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  1. #1
    Join Date
    Jan 2004
    Posts
    6

    A/C solenoid valves

    Guys I just ran across a Bryant 2 ton unit that has an Alco 100RB direct-acting solenoid valve in the liquid line just short of the evaporator. Its leaking where the stem and the body meet. This the first unit I have come across with one of these valves in it. Can you tell me what it actually does and if it has to be in their. It's not the metering device like a TXV or a AXV so why does it have to be in their. Thanks

  2. #2
    Join Date
    Apr 2007
    Location
    Philadelphia
    Posts
    2,193
    Quote Originally Posted by duder49 View Post
    Guys I just ran across a Bryant 2 ton unit that has an Alco 100RB direct-acting solenoid valve in the liquid line just short of the evaporator. Its leaking where the stem and the body meet. This the first unit I have come across with one of these valves in it. Can you tell me what it actually does and if it has to be in their. It's not the metering device like a TXV or a AXV so why does it have to be in their. Thanks
    it is for pump down..when youre call for cooling is satisfied..it closes and the compressor pumps the refrigerant out if the evap and suctio line into the condenser.it should be controlled by the stat and their should be a low pressure switch to hold out your compressor..is this in a residence???

  3. #3
    Join Date
    Mar 2005
    Location
    burlington county n.j.
    Posts
    9,761
    doubt that is a pump down on a residential unit.

    carrier, bryant and some others used a solenoid to shut off the liquid line when the unit shut off. said to prevent flooded start up and to help efficiency by having a full column of liquid at start up.

    usually just wired to y to close when unit shuts down.

    as old as that unit is i would probably just remove it.

  4. #4
    Join Date
    Nov 2006
    Location
    SC
    Posts
    930
    I found one like that just a few weeks ago, except the valve was in the LL at the condenser unit. In my case, it IS the metering device. The valve has an orifice that remains open when the solenoid is off, and it replaces the piston type metering device that came with the thing. Check the unit in heat mode. If you can tell an obvious temperature difference from one side to the other of that valve, it's probably a metering device.

  5. #5
    Join Date
    Dec 2002
    Location
    Houston,Tx.
    Posts
    16,115
    I thought those Liquid Line Solenoids were installed when you had a long line set
    I also heard they are better for efficiency keeps the system from equalizing so it's
    better for start up but who knows I will go with the longer line set thing.
    __________________________________________________ _______________________
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  6. #6
    Join Date
    Apr 2007
    Location
    Philadelphia
    Posts
    2,193
    ok my mistake..sorry for the misinformation..thats why i asked if it was on a resi unit..i know it is rare if it was

  7. #7
    It is also used if the height of the line set is more than 20 ft., at least with Bryant. I think the length of the line set would have to be more than 80 ft. once again with Bryant. If the line set is more than 60 ft. you would have to up size the suction line.

  8. #8
    Join Date
    Dec 2006
    Location
    Middle Tennessee
    Posts
    11,347

    *

    years ago if the a/h was installed inside a bedroom closet, i have installed a few of those solenoids

    in order to stop the liquid line from (noisy gurgling) when condenser cycles off!



    .

  9. #9
    Join Date
    Jun 2007
    Location
    Round Rock
    Posts
    3,623
    Bryant/Carrier put them in with their units about 4-5 years ago for a while on their higher end stuff. It has to do with getting the oil to run back to the compressor after it shut down so the line wouldn't be full of oil and liquid or so I was told. It wouldn't clog the metering device and give it a hard time starting. It only lasted a year or less. It isn't a metering device nor has anything to do with having a long line set or an air handler lower than the unit or for pumpdown line a refrigeration unit. Bryant would have had no idea what the application was when you purchased the unit, they came inside the unit with the filter dryer. They quit putting them in almost as quickly as they put them in. I've removed a few of them when they started leaking with no problems thereafter. I put them in when they came inside the units cause my boss made me.

  10. #10
    Join Date
    Dec 2006
    Location
    Middle Tennessee
    Posts
    11,347

    *

    Quote Originally Posted by bmathews View Post
    Bryant/Carrier put them in with their units about 4-5 years ago for a while on their higher end stuff. It isn't a metering device nor has anything to do with having a long line set or an air handler lower than the unit or for pumpdown line a refrigeration unit. I've removed a few of them when they started leaking with no problems thereafter.

    i agree with that, although i think it was more like 10 years ago!

    also i do remember removing (bypassing with a peice of copper) a few of those faulty solenoids

    which were located at the condenser on those carriers!



    .

  11. #11
    Join Date
    Mar 2007
    Location
    NW AR
    Posts
    2,478
    Quote Originally Posted by Airmechanical View Post
    years ago if the a/h was installed inside a bedroom closet, i have installed a few of those solenoids

    in order to stop the liquid line from (noisy gurgling) when condenser cycles off!



    .
    Yep. Ive added a couple to systems that hammer on shutdown.

  12. #12
    Quote Originally Posted by Airmechanical View Post
    i agree with that, although i think it was more like 10 years ago!

    also i do remember removing (bypassing with a peice of copper) a few of those faulty solenoids

    which were located at the condenser on those carriers!



    .
    We have also installed a few of these, have you ever read the install instructions?

  13. #13
    Quote Originally Posted by Airmechanical View Post
    i agree with that, although i think it was more like 10 years ago!

    also i do remember removing (bypassing with a peice of copper) a few of those faulty solenoids

    which were located at the condenser on those carriers!



    .
    We have also installed a few of these, have you ever read the install instructions? The last one we installed was less than 2 months ago

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