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  1. #14
    Join Date
    Oct 2012
    Location
    Sacramento,ca
    Posts
    196
    Quote Originally Posted by hvacrmedic View Post
    The subject here is suction line filter driers. Suction line driers will typically have pressure taps on them. LL driers typically won't.

    As for your initial comment, there won't be a temperature drop across either a suction line drier or liquid line drier unless there is at least some liquid going into it, and a liquid/vapor mixture going out of it. If you have either gas-in-and-gas-out or liquid-in-and-liquid-out, then you get no temperature drop. In either of these two cases you'd typically need some means of measuring the pressure drop directly. Adding a pressure tap is the only practical way to do that in some cases, so don't hesitate to do that when you suspect a restriction and aren't seeing a temperature drop.

    You can have a significant restriction with no temperature drop across it so don't assume that there's no restriction just because there's no temperature drop. IOW, what you've always been told is wrong at face value. There's a lot more to be said, but you can search the forum for threads that cover this topic.
    Thanks for the insight this is why i come here to have clarity on the wrong things i have be taught. I must be buying some cheap suction filters because none of the ones at my local vendor have taps on them, i carry piercing valves for this though.

  2. #15
    Join Date
    Jul 2005
    Posts
    5,576
    Quote Originally Posted by Barrettservices View Post
    Thanks for the insight this is why i come here to have clarity on the wrong things i have be taught. I must be buying some cheap suction filters because none of the ones at my local vendor have taps on them, i carry piercing valves for this though.
    You should think about buying them elsewhere.

  3. #16
    Join Date
    Aug 2012
    Posts
    2,682
    What about over sizing the slfd, would that elliminate the need to change it out???
    My name is TooCoolforschool and I am a chronic over charger.

  4. #17
    Join Date
    Apr 2003
    Location
    Maryville, Tennessee
    Posts
    420
    We almost never install a suction line dryer but, we always replace/install a LLFD. We have had good results. I'm not arguing in favor of this policy. I'm just say'n that's what we do and, we have a good track record doing it.
    -Marty

  5. #18
    Join Date
    Sep 2002
    Location
    Virginia
    Posts
    3,231
    I try to treat customers units as if my very own , and if I had a burn out , I would want a big ol high acid suction filter there catching anything coming out of the indoor coil that might harm the new compressor.

  6. #19
    Join Date
    Jul 2009
    Location
    Columbia, MD
    Posts
    4,252
    I would install my suction line drier outside of the unit and wire it to stay in cooling. This way i didn't have to do handstands on trane units.

  7. #20
    Join Date
    Mar 2010
    Location
    Kent, WA.
    Posts
    189
    i wish more people on the commercial end would come back and remove the suction filter/dryer. i have a few accounts that i inherited and they have some that were installed in the 80's and 90's, units check out fine tho so im not removing till another failure.
    Experience
    Is what you get when you didn't get what you wanted.

    A positive attidude will not solve all your problems, but it will annoy enough people to make it worthwhile.

  8. #21
    Join Date
    Jan 2008
    Location
    michigan
    Posts
    1,145
    Quote Originally Posted by hotrodrob View Post
    i wish more people on the commercial end would come back and remove the suction filter/dryer. i have a few accounts that i inherited and they have some that were installed in the 80's and 90's, units check out fine tho so im not removing till another failure.
    They may have felts in them, whats the harm?

  9. #22
    Join Date
    Apr 2003
    Location
    Maryville, Tennessee
    Posts
    420
    I did that on a Trane HP that had had several compressor failures and no suction dryers were installed. Have not been back since.
    -Marty

  10. #23
    Join Date
    Apr 2003
    Location
    Maryville, Tennessee
    Posts
    420
    Agreed but most customers in our market would not pay for the cost involved. Your market may be different?
    -Marty

  11. #24
    Join Date
    Sep 2002
    Location
    Virginia
    Posts
    3,231
    Quote Originally Posted by m singer View Post
    Agreed but most customers in our market would not pay for the cost involved. Your market may be different?
    you know what , all you can do is offer them good advice , after that , the balls in their court , and thats about all you can do buddy

    Everyone here sees it all of the time .... most of the time we walk away shaking our heads

    Oh well , i think some smart fella once named it "job security"

  12. #25
    Join Date
    Jun 2007
    Location
    Greenwood Indiana (Indianapolis)
    Posts
    420
    acid away works. There is different types depending on what refrigerant you have. I am a big believer in suction line dryers. I also am a big believer that they can stay in if the pressure difference is minimal.
    As iron sharpens iron so one man sharpens another Proverbs 27:17 NIV84

  13. #26
    Join Date
    Feb 2012
    Location
    Moscow
    Posts
    16
    But if the pressure drop is up to 30 psig due to long piping I'd rather put largher compressor in first after replacing the burning out compressor.

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