Page 2 of 7 FirstFirst 1234567 LastLast
Results 14 to 26 of 80
  1. #14
    Join Date
    Aug 2003
    Posts
    466
    I would think that the first thing to consider would be the amp draw of the 4 ton compressor. Once you install the compressor along with an appropriate sized capacitor, are the existing wiring and controls going to be able to support it?

    Is the breaker large enough to handle the amp load? Is the wiring large enough? Is the contactor large enough?

    Even if all of the electrical is upgraded to support the larger compressor, is there any way that the coils are going to be able to handle the capacity of refrigerant being pushed into them by that compressor? A metering device can only do so much and I am picturing that little Dutch boy holding back the massive amount of water behind the dyke with his finger.

    Is the indoor coil downstream from the electric heaters? Are the electric heaters allowed to operate at the same time as the heat pump does?

    All in all I would have to agree with your dad.

  2. #15
    Join Date
    Aug 2002
    Location
    Southold.calm
    Posts
    5,677
    Quote Originally Posted by yelram View Post
    And why is that? Or are your posts ALL completely useless? Tell me how many times you've witnessed a mis-sized compressor?
    That’s working. Can’t think on any off hand.

    My dads been doing this 30 years, and his best answer was "it probably wont work".
    Your Dad sounds like a smart man. Maybe you should start to listen.

    If you dont have anything useful to contribute, why even take the time?
    Because maybe you’ll learn something.

  3. #16
    Join Date
    Mar 2006
    Posts
    661
    Quote Originally Posted by pecmsg View Post
    Atta Boy for trying to help.

    Was this coil matched to the condensing unit?




    Shorted to ground is usually caused by moisture. Either way something went really wrong.


    4-Ton compressor (48,000 btus) going through a 2 ½-Ton condenser (30,000 btus) think about it.



    Sorry I can’t help with this one. The only thing I can say is you’ve wasted a lot of time, now you’re looking to make it worse. Rip that entire unit out. Line set included. Chalk it up to a Learning Experance
    Am I like stuttering or something. I put in a matching unit, but it was sitting in our trailer for like 5 or 6 years, not pressurized with nitrogen.
    It ran for like 9 months, I assumed that eventually the compressor would give out, but overall he got a darn good deal. Why in the WORLD would I rip the unit out? And the lineset? Worst case scenario I order him a new compressor, and throw in a couple filter/driers. I hope your alot more observant in you're HVAC work than you are in your thread reading/trolling. I feel bad for the people who work under you, how do you respond to their reasonable mechanical/physics questions? I can obviously assume that a correctly sized compressor would work better, I'm not mentally handicapped here, I was asking a question, because I was trying to PREVENT learning from experience. I didnt make any mistake, other than doing cheap work on the side using used equipment, and I dont regret that entirely.
    Last edited by yelram; 02-26-2008 at 06:14 PM.

  4. #17
    Join Date
    Mar 2006
    Posts
    661
    Quote Originally Posted by everythingair View Post
    I would think that the first thing to consider would be the amp draw of the 4 ton compressor. Once you install the compressor along with an appropriate sized capacitor, are the existing wiring and controls going to be able to support it?

    Is the breaker large enough to handle the amp load? Is the wiring large enough? Is the contactor large enough?

    Even if all of the electrical is upgraded to support the larger compressor, is there any way that the coils are going to be able to handle the capacity of refrigerant being pushed into them by that compressor? A metering device can only do so much and I am picturing that little Dutch boy holding back the massive amount of water behind the dyke with his finger.

    Is the indoor coil downstream from the electric heaters? Are the electric heaters allowed to operate at the same time as the heat pump does?

    All in all I would have to agree with your dad.

    The freon capacity was my only real issue, the wires are all big enough, I didnt even bother to check yet if its physical dimensions would allow for it. This one doesent even have an accumulator, so I really doubted it would work, but I figured I would ask on here, assuming that since this is a learning environment, it would be well accepted, which it was by a few.

  5. #18
    Join Date
    Jul 2004
    Location
    Massachusetts
    Posts
    6,837
    So why is one compressor rated 2.5-tons and another one rated 4.0-tons? They look the same, may even have the same size suction line at the compressor. So what gives? It's the bore and stroke of the piston. Just like in a car, the diameter of the piston and the distance it travels determines the capacity of the compressor. So if you put one in that needs a certain volume of refrigerant to 'breathe', then putting it in a unit that can't deliver that volume is just like you putting a plastic bag over your head and poking a 1/4-inch breathing hole in the bag. You'll soon turn blue, fall down, then stop breathing. Same thing with the compressor, except unless it's already blue, it won't change color. But it sure will die. It's all volume, that's what it's all about.
    If YOU want change, YOU have to first change.

    If you are waiting for the 'other guy' to change first, just remember, you're the 'other guy's' other guy. To continue to expect real change when you keep acting the same way as always, is folly. Won't happen. Real change will only happen when a majority of the people change the way they vote!

  6. #19
    Join Date
    Mar 2006
    Posts
    661
    Quote Originally Posted by skippedover View Post
    So why is one compressor rated 2.5-tons and another one rated 4.0-tons? They look the same, may even have the same size suction line at the compressor. So what gives? It's the bore and stroke of the piston. Just like in a car, the diameter of the piston and the distance it travels determines the capacity of the compressor. So if you put one in that needs a certain volume of refrigerant to 'breathe', then putting it in a unit that can't deliver that volume is just like you putting a plastic bag over your head and poking a 1/4-inch breathing hole in the bag. You'll soon turn blue, fall down, then stop breathing. Same thing with the compressor, except unless it's already blue, it won't change color. But it sure will die. It's all volume, that's what it's all about.
    Is there anywhere you can get a good exploded diagram of a scroll compressor? I've ripped a couple apart before, but its still hard to understand the direct mechanical principles involved. I've never had any experience with older non-sealed compressors, so some of the details are hazy at best.

  7. #20
    Join Date
    Apr 2007
    Posts
    6,285

  8. #21
    Join Date
    Nov 2000
    Location
    Eastern PA
    Posts
    68,944
    If the wiring and circuit breaker is properly sized to handle a 4 ton compressor, then it is grossly oversized for a two and a half ton compressor.

    Just taking a WAG here, but may we assume your dad didn't wop you upside the head enough while you were growing up? Just saying that your attitude is way too caustic for someone who is asking some questions that a decent HVAC technician should not be asking and giving data that just cannot be correct. Again, there is no way the same wiring and circuit breaker can be good for both a 2.5 ton compressor and a 4 ton compressor. The contactor and capacitor would be wrong as well.
    Government is a disease...
    ...masquerading as its own cure…
    Ecclesiastes 10:2 NIV


  9. #22
    Join Date
    Mar 2005
    Location
    Suppy NC
    Posts
    4,513
    i say what the hey just put it in and let us all know how long it lasted


    I say 8 hours and it croaks

  10. #23
    Join Date
    Sep 2002
    Posts
    12,459

    This is the problem -

    You will pump away more refrigerant than you can move through the evaporator. This will make the suction pressure run too low. The coil will freeze. A system with a frozen evap will not work. That is for cooling.

    Now then, just to talk some backyard crap, I think if you ran it in reverse-cycle-only for heating you could get away with it for a while.

    And hey! Since the labor and the compressor are free - why not give it a shot and then tell what happened?
    PHM
    --------
    The conventional view serves to protect us from the painful job of thinking.

  11. #24
    Join Date
    Sep 2002
    Posts
    12,459

    The wiring won't matter

    The 4.0 compressor won't be doing any more work than the 2.5 was.

    The capacitor will need to match the 4.0 though.

    I think it will work for heating. Not for cooling as the indoor coil will freeze in cooling mode.

    Suction pressure will run low so it may defrost more. But the head pressure will run as high or higher so the heating capacity will be more dependent on the indoor coil sizing.

    What the hell? In two hours you can have it up and going.

    BTW: with that original unit you installed which had set open - why didn't you change the oil and pull a 500 mike vacuum? Some big driers. Wouldn't it have been OK then?
    PHM
    --------
    The conventional view serves to protect us from the painful job of thinking.

  12. #25
    Join Date
    Apr 2005
    Location
    N. E. Missouri
    Posts
    9,750
    Quote Originally Posted by tinknocker service tech View Post
    i say what the hey just put it in and let us all know how long it lasted


    I say 8 hours and it croaks
    Is this the start of a pool? I'll take 22 hours. (you just never know)
    Do not argue with an idiot. He will drag you down to his level and beat you with experience.

  13. #26
    Join Date
    Nov 2000
    Location
    Eastern PA
    Posts
    68,944
    Quote Originally Posted by mrs reb77 View Post
    Is this the start of a pool? I'll take 22 hours. (you just never know)
    My guess is that it would ice up whichever coil is the evaporator coil (depending on mode) within minutes or overheat the compressor from lack of refrigerant.
    Government is a disease...
    ...masquerading as its own cure…
    Ecclesiastes 10:2 NIV


Page 2 of 7 FirstFirst 1234567 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Comfortech Show Promo Image

Related Forums

Plumbing Talks | Contractor Magazine
Forums | Electrical Construction & Maintenance (EC&M) Magazine
Comfortech365 Virtual Event