Results 1 to 5 of 5
  1. #1
    Join Date
    Feb 2012
    Location
    Maryland
    Posts
    14

    Confused When were Manual J and D implemented?

    This is more of a curiosity question- does anybody know when Manual J and manual D were implemented originally? My house (1955 built) has central air but I believe this may have been before the days of Manual J and D and the installers just took their best guess.

  2. #2
    Join Date
    Jul 2004
    Location
    Massachusetts
    Posts
    6,841
    I do not know the exact year but what I do know is that it's slowly becoming more common. In 1955 everything was being done by guess and because that's the way they were taught. Today many, most in fact, avoid load analysis and duct design because it takes training and interest and a desire to do the work properly. That's a culture that must be groomed within the company and many will try and fail to live up to the standard. 'Tis a rare company where the rules are followed religiously.
    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
    Feb 2011
    Location
    North East Ohio
    Posts
    786
    Quote Originally Posted by Ed Ww View Post
    This is more of a curiosity question- does anybody know when Manual J and manual D were implemented originally? My house (1955 built) has central air but I believe this may have been before the days of Manual J and D and the installers just took their best guess.
    Are you still using 1955 equipment? I'd like to see that

  4. #4
    Join Date
    Feb 2012
    Location
    Maryland
    Posts
    14
    No the AC and furnace are around 5 years put in by the previous owners but they got cheap and put in a 80% unit The ducts are original though.

    The wall heater I believe is from the 1950s though. You can see the back of it. I don't use it though, the flu slopes down!


  5. #5
    Join Date
    Jul 2004
    Location
    Massachusetts
    Posts
    6,841
    Uh oh! Asbestos wrap on the wall heater vent! DANGER! DANGER! You're going to have to see a lawyer soon for mesotheleoma issues!

    The real beauty of the really old systems is that they had no science but they knew BIG. So they made the ducts really big with really big supply outlets and typically very low static pressures. So they work great even though the old wood and coal furnaces were huge! I've seen some of those old furnaces, some with propeller type belt drive blowers on top. Made of cast iron those old heat exchangers were and they'd outlive everybody if not thrown out for being huge and inefficient. Ah, those were the days.
    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!

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