Results 1 to 10 of 10
  1. #1
    Join Date
    Jun 2004
    Location
    4H: Hot, Humid Houston H.O.
    Posts
    3,304

    5-2-1 Solution, or snake oil?

    There is a gadget called "5-2-1 Compressor Saver" which claims to protect your machinery and save electricity:
    http://www.garyontheair.com/521.php

    I sure would like it if some pros would look that over and tell us whether the claims are bogus. My thinking is if there really is a problem, and the solution is that easy, the manufacturers such as Trane are ethically obligated to include it in their products already. Am I off base?

    Thanks in advance -- Pstu

  2. #2
    Join Date
    Sep 2005
    Location
    Texas
    Posts
    2,793

    its just a start kit...

    ...they should be put on in some cases, like when the evap coil has a TXV

  3. #3
    Join Date
    Jan 2003
    Location
    Kansas City
    Posts
    1,482
    Hard start kits are rarely included with new equiptment anymore due to scroll compressors and cost considerations. The contractor who installs the system determines if this optional device is needed.

    Ethically responsible eh?...Remember when spare tires and rear bumpers were options on new pick up's?

  4. #4
    Join Date
    Aug 2006
    Posts
    112
    hard start kits are not necessary to make the system start and run. manufactures are woried only about the equipment lasting through the warranty period, with as little money spent to do it as necessary. as a dealer it is up to us to sell the customer on an upgrade by explaining the benefits. as a tech i think every system sold should have a hard start kit installed. 95% of the scroll compressors i have replaced have not had hard start kits installed. 95+ % of the units installed with hard start have never had any issues. 5-2-1 refers to the terminal conections on the potential relay used to switch the capacitor out of the start winding circuit after the compressor is up and running.

  5. #5
    Join Date
    Jan 2001
    Location
    So.Cal
    Posts
    447
    5-2-1 is a 3 wire hard start kit. If you need start assist I would choose the 3 wire hard start over the 2 wire booster you parallel into the run cap.

  6. #6
    Join Date
    Aug 2003
    Location
    Fort Worth, TX
    Posts
    11,347
    Remember the old line for memorizing how to hook up a start capacitor with potential relay? 5-2-1, Common, Start, Run. Looks to me it's just a start cap with a pot relay and a lot of razzmatazz making it sound like cutting edge technology. Some old tech was showing me how these things work back in the seventies. Nothing new or razzmatazz about it.

    "Hard start"...often refers to when a compressor that normally started for years on just a run capacitor now needs additional torque to get it running. This is a sign the compressor is in trouble and may not live long.

    "Start assist" is for reciprocating compressors that are on a system with a non-bleed thermostatic expansion valve. They need extra torque to overcome higher pressure sitting on the compressor cylinder head at startup, being that the system does not equalize during the off cycle.
    • 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.

  7. #7
    Join Date
    Aug 2004
    Location
    North Richland Hills, Texas
    Posts
    14,914
    Trane installs a hard start kit on all of their units that come with a recip compressor, and many of the heat pumps that come with scroll compressors.

    The 5-2-1 brand start kits look good, but the potential relay can't handle continuous coil voltages in the 400v+ range.
    I put 20-25 of them in over the course of a year and had several fail. In all cases where they failed, the voltage between start and run for the compressor was >400v.
    The makers of generic start kits REALLY should list, on the package, the continuous coil voltage the relay can handle.

    Oh well, I just went back to matching up a potential relay to the operating characteristics of the compressor and building my own stat kits like I always did before.
    Maybe some day someone will market a generic start kit that is good for more than just troubleshooting, or getting a compressor running so I can get the readings I need to size a real start kit.
    I won't be holding my breath though.
    If more government is the answer, then it's a really stupid question.

  8. #8
    Join Date
    Aug 2004
    Location
    North Richland Hills, Texas
    Posts
    14,914
    Quote Originally Posted by shophound View Post
    Remember the old line for memorizing how to hook up a start capacitor with potential relay? 5-2-1, Common, Start, Run.
    Or "2 s1r 5 c", say it as "2 sir 5 c".
    If more government is the answer, then it's a really stupid question.

  9. #9
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    68,114
    Quote Originally Posted by pstu View Post
    My thinking is if there really is a problem, and the solution is that easy, the manufacturers such as Trane are ethically obligated to include it in their products already. Am I off base?

    Thanks in advance -- Pstu

    Ads such as this make people think there is a problem when there isn't.

    All straight A/C units would benifit from suction accumilators.
    But you won't find them in a/c's.
    Capacity limiting devices would help to stop short cycling, you won't find them either.

    If all things benifical were added, you would be paying the same for a low end unit as you do now for the higher line units. And the higher end units would go up even more then they are now.
    Contractor locator map

    How-to-apply-for-Professional

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

  10. #10
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    68,114
    Richarddmcmurray, this is the Ask Our Pro's forum, and only Pro members that have been vetted by the AOPC may post advise here. Please apply to the AOPC today, thank you.

    You can find the rules for posting and qualifications here.


    Further infractions may result in loss of posting privileges.
    Contractor locator map

    How-to-apply-for-Professional

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

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