. if its in a basement then its better to install it at the evap.

    I say no to both questions with these assumptions.
    1 - There is no reason to suspect the dryer is contaminated or plugged.
    If you suspect it is contaminated then virgin refrigerant should be used any ways. In that case cut out the original dryer & install one outside the condenser.
    2 - There is no reason to suspect any trash might be in the liquid line before closing up the system. A good nitrogen purge should put your mind at rest.
    On the OP's system, if its been leaking, then you don't know if it ever went into a vacuum while running with a frozen coil, and drew some moisture in. A new LLFD is a small piece of insurance that you have done due diligence in trying to keep the system running as long as possible.
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  13. #39
    Join Date
    Jul 2006
    Location
    Virginia
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    4,600
    Replaceing a filter drier inside a unit that there is nothing wrong with is adding a expense that is not needed. On a evap coil replacement i pump the system down to about 25 close it off recover the rest .

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