Page 6 of 7 FirstFirst 1234567 LastLast
Results 66 to 78 of 80
  1. #66
    Join Date
    Oct 2003
    Location
    southern mo.
    Posts
    323

    Thumbs up

    yelram,i gotta a 3 ton copeland and a 3ton intertherm coil down here in mo. , your welcome to them for a case of beer, if you pick them up!!{of course they are used}.you gave your buddy a deal and no good deed goes unpunished. some of you all need to lighten up..........

  2. #67
    Join Date
    Apr 2004
    Location
    Des Plaines,IL
    Posts
    1,016
    Yelram, if you really want to find out what will happen when you put a 3.5/4.0Ton compressor in a 2.5Ton system, then the best way to learn is to do it yourself(if you have the time). Since you claim to have ten years of experience, then you should know about superheat and subcooling when it comes to charging up systems. This should give you an idea of what will happen when you put the oversized compressor it the system. One of the reasons that you are not getting a specific answer is that this falls under the category of being a "Franken" system and therfore the results from a "grossly" mismatched system are very unpredictable.
    Stuart
    Lack of airflow destroys compressors.

  3. #68
    Join Date
    Mar 2006
    Posts
    661
    Quote Originally Posted by mcewans View Post
    Yelram, if you really want to find out what will happen when you put a 3.5/4.0Ton compressor in a 2.5Ton system, then the best way to learn is to do it yourself(if you have the time). Since you claim to have ten years of experience, then you should know about superheat and subcooling when it comes to charging up systems. This should give you an idea of what will happen when you put the oversized compressor it the system. One of the reasons that you are not getting a specific answer is that this falls under the category of being a "Franken" system and therfore the results from a "grossly" mismatched system are very unpredictable.
    I have ten years of experience in the field, not specifically in heatpumps. Alot of it is sheetmetal work, gofering on service calls (80% of those oil), roughing in houses, boiler systems, and mainly installations. One of our top employees quit to start his own business about 3 years ago, and since then I have had to do alot more with them than before. I know about superheat and subcooling, and I understand that the surface area of the coil is critical in exchanging the cold(or warm) air temperature with that of the freon. What I did not know is if there was some way to trick it, either electronically or mechanically. I bet with the correct low voltage controls you could make it work, but it would be turning on and off all the time. I will take getting paid to learn on the job over paying to learn any day of the week. If I was worried about getting hired somewhere, I would probably go to school just to get the piece of paper, but work for me is more obligatory. I cant quit. Most of our customers have known me since before I can remember knowing them, so I kind of have a cushion for learning so to speak.

  4. #69
    Join Date
    Sep 2002
    Posts
    12,280

    Sure - there is a way to trick everything

    Heat pumps, air conditioning, refrigeration - it's all the same basic stuff - just combined in various ways.

    I was pondering for a time how this thing of yours could be successfully done. In a non heatpump system you could install an EPR valve in the suction line and set it for 65 lbs. Done. Let the head pressure float.

    But in a heat pump it would be more complicated. The EPR valve would have to be in the suction line at the indoor coil and you would have to pipe a check valve in parrallel with it but in reverse flow to the EPR valve. An alternative would be a NC solenoid in parrallel with the EPR with the coil powered for heating.

    And unless you have all that stuff laying around too, and lots of idle time, and are in AA - why bother? Get your pal to spring for a 2.5 compressor and put it in there with all new electrics and driers. Done and no fiddling around.

    Sure I can do it. But how many times am I willing to prove it for free? That's the real question. <g>
    PHM
    --------
    The conventional view serves to protect us from the painful job of thinking.

  5. #70
    Join Date
    Feb 2007
    Location
    18951
    Posts
    1,593
    Quote Originally Posted by yelram View Post
    I would probably go to school just to get the piece of paper,
    Don't go to school for a piece of paper unless you want to become a mechanical engineer and work for someone. Go to school for the knowledge. A good place to start is RSES if you have a chapter in your area.

  6. #71
    Join Date
    Mar 2006
    Posts
    661
    Quote Originally Posted by bobb25 View Post
    Don't go to school for a piece of paper unless you want to become a mechanical engineer and work for someone. Go to school for the knowledge. A good place to start is RSES if you have a chapter in your area.
    If I goto school it will be for engineering at a university, and it wont be for quite awhile. And maybe you didnt realize this, information is free. Yeah, totally free. If you're paying for it, thats your business.

    Poodleheadmikey - This EPR valve, how common are they? I've never seen one in my work, I imagine they are more of a refrigeration control? I have a couple solenoids. Like I said, I didnt think it was entirely feasible, but more of a quandry. Like whats the sound of one hand clapping.

  7. #72
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,910
    Go to compressor manufactureres web sites.

    You should be able to find their LB per minute rating.

    On average a compressor for comfort cooling, moves 2.8lbs per minute.(close enough for this explanation) To get its rated capacity.

    So a 2.5 ton would move 7 lbs per minute, and a 4 ton move 11.2

    The ID coil in heating mode won't have enough area to reject the heat. Nor will it have enough air flow if the blower isn't a 4 ton blower.
    The OD coil is also too small now, and also has low air flow for the 4 ton compressors flow rate. So it will ice up, and before the defrost board goes into defrost, the compressor will be flooded with liquid refrigerant.

    It will have the same basic problems in cooling if it survives long enough to get to the cooling season.
    Contractor locator map

    How-to-apply-for-Professional

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

  8. #73
    Join Date
    Feb 2007
    Location
    18951
    Posts
    1,593
    Quote Originally Posted by yelram View Post
    If I goto school it will be for engineering at a university, and it wont be for quite awhile. And maybe you didnt realize this, information is free. Yeah, totally free. If you're paying for it, thats your business.
    Yes, information can be free. I paid for school, but I kept the books. I also have hundreds of other books, and keep several on my truck. No one can know everything, you just need to know where to go to get the right info. My laptop doesn't always pick up the internet on the road, but I have a database of over 8K businesses that I can get phone numbers to call. On the internet, the correct information costs the same as the wrong information. JMO, not trying to argue.

  9. #74
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,910
    Quote Originally Posted by bobb25 View Post
    On the internet, the correct information costs the same as the wrong information.

    Actually, the correct information cost less. .
    Contractor locator map

    How-to-apply-for-Professional

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

  10. #75
    Join Date
    Feb 2007
    Location
    18951
    Posts
    1,593
    Quote Originally Posted by beenthere View Post
    Actually, the correct information cost less. .
    Using the correct information costs less.

  11. #76
    Join Date
    Sep 2002
    Posts
    12,280

    EPR - Evaporator Pressure Regulator - very common

    It won't let the evaporator pressure fall below the set-point of the regulator. Set it for 65 lbs and the indoor coil won't freeze.

    After the EPR the compressor suction pressure Will fall though. The reduced suction gas density will reduce the pumping capacity of the compressor to match the capacity of the indoor coil.

    This will reduced the pounds of refrigerant pumped per minute and make the condenser the right size to reject the reduced amount of heat.

    When you go over to heating, the outdoor coil pressure will run very low; also reducing compressor pumping capacity, but freezing the outdoor coil is normal in heating anyway.

    But . . . before you start on this thing you may want to price a 2.5 ton compressor. <g>

    I have made some wild stuff run. Sometimes because there was no option, and sometimes just to amuse myself, and sometimes just to prove I could.

    Why do you want to do it?
    PHM
    --------
    The conventional view serves to protect us from the painful job of thinking.

  12. #77
    Join Date
    Mar 2006
    Posts
    661
    Quote Originally Posted by Poodle Head Mikey View Post
    It won't let the evaporator pressure fall below the set-point of the regulator. Set it for 65 lbs and the indoor coil won't freeze.

    After the EPR the compressor suction pressure Will fall though. The reduced suction gas density will reduce the pumping capacity of the compressor to match the capacity of the indoor coil.

    This will reduced the pounds of refrigerant pumped per minute and make the condenser the right size to reject the reduced amount of heat.

    When you go over to heating, the outdoor coil pressure will run very low; also reducing compressor pumping capacity, but freezing the outdoor coil is normal in heating anyway.

    But . . . before you start on this thing you may want to price a 2.5 ton compressor. <g>

    I have made some wild stuff run. Sometimes because there was no option, and sometimes just to amuse myself, and sometimes just to prove I could.

    Why do you want to do it?
    I dont really, but it would surely be for amusement.

  13. #78
    Join Date
    Mar 2006
    Posts
    661
    Quote Originally Posted by r22jjc View Post
    yelram,i gotta a 3 ton copeland and a 3ton intertherm coil down here in mo. , your welcome to them for a case of beer, if you pick them up!!{of course they are used}.you gave your buddy a deal and no good deed goes unpunished. some of you all need to lighten up..........
    I might end up taking you up on that deal. I'll let you know.

Page 6 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