Click here to Find a Contractor in your area.
Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit

Heat Pump

Why not? What would be wrong with installing a one way liquid line filter/drier instead of the typical biflow f/d used on H/P's ? This is assuming there is zero debris in the system!


  • JStar
    JStar Member Posts: 2,752

    I've had a helper install the FD backwards on a straight AC system. Never had a problem.
  • don_9
    don_9 Member Posts: 395
    edited October 2012

    Like Jstar we removed an ac system that was 25 years old and it had a drier going the wrong way, they never had a issue.

    Maybe we can get Eugene to put one on one of his system in the lab and see what kind of effect it has on that system.
  • alotlikeearl
    alotlikeearl Member Posts: 68

    Picked this up from somewhere:

    Most solid-core desiccants are molded into a cylindrical block with a tapered axial hole down the center to allow for the uniform flow of the refrigerant through the entire bed of desiccant. This is why filter-driers are directional with the direction of flow indicated on the container. Installing the filter-drier in the wrong direction causes non-uniform refrigerant to desiccant contact and increases pressure drop. Bi-flow filter-driers are available for heat pump applications

  • Techman
    Techman Member Posts: 2,144
    Filter Drier

    Hi Jerry.I know that the shell w/ the changeable core has the tapered opening in the core and is supposed to be flow direction sensitive , but I wasn't aware of the throw away's (solid core) being that way . I'll cut one open just out of courisioty and in the quest of knowledge.
  • alotlikeearl
    alotlikeearl Member Posts: 68
    Love To Learn

    Be sure and let us know what you find.

  • Techman
    Techman Member Posts: 2,144

    There is a small cone in the solid core f/d as Jerry said ,I did not know that, and according to Parker/Sporlan there is a ZERO effect to the freon flow by having a LL f/d installed "backwards" in the LL But also according to Sporlan "are you willing to gamble that there is no debris/foreign matter floating around the heatpump system".So I have my answer!
  • Direction of flow

    Just between us....

    For the most part, if the drier is in good shape, it will work fine in either direction. The problem seems to arise if the drier is installed backwards and the desiccant cracks.

    Remember, the filter drier does two things.... it filters and dries.

    The filter is to be downstream of the drier to capture any particulates that might "find their way in to the system". These "particulates" include any pieces of the desiccant that might break loose as a result of improper handling, installation, age, etc.

    Imagine what would happen if the desiccant broke up and the drier was installed backwards? You would have a liquid line full of desiccant chunks!

    No need for you to cut one open, as I have some already opened. I will post some pics when I get back from Dallas.

  • Techman
    Techman Member Posts: 2,144
    edited October 2012
    Trumped again!!!!!!!!

    Thats why YOU are THE PROFESSOR. So I'll revise my "So I have my answer" to now I have my answer!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!LOL lol LOL
  • Techman
    Techman Member Posts: 2,144
    How about

    putting two 163 F/D w/ the outlets of each facing towards each other so the inlet screens are recieving the in of the freon flow? Again assuming there is no debris floating around .
This discussion has been closed.


It looks like you're new here. If you want to get involved, click one of these buttons!