Page 3 of 3 FirstFirst 123
Results 27 to 31 of 31
  1. #27
    Join Date
    Jul 2005
    Posts
    12
    The manual says Furnace Rated at .5" ESP.

    There are some things I don't understand though. In the chart are TAP, LOW, MEDL, MEDH and HIGH. Are these for cariable speed blowers? Having a single speed blower, which do I refer to?

    Also, I'm in the natural gas business and have a draft range differential pressure transmitter than can accurately measure down to a few fractions of an inch. Basically a digital manometer rated at .1% of 30" (0.03" I think).

    Do I tap into the inlet and outlet of the furnace or what?


  2. #28
    Join Date
    Aug 2002
    Location
    Office and warehouse in both Crystal River & New Port Richey ,FL
    Posts
    18,836
    Sounds like you have a multispeed motor,very common,variable speed is a DC motor and different altogether.

    If thats a fan chart it should list cfms,at varios ESP's or static ,for varios fan speeds so you have a choice,higher speed will deliver more cfms at higher ESP's.

    Measure sstatic at inlet to furnace,and note where the filter is located and it's size and type.

    Then measure at a point between the coil and the furnace,Don't drill holes if you don't know what's behind that area!!!

    If you can't get to a pont between the two,measure hust above the coil,and post the model number of the coil,someone may have the specs on the coil.I'm assuming it's a ne coil.

  3. #29
    Join Date
    Jul 2005
    Posts
    435
    Was a load calc done on your home? Unless you live in Arizona under 110 degree heat 5 ton for a 2500sq ft home seems a little overkill! Even though it previously had a 5 ton unit still does not mean it's correct? How is the humidity in the house and did the last unit short cycle?

    [Edited by kevinmac on 08-01-2005 at 10:18 AM]

  4. #30
    Join Date
    Jun 2005
    Location
    SW Wisconsin
    Posts
    5,031
    2500-sq.ft. home, 14-SEER, 5-ton; sounds like the old 500-sq.ft. per ton rule.

    That 16" round return duct is about right for a 2.5-ton system, not a 5-ton system! Even if it had a 4-ton condensing unit on it before, it wouldn't deliver anywhere near 4-ton.

    That could be leading you to oversizing even more, which won't work either. Have a "manual J" done and size it right with a duct system and blower to match the tonnage.

    You need at least a 20" round duct return for 5-tons.

    http://www.udarrell.com/proper_cfm_b..._systems.html- udarrell

  5. #31
    Join Date
    Aug 2002
    Location
    Office and warehouse in both Crystal River & New Port Richey ,FL
    Posts
    18,836
    After the Man. J,get a Man . D ,duct design,and you'll find the correct sizes for Your duct system,it can vary ,a lot.

    20" could be right so could 22 or more.

Page 3 of 3 FirstFirst 123

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