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  1. #14
    Join Date
    Dec 2002
    Location
    Houston,Tx.
    Posts
    15,912
    I have never heard of a single phase scroll running backwards but I have heard of 3-ph.scroll running backwards, but hey I am still learning.
    __________________________________________________ _______________________
    “Experience is a hard teacher because she gives the test first, the lesson afterwards". - Vernon Law

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  2. #15
    Join Date
    Jun 2005
    Location
    New York
    Posts
    207
    Thanks Mrbill, I was kidding about the 50hz comment. I tried calling my guy just now, but I guess its Miller time lol. I think everything should have a time delay IMO, even 3ph. My Rheems and Ruuds, that I install or service(12 seer) dont even come w/ time delays, most delays I see on resi are from the stat. On carrier, like the little 3 toners from today had clo's, I believe correct me if I am wrong, dont act as a short cycle timer. Its for high/ low short cycling(makes them manual reset) and will break the control to the contactor if it doesnt see amp draw from the compressor, those things I know the clo does on the carriers for the crappy cassets I started up today, but did not notice a time delay, I kinda short cycled the compressors playing w/ the control wiring to them.. I am on Long Island ( New York). Again, Thanks Mrbill.

  3. #16
    Join Date
    Jan 2004
    Location
    Midlothian, Virginia
    Posts
    195

    sporlan web sight

    wow reading is a dangerous thing.

    i went to sporlan's web sight and down loaded info on txvs.

    it seem to select one you need to know the temp of the liquid at valve (generally abou 100 f) and pressure drop across the txv. with these values you find two numbers or correction factors to multiply the valves tonnage by. the tonnage is foung in a table for each valve at the evaporators design opperating temp in ac case about 40.

    you are shooting fo the odu tonnage or a bit above after you multiply the factors times the tonnage at 40 from the table. wow

    with this done you can now select the charge of bulb. sporlan has about 4 that can be used for r22.

    now you choose the valve body type you need, there are about 8 if i remember correctly. (sweat, flare, and many shapes and sizes)


    now for another question

    in a heat pump application do i need to purchase a seprate check valve that is sweated into this set up to allow for flow around the valve in heat mode? little is mentioned about this in the literature i down loaded.
    Goodbyee stranger it's been nice. Hope you find your paradise! Hey it aint rocket science, "It's a Trade !"

  4. #17
    Join Date
    Aug 2003
    Location
    Fort Worth, TX
    Posts
    11,316
    now for another question

    in a heat pump application do i need to purchase a seprate check valve that is sweated into this set up to allow for flow around the valve in heat mode? little is mentioned about this in the literature i down loaded.
    Sporlan makes a TXV with a built-in check valve. Funny thing is, you won't see it in Sporlan's catalog or valve selection literature. But flip open your United Refrigeration catalog to the TXV section and that valve is practically on the first page in that section.

    VGA is a very common thermostatic bulb charge on hi-temp (a/c) for R22 on Sporlan TXV's.
    • Electricity makes refrigeration happen.
    • Refrigeration makes the HVAC psychrometric process happen.
    • HVAC pyschrometrics is what makes indoor human comfort happen...IF the ducts AND the building envelope cooperate.


    A building is NOT beautiful unless it is also comfortable.

  5. #18
    Join Date
    Jan 2004
    Location
    Midlothian, Virginia
    Posts
    195
    yes shophound. VGA seems to be their reccomended thermostatic bulb charge for R22 on Sporlan TXV's. Its pressure limiting chateristics and anti hunt abilities are mentioned in bulletin 10-9.

    another question should the valve body be mounted outside of the ahu to keep it's temp above that of the bulb. (if the valve body temp is lower than bulb charge migration to body occurs when a vapor charge is used. when this happens the valve doesnt work. )

    if you remove the piston inside of ahu that is positioned just before the distributor and mount the txv outside does the approximatly 10 inches or liquid line between the txv and the distributor interfere with the distributors job of equally feeding the evap coil.

    i guess im asking should a distributor always immediatly follow the txv to make the equal distribution work?


    it this is the case, then the valve body on a txv with vapor charge must go inside of the ahu where it can become colder than the charge in bulb which will cause it to stop working.

    one more question is vga charged bulb a vapor r22 charged bulb or cross charged liquid or cross charged vapor

    damn txvs are close to rocket science!
    Goodbyee stranger it's been nice. Hope you find your paradise! Hey it aint rocket science, "It's a Trade !"

  6. #19
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,875
    UPG part numbers for their txv's.

    2 to 2.5 ton----025-31988-000

    3 to 3.5 ton----025-31989-000

    4 to 5 ton------025-31990-000
    Contractor locator map

    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

  7. #20
    Join Date
    Aug 2004
    Location
    North Richland Hills, Texas
    Posts
    14,914
    Regarding units with scroll compressors coming with hard start kits from the factory.
    I think you will find that it is heat pumps that generally come with factory installed hard start kits, but straight cooling units will generally come with no start kit from the factory.

    Trane requires that you install a hard start kit on thier scroll compressors if you are going to operate a straight cooling system below certain outdoor ambient temperatures.
    Heat pumps normally operate below those temperatures, so many units come with the start kit already installed.
    If more government is the answer, then it's a really stupid question.

  8. #21
    Join Date
    Jan 2004
    Location
    Midlothian, Virginia
    Posts
    195
    well i found the answer to this one by further reading of sporland literature.

    one more question is vga charged bulb a vapor r22 charged bulb or cross charged liquid or cross charged vapor

    its a cross charged vapor.

    so the charge migration is a possibility.
    Goodbyee stranger it's been nice. Hope you find your paradise! Hey it aint rocket science, "It's a Trade !"

  9. #22
    Join Date
    Jan 2004
    Location
    Midlothian, Virginia
    Posts
    195
    any answers for these questions guys?

    question should the valve body be mounted outside of the ahu to keep it's temp above that of the bulb. (if the valve body temp is lower than bulb charge migration to body occurs when a vapor charge is used. when this happens the valve doesnt work. )

    if you remove the piston inside of ahu that is positioned just before the distributor and mount the txv outside does the approximatly 10 inches or liquid line between the txv and the distributor interfere with the distributors job of equally feeding the evap coil.

    i guess im asking should a distributor always immediatly follow the txv to make the equal distribution work?


    if this is the case, then the valve body on a txv with vapor charge must go inside of the ahu where it can become colder than the charge in bulb which will cause it to stop working.
    Goodbyee stranger it's been nice. Hope you find your paradise! Hey it aint rocket science, "It's a Trade !"

  10. #23
    Join Date
    Jun 2005
    Location
    New York
    Posts
    207
    Hello Mr.Bill, I almost forgot about this. I spoke w/ the Rheem (Ruud) tech people, and your kinda correct lol. They install the hard start on both 3 1/2 ton and up 12 and 14 seer. The reason they said is that they just want to on those sized machines due to the extra juice the system holds. I said what if I have a 3 ton w/ a very long line set, they said it wouldnt hurt to put one in, I said, do you feel its needed? They said no,,,, hummmmmm. I dont understand them lol. One of my buddies knows someone for Copland and said it isnt needed on 1PH scrolls. I agree. But anyway, it wasnt just your 5 ton 14 that has them. Have a great weekend and happy 4 th.

  11. #24
    Join Date
    Jan 2004
    Location
    New Jersey
    Posts
    534

    sizing txv and need for hard start kit

    1992 I installed 2.5 ton 12 SEER Ruud/copeland Scroll/TEV,in my own home. Experienced failure to restart, called Copeland and Ruud, Ruud sent me the hard start gear,end of story.
    The last few years when the compressor cycles off, it sounds like the unit is full of marbles (ratting noise) I won't change it out until it quits cooling.

  12. #25
    Join Date
    Jun 2005
    Location
    New York
    Posts
    207

    Re: sizing txv and need for hard start kit

    Originally posted by fastfred
    1992 I installed 2.5 ton 12 SEER Ruud/copeland Scroll/TEV,in my own home. Experienced failure to restart, called Copeland and Ruud, Ruud sent me the hard start gear,end of story.
    The last few years when the compressor cycles off, it sounds like the unit is full of marbles (ratting noise) I won't change it out until it quits cooling.
    Sounds like you have liquid migrating, laying in the compressor, thats what they sound like when liqiud lays in there and then she starts. Your discharge check must not be holding if it hardstarts. I would check your charge and piping, install a belly type heater around that thing to help w/ the liquid, or you will loose it.

  13. #26
    Join Date
    Jan 2004
    Location
    New Jersey
    Posts
    534

    sizing txv and need for hard start kit

    Ultratec:
    Thanks for the response. Regarding the noise, as I stated the noise occurs at the end of a call for cooling(cycles off) and as the compressor is coming to a stop. Sort of sounds like loose connecting rods in a recip. Start is normal.
    Back in the day when first released the info stated ,
    1-no start assist needed.
    2-no crankcase heater needed.
    3-literature stated the compressor could handle a screw being
    pumped thru it.
    4-compressor was better able to handle liquid.
    All good selling points. But as seen here in other post's the
    mfgrs have installed and continue to install assist kits.

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