Page 2 of 3 FirstFirst 123 LastLast
Results 14 to 26 of 28
  1. #14
    interfacing thought the LCI board.

    Over $200,000 in damage first estimate.... lawyers are in hot pursuit already.

    osiyo - been doing it for years. Just venting, not griping about what i do just the methods the industry has taken to get things done. I love doing all kinds of controls, but these kinds of things take all the fun out of it.

  2. #15
    Join Date
    Aug 2009
    Posts
    2,459
    I'd steer the lawyers directly to Trane. If factory controls allowed the unit to die- it's a factory defect that the factory should be paying for.

    I know- Having written factory firmware for RTU's before that was always the threat that kept us from allowing bugs into the field.

  3. #16
    Join Date
    Mar 2003
    Location
    NY
    Posts
    2,129
    Just wondering.... are these frozen coils IN the RTU or some place else? If in the RTU then there should be glycol in the system. That would be a problem for the engineer. If someplace else then maybe you might want to keep the phone number of your lawyer handy as well.
    "Controls is a lifestyle not a job" -klrogers

  4. #17
    Join Date
    Aug 2007
    Location
    Western Colorado
    Posts
    497
    As the "software" guy I insert a bit of logic to back-up my freeze-stats. (Can't always count on the installers putting controls in the correct location.)If the D/A gets low enough I open both valves. Heat to 100% and Cool to somewhere from 50 to 75%.
    RealEyes
    Realize
    RealLies!




  5. #18
    Join Date
    Mar 2007
    Location
    State of Confusion
    Posts
    1,210
    Quote Originally Posted by Control Doctor View Post
    interfacing thought the LCI board.

    Over $200,000 in damage first estimate.... lawyers are in hot pursuit already.

    osiyo - been doing it for years. Just venting, not griping about what i do just the methods the industry has taken to get things done. I love doing all kinds of controls, but these kinds of things take all the fun out of it.
    ok. Is the train running the train OR are your controls running the train(through GBAS). Something has to control D.A. temp,pressure,reset,etc.
    If trane isn't controlling the train forget the lawyers.

  6. #19
    Join Date
    May 2007
    Posts
    730
    I just did a little reading in the Intellipac IOM and the Programming Guide, really just hitting the high spots. There is a Supply Air Low Limit function that drives the OA toward minimum when SA drops below setpoint. Hydronic units are supposed to have a Low Air Temperature Limit (manual reset). When the Low Limit trips, software drives water valves open, OAD shut, and fan off. After checking the configuration/setpoints I would force a shutdown at the Low Limit and see what happens. These units are kinda funky for OAD adjustment, too. The particulars are in the IOM, but it boils down to if you adjust the OA side of the linkage to be fully open at 100% OA it probably won't shut fully at 0%.

  7. #20
    Join Date
    Mar 2007
    Location
    State of Confusion
    Posts
    1,210
    Thats right but I don't think this is a hydronic heat unit. He said trane was there to reset the heater. Which is gas. That would be a "reheater". To me it sounds like the unit needs commissioned properly and the gas heater fixed.

  8. #21
    Join Date
    Jan 2002
    Location
    Fort Worth\Dallas, Texas
    Posts
    1,694
    Quote Originally Posted by maxpower View Post
    ok. Is the train running the train OR are your controls running the train(through GBAS). Something has to control D.A. temp,pressure,reset,etc.
    If trane isn't controlling the train forget the lawyers.
    He is not using GBAS, he is interfaced through the Lon LCI card.
    Go Rangers!

  9. #22
    Join Date
    Jan 2005
    Location
    steeler nation
    Posts
    2,027
    intellipacs used to have two sets of terminals, one was external start/stop that would do a soft shutdown and another set of emergency shutdown terminals that do a hard shutdown.

    the damage has already been done once, but i would be damn sure it doesn't happen again by tying a freeze stat into the emergency shutdown terminals. (if they still have them). if your worried about the unit getting too cold when unoccupied remote mount it in the building.
    IV IV IX

    use your head for something other than a hat rack.......Gerry

  10. #23
    Join Date
    Nov 2006
    Location
    New Hampshire
    Posts
    255
    The bigger issue is that the unit was discharging 20 deg air and the setpoint was 60 with the OA dampers 100% open. It seems, from the Control Doctor's attached graphic that the OA flow station for minimum OA control is malfunctioning as it is reading 0 cfm with the dampers 100% open. It is obvious that the dampers are physically open by the low discharge air temp but the unit thinks it is not reaching its minimum OA setting thus opening the dampers 100%. You need to get Trane to fix this first.

    I do agree with most of the others that the units are what they are and you (as the controls guy) need to add whatever extra parts and pieces necessary to fully accomplish the specified sequence of operation. I also like to add freezestats on units like this if I have VAV boxes down the line with HW coils to prevent things just like this. Usually you need to locate it inside the building to keep it from tripping while the unit is off. I have done it in software as well so I can put a timer on it during startup to give the fan a chance to get up to speed and get that slug of cold air out of the way. Just my $.02

  11. #24
    Join Date
    Mar 2008
    Posts
    82
    Quote Originally Posted by Control Doctor View Post
    The OA flow meter (internal to the unit) froze up (its -15 degrees here) so it was reading 0 OA CFM.
    Sounds like the local factory rep sucks, not the equipment.

  12. #25
    Join Date
    Mar 2007
    Location
    State of Confusion
    Posts
    1,210
    Quote Originally Posted by Control Doctor View Post
    interfacing thought the LCI board.
    The unit's (Human Interface) Trane panel needs configured with the bas. Usually this is done on start-up day.

  13. #26
    Join Date
    Oct 2003
    Location
    Minnesota
    Posts
    1,337
    Quote Originally Posted by Control Doctor View Post
    osiyo - been doing it for years. Just venting, not griping about what i do just the methods the industry has taken to get things done. I love doing all kinds of controls, but these kinds of things take all the fun out of it.
    Understand the venting, have done it myself.

    A couple years back we did a job for a high dollar retail store. Hanging units, way up on tall ceilings, HW and CW coils, econ cycle, etc. Units had their own controls. We essentially just did S/S scheduling, monitored space temps, and provided means for remotely changing space temp setpoints. Then provided web services for remote viewing and changing of SP's.

    The grand opening day for the establishment was a week before Christmas. As I said, this was a high dollar joint. Premium sports gear, designer sports clothing, etc.

    Got a call the morning of their grand opening, from a very pi**ed off general manager. Water, water everywhere. Of 8 units, 3 had burst coils.

    Gets a trifle nippy from time to time here in Minnesota. I forget the OA temp that day, but it was well below zero, somewhere around 18-20 below Fahrenheit, IIRC.

    <Shrug> Units had their own controls. Startup and commissioning by factory reps. Design for the system was by the customer's own HVAC engineer. A nation wide retailer, they used the same HVAC engineering firm for all their stores.

    Of course, the members of the engineering firm concerned weren't answering their phones that morning. A week before Christmas, newly paid checks probably cashed and the money burning holes in their pockets. Factory reps gone home, not answering the phones either.

    So I got to show up and take the heat.

    Not the first time, so they weren't getting a virgin. I listened while the general manager of that store and some vice president of whatever from the corporate office (who was there for the grand opening) did more than a little of their own venting. I listened patiently, didn't take it personal. Figured they had a right to be ticked off in a major way.

    After, I started going around, taking a close look at things.

    To begin with, for several of the units there was just a very, very short run between the OA dampers and those coils. Stand in the mixing box, spread your arms out opposite each other as far as yah can, you could touch the OA dampers with fingers of one hand, and the first coil with fingers of the other.

    You just were not gonna get much mixing before the stratified air stream entered those coils. Add, those were about the cheapest OA dampers money could buy. Add that the surface area to be covered by the installed freeze stat was very large. There were a lotta large areas not covered where stratified cold air streams could get through, and they did. MAT sensor was just a single point stick type. Same with DAT.

    And it turns out their favorite HVAC engineer doesn't believe in using glycol.

    <Shrug> So what was I to do?

    Wrote up my observations and suggestions. Expressed my deepest sympathies. Made it clear it wasn't OUR mistakes that caused the issue. Then helped with things like cleaning up some of the mess, closing isolation valves, boosting SP's on the remaining, working units, etc.

    Owners called in a service tech from an independent mechanical outfit, he looked around, came to the same conclusions I'd arrived at. Then he set about fixing burst areas as best he could in a hurry. With owner's go-ahead, I checked DAT and MAT sensors, we had some adequate replacements in the shop that were long, averaging types. I had a guy bring em out, and between him, myself, and the mechanical service guy we replaced the existing. I also had our guy bring out some extra freezestats which we installed in series with the existing, the new ones being put into the discharge air streams.

    Got stuff running for them. But I told em that the OA dampers really needed upgrading and they needed to lean on their design engineer and have him reconsider his objections to using glycol.

    <Shrug> Right now I'm dealing with an issue on a new building, that's supposed to be a showcase of efficient energy design and usage. Design engineer calls for a couple things in his specs which just aren't working out. One of which is that we're supposed to be able to turn down the firing rate on some water boilers to 10%. That's a no go. The boilers he called for and bought (have their own internal controls) won't do it without faulting out. Also he calls for a maximum of 155'F HW supply, as reset by OAT when it's minus 20 outside.

    <Shrug> A max of 155'F isn't doing it. Cold complaints all over the building, even with VAV reheat valves wide open when it 10 or 15 below outside. With AHU DA temps of 62'F which is the max the designer wants.

    LOL ... so of course the occupants think we're a bunch of hacks who can't do controls right. But the fact is, we're operating the system EXACTLY as he spec'd us to do it. We even had a balancer double check all air and water flows. They're as called for in the design.

    So what do yah do?

    In our case, I told em to get hold of their designer, and ask him WTF. Kinda hard to do right now as he's on vacation someplace warm. In the meantime I showed customer's maintenance guy how to change SP's to whatever he thinks he needs them to be.
    A site where I stash some stuff that might be interesting to some folks.
    http://cid-0554c074ec47c396.office.l...e.aspx/.Public

Page 2 of 3 FirstFirst 123 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