Page 1 of 4 1234 LastLast
Results 1 to 13 of 41
  1. #1
    Join Date
    Sep 2007
    Location
    Under the sea
    Posts
    246
    Post Likes

    I need a List of the dumbest things I ever saw

    I've been in the controls business for over 35 years. More than half my life. Lately I'm seeing things that are now scaring the $hit out of me.

    Lets start the list with Heat pipes that have 24 VAC solenoid Valves wired in parallel which draw an inrush current of 3.4 amps each with a holding current of 1.2 amps. No problem until you have about 30 or so of these valves setup for three stage control. The installing electrician spent a few days trying figure out why the circuit breaker on his 75va transformer was tripping. Ended up installing a 2 kVa 24VAC transformer, conduit for the increased wire size. Of-course the control guys get stuck with supplying 30 amp contactors.

    How about the Daikin BACnet interface with 100 or so FCU's connected. 2900 points don't mean a thing when the Daikin start-up guy didn't bother to keep track of which address he assigned to a room FCU.

    A primary variable speed pumping system with bypass valve that's supposed to maintains minimum flow through a Chiller piped from the pump discharge pipe to the chiller discharge pipe. Engineer was worried the return water would get to cold comming back. Solution close and disconnet bypass valve, Install 3-way valve at largest AHUs.

    Don't even get me started on Multi-Compressor Colmac heatpumps with Carel controllers.

    Please feel free to add to list. I cannot believe I'm the only one suffering in PC crap world.
    In case of malfunction-Reconnect brain BEFORE starting mouth.

  2. #2
    Join Date
    Aug 2013
    Location
    Las Vegas, NV
    Posts
    176
    Post Likes
    Although I am not a control tech my award goes to maintenance staff changing a ton of setpoints right after an air balanced and myself have set everything. Talking about minimum flows, K factors, diff setpoints, and other things. I've even seen static set to 21,000. Also setting the schedule to turn on chillers just 30 minutes before the building opens and expect it to be cool.

  3. #3
    Join Date
    Aug 2013
    Location
    Las Vegas, NV
    Posts
    176
    Post Likes
    Air balancer

  4. #4
    Join Date
    Jan 2010
    Location
    Cedar Rapids, IA
    Posts
    93
    Post Likes
    Dunno if I'm allowed to post here, but a contrary to SMS' post is our building being balanced before the air units were running.
    We also have several thermostats 12 inches from a south window, above the fintube, below the air vents.
    There's more, but they're not controls.

  5. #5
    Join Date
    Jul 2001
    Location
    Canada
    Posts
    1,890
    Post Likes
    Air compressor for PNEUMATIC CONTROL SYSTEM removed ( relocated to maint mgrs. side business work shop ) then the pneumatics tyed into air supply for the air tools in the plant , bypassed the dryer and filters. Control system turned into a HYDRAULIC system rather than a PNEUMATIC system as the plant air supply had an oil injector to lube the tools.

  6. Likes bigguy158, BBeerme, JCIman liked this post.
  7. #6
    Join Date
    Dec 2005
    Location
    California
    Posts
    379
    Post Likes
    The dumbest thing I've ever run into? Top ten from memory.

    #1 I saw a whole floor of unit vents with the 277/24 wired backwards. And the electrician turned it on!!
    #2 Supply fan and return pointing at each other.
    #3 Canned manufacture program that turned on the fan, opened the oa damper and closed the hw valve when the freezestat tripped.
    #4 Janitor didn't like the cold air so he decided to unlink the combustion air damper in a school. And bypass the safety.
    #5 Looking for gas leaks with a torch.
    #6 A flat elementary school roof with all the roof drains plugged. Had to clear the drains before walking to the ahu's. The roof was so rotted my fat 170 pounds was enough to cause some of it to cave in at the office.
    #7 Broken sump pump at school. Janitor was using pallets to keep his feet dry to reset the tripping MCC.
    #8 Was sent on a service call to a very expensive private school in NYC. After a few hours I found every single control was in place and but nothing was wired. The install was "completed" years ago and the owners insisted that it mostly worked fine. Getting flustered I ran into an old Polish maintenance man and asked how he controlled this building (8 floors). He brought me down to the basement and walked passed the BMS system to buildings main steam valve. "When building get cold I open, when building get warm I close." With that I said please sign my ticket.

  8. Likes digo liked this post.
  9. #7
    Join Date
    Sep 2013
    Posts
    96
    Post Likes
    Quote Originally Posted by Control Man View Post
    Air compressor for PNEUMATIC CONTROL SYSTEM removed ( relocated to maint mgrs. side business work shop ) then the pneumatics tyed into air supply for the air tools in the plant , bypassed the dryer and filters. Control system turned into a HYDRAULIC system rather than a PNEUMATIC system as the plant air supply had an oil injector to lube the tools.
    Been there on a DDC retro job. First time I had been on site. Cut the first supply tube and got sprayed in the face with oil. Asked my coworker why there was oil all over the VAV cabinet and he started laughing at me.

  10. #8
    Join Date
    Jun 2012
    Posts
    79
    Post Likes
    Support staff in an egg processing facility unplugging the JACE multiple times to charge their phones.

  11. #9
    Join Date
    Jul 2001
    Location
    Canada
    Posts
    1,890
    Post Likes
    I could not access a DDC job remotely , customer ( nursing home ) had changed the phone # on the line provided but never told us , some poor little old lady kept getting weird beeping phone calls all hours of the day / night as we tried to access the nursing homes MODEM as they had switched her over to the # we had used for years

  12. #10
    Join Date
    Feb 2008
    Location
    Washington State
    Posts
    94
    Post Likes
    1.) A piece of copper tubing cut to fit in fuse holder in a MCC Bucket.

    2.) Wire nut between the cover and the heater overload reset, held down by the screwed on cover.

  13. #11
    Join Date
    Apr 2014
    Location
    MN
    Posts
    208
    Post Likes
    Might have figured out why the communication on the MS/TP bus wasn't working.
    The way the wire was laying, the shield was laying across both + and -.
    About 20 of the 24 modules looked this way.


  14. #12
    Join Date
    Jul 2008
    Location
    Melbourne
    Posts
    1,612
    Post Likes
    commissioning 2 new chillers for a big data centre.
    everytime a chiller started and its associated cwp started there was a horrible surging noise.
    The mechanical commisioning guy freaked out at me...he doesnt care why I screwed it up..."just effing fix it", he squealed

    Next morning at 6 am in a little bit of quiet time and under no real cooling load I decided I had better get fixing my er...screw-up.
    about 5 minutes ... after following the common cw pipework I discovered that where the plumbers had cut in the new cw pipwork to the existing cw pipework they had swapped flow and return.

    every thing was fine when no chillers ran...the secondary cwp would circulate water just fine.
    everytime a chiller started... the local cwp was pushing water the wrong direction.
    only 450mm pipes...no big deal

    anyway, since the mechanical commissioning was already finished ( ?? ) and apparently all fine, I had to call in the mech project manager and quietly show him the piping problem. Didnt need to embarrass or make a big deal about it.

    I swear it took me about 1 hr to convince him that it was wrong.

    and this is why everything is a controls problem I suppose ... it does seem that every time the controls people get called in the issues seem to just disappear.

    ...didnt even get a thank you.
    1 + 1 = 3 ( *** for very large values of 1)

    ...everybody wants a box of chocolates and long stemmed rose

    Be brave. You cannot get eaten by an imaginary tiger.

  15. #13
    Join Date
    May 2004
    Location
    SE Pennsylvania
    Posts
    1,271
    Post Likes
    Had a job with a severe communication issue suddenly. Found this done in multiple areas with the slack com wire.
    [IMG][/IMG]

Page 1 of 4 1234 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
  •  

Related Forums

Plumbing Talks | Contractor MagazineThe place where Electrical professionals meet.
Quality Home Comfort Awards