Page 1 of 2 12 LastLast
Results 1 to 13 of 14
  1. #1

    Twinning of variable speed motor

    1)May I know why twinning of two variable speed motors in furnace is not done?
    2)I also like to know if it is because of lack of tecknology?or customer dont want such twinning on variable speed motor.
    3) Is there any requirement in market which demand twinning of variable speed furnace.
    4)Is there any OEM goodman,trane ,rhim who wants to do twinning on variable speed motor on furnace?

  2. #2
    Join Date
    Jul 2004
    Location
    Massachusetts
    Posts
    6,837
    ECM motors, whether variable speed or constant torque, operate based on static pressure feed back. They need to 'see' static pressure to determine how fast to rotate. Twinning reduces the static to zero, thus one the ECM motors will 'huff' and not turn up to speed. For after market ECM motors that also determine rotation automatically, they may also fail to establish the proper rotational direction. So ECM motors are not twinned, at least with the technology available today.

    It is notable that the various sizes of residential equipment, 40,000 to 140,000 Btu's for gas furnaces and 1.5 to 5.0-tons for AC and HPs is a product of what was considered a large home, average home and small home back in the 1950's. The manufacturers have maintained those sizes quite successfully for many, many years and obviously fail to see why they should increase them for the limited market that needs twinned products. Generally it's very large homes or commercial establishments that have twinned furnaces or air handlers. I reckon they'll have to survive with non-ECM motors until something changes.
    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!

  3. #3
    Join Date
    Mar 2003
    Posts
    1,234
    Carrier is working on twinning with variable speed furnaces that will be avail. in the near future. They will be using ecm motors with the older PWM rather than communicating technology. Not sure of how great the demand is for it but obviously if Carrier is going to have them there must be a market out there.

  4. #4
    Join Date
    Aug 2004
    Location
    North Richland Hills, Texas
    Posts
    14,915
    Monitoring 2 variable speed blower equipped air handlers fighting it out over a common return is almost as entertaining as watching an oversized electronic bypass damper on a zoned system and a variable speed blower fight an ultimately futile battle for equilibrium.
    If more government is the answer, then it's a really stupid question.

  5. #5
    Join Date
    May 2000
    Location
    Indianapolis, IN, USA
    Posts
    34,337
    I don't think it is a problem with the fixed speed ECMs, like the X13. Since they aren't adjusting to duct conditions, they won't fight each other. At least Rheem & Nordyne, 2 that I looked at, say it is OK and have twinning on their boards.

  6. #6
    Join Date
    Mar 2003
    Posts
    1,234
    Quote Originally Posted by BaldLoonie View Post
    I don't think it is a problem with the fixed speed ECMs, like the X13. Since they aren't adjusting to duct conditions, they won't fight each other. At least Rheem & Nordyne, 2 that I looked at, say it is OK and have twinning on their boards.
    Correct, it isnt a problem with fixed speed ecm motors it is the variable speed motors that have not been able to be used. Like I mentioned previously Carrier will soon have true variable speed twinning capabilities using the older design PWM motors that do not communicate.

  7. #7
    Join Date
    Aug 2004
    Location
    North Richland Hills, Texas
    Posts
    14,915
    AS/Trane ForeFront/Hyperion air handlers should be ok for twinning with the motors set for constant torque mode.
    I haven't looked to see if they are specifically approved for it though.
    If more government is the answer, then it's a really stupid question.

  8. #8
    Join Date
    Jun 2001
    Location
    Moore, Oklahoma, United States
    Posts
    4,385
    In residential a home that's so large it needs TWO 140k furnaces probably should be zoned anyways.

  9. #9
    Join Date
    Nov 2001
    Location
    East Texas
    Posts
    918
    20080709-ST-031-08%20York%20Twining.pdf

    Here is a wiring diagram i used last year on two x-13's. Worked great

  10. #10
    Join Date
    Feb 2012
    Location
    Opelousas La.
    Posts
    90
    Quote Originally Posted by mark beiser View Post
    AS/Trane ForeFront/Hyperion air handlers should be ok for twinning with the motors set for constant torque mode.
    I haven't looked to see if they are specifically approved for it though.
    I think the Hyperion vs air handler will revert back to constant cfm in the heating mode even if it is set on torque mode.

  11. #11

    Twinning of variable speed motor

    It seems from above discussion that twinning for variable speed motor have considerable market but because of technical difficulties not coming in market.Is my assumption right?

  12. #12
    Join Date
    Jun 2001
    Location
    Moore, Oklahoma, United States
    Posts
    4,385
    Quote Originally Posted by Rajan1 View Post
    It seems from above discussion that twinning for variable speed motor have considerable market but because of technical difficulties not coming in market.Is my assumption right?
    IMHO the concept of twinning came from old leaky houses combined with contractors fear of under-sizing. If a house needs more than 140k of heat then fix the house instead of figuring out a way to add more heat. 140k of heat should be good for at least 5,000sqft, and at some point ductwork gets too long to distribute air effectively to all rooms. I can't think of any residence large enough that would need to be twinned, but I live in the south. Even commercial could benefit from having separate units in different areas of the business. Besides, most commercial jobs are roof top units anyways...

  13. #13
    Timber,
    Do you still have that diagram. I am looking to twin 2 TM9X Yorks. They have the x-13. The contractor was supposed to install the TG9S but ordered and installed the wrong furnace for the application. Can you help?

    Thanks

Page 1 of 2 12 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