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  1. #1
    Join Date
    Jun 2006
    Location
    Mount Airy, MD
    Posts
    89

    AAON RTU's used with Water Source Heat Pump for School

    I just had a meeting today with the Contractors installing this AAON RTU with a Water Source Heatpump & asked them about irregularities about the integration Points & Names of Points through BACnet integration with the JCI NAE 55.

    Here is the Problem that I have;
    All of the Points that I can import to the NAE BACnet Field Bus, are those used for a Constant Volume Unit with a Modulating Heat Output & a Modulating Cooling Output. Now since I am Trend/History Happy as a Representative for my School Systems Construction Department, I want Change of Value Trends on every point (physical & psuedo), so that I can troubleshoot the Systems myself before accepting them.

    With the Units setup for the above mentioned Water source HP, the ModCool output is opening or rising frorm 0% to 100% and the Discharge Air is rising with it, which indicates to me that it's in Heat mode, but there is no point given that was imported that is called a Reversing Valve Position point. Also, there is a HeatMod output point that is really not used.

    I was told by the AAON Rep that the P-Link handheld will show the correct points and that JCI can use that to rename all the NAE imported Raw data points to their correct names & then he should remove any unused points.

    My Concern is that when I go to the NAE Field Bus Engineering tab for a backdoor view, I will still see the wrong names for points and missing Points mentioned below. Is this the final word on these AAON Units, that it is what it is and that we have to accept the wrong names for Points? Is there a way to make the seller of the Units to have the correct naming conventions for his points over BACnet.

    I have Building Pressure Control that is missing, but AAON Rep says these can be added.

    One more thing is that we are still owed a CO2 Sensor in the Space to control the amount of Outside Air entring the Gym & Multi-purpose rooms & I cannot find a Point for this.

    Ultimately, Have I been told the truth or did the Contractor order the wrong board for BACnet communication? I have the documentation for the BACnet Standard Points that I am used to in a binder with object #'s in the Hundreds. The object numbers I'm importing are in the thousands & can't be found in my PT-Link-BACnet Tech Guide with Appendix A thru F covering several different types of AAON Units, but not the one's I'm talking about.

    Thanks ahead for any info that anyone has on these AAON's of which I am not too fond of.
    "Please, Do Not Shoot the Messenger!!!"


    "It is not what you Know, but rather, Knowing where to find the answer when you need it"

  2. #2
    Join Date
    Aug 2011
    Posts
    75
    The PT link is wattmaster. I would try to call them with any questions regarding the PT link and points communicated over it.

  3. #3
    Join Date
    Jun 2006
    Location
    Mount Airy, MD
    Posts
    89
    Thx Daninboston,
    Good advice to call watt master direct, since I am the owner & want to know exactly what we are getting & if it meets our Ed Spec's.

  4. #4
    Join Date
    Mar 2003
    Location
    NY
    Posts
    2,145
    Calling Wattmaster is a good idea, they are easy to work with. On the other hand their controls are not so easy. What you are experiencing is typical of Aaon units with these controls. There always seem to be a lot of 'setup' involved after the installation even though you thought you spec'd and were promised everything that you wanted. I wonder who is to incur the cost of having JCI rename all of the points for you? It should be the distributor that sold the Aaon equipment, but don't hold your breath. As far as being able to 'add' devices or points goes, good luck with that. These controllers usually have a limited number of extra I/O. When I have had rooftops used for make-up air units and expected a supply air temperature sensor I was told to add one and tie it in to the input for the return sensor or something of the sort. Yes, you can add these but it is usually at the expense of something that you already have.
    I'm afraid that your frustrations are just beginning.
    Good Luck!!
    "Controls is a lifestyle not a job" -klrogers

  5. #5
    Join Date
    Apr 2007
    Location
    Seattle
    Posts
    42

    AAON uses a Field Server card

    The AAON uses a field server card to translate the Wattmaster controls to BACnet MSTP. You can upload the “table” in the Field Server and edit the file, I think its a CSV file. It’s kind of a lot to do to change the point names, but it can be done.
    If you are trying to anything more than basic stuff with the AAON you are going to have to write some control logic in the NAE and trick the AAON in to doing what you want.
    Good Luck!

  6. #6
    Join Date
    Jun 2006
    Location
    Mount Airy, MD
    Posts
    89
    Quote Originally Posted by dapper View Post
    Calling Wattmaster is a good idea, they are easy to work with. On the other hand their controls are not so easy. What you are experiencing is typical of Aaon units with these controls. There always seem to be a lot of 'setup' involved after the installation even though you thought you spec'd and were promised everything that you wanted. I wonder who is to incur the cost of having JCI rename all of the points for you? It should be the distributor that sold the Aaon equipment, but don't hold your breath. As far as being able to 'add' devices or points goes, good luck with that. These controllers usually have a limited number of extra I/O. When I have had rooftops used for make-up air units and expected a supply air temperature sensor I was told to add one and tie it in to the input for the return sensor or something of the sort. Yes, you can add these but it is usually at the expense of something that you already have.
    I'm afraid that your frustrations are just beginning.
    Good Luck!!
    Thanks for your candid opinion, which is 1 that I share with McQuay RPS Units as well. Since I started working with the School Board here in Howard County, MD, I have had much time to read the Manuals and go behind Contractors after they have walked away and the Warranties are over. We have received some real dingers over the years and it is painfully obvious that I know more about the Distributers Product, then there Service Team, since they set everything up as though it is a Constant Volume Unit. They even set the Warm-up Setpoint at the same Temp as the Occupied Heat Setpoint, which is a big No-No. On VAV Units, they cannot grasp that when they select the Return Air Temp Control Source (like they should), to be set at 70.0 & 74.0 F per CV Unit parameters, that they are forcing the Heat Enable & Cool Enable to be locked out when they are still needed. they cannot grasp that a VAV Unit is Primarily a Cooling Only Unit & that the Preheat Coil is there for 2 things; 1 - To bring the Minimum OA Mixed Air Temperature up to the Discharge Air Setpoint or a couple deg below & 2 - which is to Supply 70.0 ~ 75.0 F Discharge Air to the Spaces during Optimum Start & Warm-up (must keep low to allow the rooms that do Not need Heat from Over Heating, as the VAV's are expecting Cold DA Air & will operate in Reverse, thus Overheating Spaces) Modes of Operation. I am the type of Control Man that has seen too many of our Schools sit and ruin in Warm-up mode for 2 weeks straight because there is a Link to the VAV's calling for Warm-up and that a Integration Link connection will then cause the VAV Box to Close its Reheat Valve 0% & Open the Damper to a 70% position. Now if you have a Pneumatic Background, you know that this does not work & that it is a DDC Controllers ASHRAE Standard that calls for this to occur.
    SUMMARY regarding the Optimal Start/Warm-up mode;
    - The reason why most cheaper Roof Top Units are No longer able to Heat the Spaces below is because of an inherant move by Engineers to Design Systems as small as they can to get Props by the Customer & some will even Design with Diversity in play (Idea is that not all VAV's Dampers will need to be Open 100% at the same time, thus a smaller Unit in their minds is feasable). Problem is that this is OK if your Building Runs 24/7, but Schools do Not & they are typically OFF 2/3rd's of the week or more based on Holidays, etc...
    - The Mechanical Engineers are Failing the Customers and are never held responsible for their screw-ups, EVER!!! They will even cover for each other, as proven by a series of Close out meetings where our Top Dog held meetings to ask why our Schools are Not Comfortable & they Blame everyone but themselves. I am the Only Voice with 1st hand experience of developing Workarounds and make Controls function to the best of my ability. However, I am the Pilgrim in the room shot full of arrows, because all of our Cx Agents fall silent, along with every contractor down the line. TAB, Controls/BAS, Mechanical, etc.. will not speak tyo back me up as they fear that they will be written out of the Design Engineers Specs. What a very sad State of things, & I do not see them changing.
    - McQuay RPS Roof Top Units that do not operate per their own Operation Book and at times will not even control the Heat or Cool Valves because they actually do not have enough outputs to change the Heat type & to modulate Heat Valve Position Control (Uses Floating to Modulate for all outputs, which are Floating Control, NOT Proportional, requiring 2 Outputs each) when the OA Temp rises above 37 deg F, even though it says that you can choose between a Flooded Hot Water Coil and use Face & Bypass Only to Control the Discharge Air Temp 'or' you can chose the Heat Changeover method which will utilize Proportional Heat valve Control above 37 F OA Temp and then when the OA Temp drops below 37.0 F, the Heat Valve will now Flood the Coil and the Face & Bypass will modulate to control the DA Temp. This will not work if you use a Supply & Return Air Fan, VFD's for both, Dx 2-Staged, Mixed Air Damper, and feedbacks. You may find this yourself, in that the Wiring Diagrams (Actually Opens Heat Valves on a Heat Enable, when it should simply just put the Valve in stand-by until Heat is needed) shows that Proper Heat Enable & Valve Control Changeover is impossible because all BO are used and there needs to be 1 more Binary Output to change how the Heat Valve works. When we found this out on one School due to my insistance on all points having Change of Value Trend/History's made and sent to repository, we found that the Valves could only control in 2-Position, as the McQuay Start-up guys ultimately wired the Valve Actuators wrong, to the point that Power was Turned On or Off to Proportional Controlled Heat Valves. What made matters worse, was that 3 RTU's had Honeywell 4 wire Proportional Actuators & 4 RTU's have JCI Valve Actuators , which used 3 wire Prop Control. After working to fix the operation of the Heat Valves for a whole very cold day & into the night, my help & I crossed out the McQuay RPS Heat wiring Diagram & I redrew a wiring diagram that would operate the Heat Valve with the Face & Bypass, when there was an actuall call for Heating.
    **This is a true story and is a common problem, & it did not stop there. Our F&B Damper Actuators were not closing the Face Damper Completely, thus overheating the Spaces below and wasting energy, so we looked into these mountings & Actuator operation & found that the Actuator moved 33% before moving the damper & that the mounting plate only had 1 screw mounting the riser plate to the deck Deck.
    **All McQuay Actuators are Not Controlled Proportionally, but in a Floating Mode, which JCI calls Incremental, which somehow fools the Engineer into accepting them. Strange considering the definition of Incremental as it does not modulate & that we require for All Actuators on Projects to be Proportional (0-10 Vdc). Floating (Incremental) Actuators are almost impossible for most HVAC Tech's and a lot of Control Tech's to troubleshoot, because they believe that they can use their DC Voltage meter to check it out, when in fact that shows those of us who know that they operate back and forth based on the motor time and the closure of a Close Relay and the Closure of a Open Relay. NOTE This type of Control really has a big problem with floating off center & the Controller usually has no idea, so Manufacturers typically put in a self Calibration every 24 Hours, but they can float of cal in less time. The only Application that Floating (Incremental) actually works and is acceptable is for VAV Damper Actuators because the Actuator is not controlled to a position, but to a Flow setpoint.

    Enough said or this will be a Novel.

    Thnks for your responses everyone, as I will take your good advice,
    BigdogTim7
    "Please, Do Not Shoot the Messenger!!!"


    "It is not what you Know, but rather, Knowing where to find the answer when you need it"

  7. #7
    Join Date
    Jun 2006
    Location
    Mount Airy, MD
    Posts
    89
    As the Customer, we feel that we paid for the correct Naming, as though we bought a Hybrid Car, in that we want it to run correctly and understand all of the Controls by reading the users manual, or we are in the dark as much as the installer. So then, who do we call to Service it?

    We already have JCI & Niagara Framework Contractors writing minimal programs, such as shutting the OA Dampers during Optimal Start & to link the associated Space Exhaust Fans.

    We really want all of our Controllers to Operate in Stand-Alone mode if the Comm Bus goes down in a School, with Systems containg a Pipe Aquastat on 2-pipe Systems to maintain automatic changeover, along with an OA Sensor if needed for Stand-Alone Control on Dx Units where the On Board OA Temp is used as a default temp if Comms are lost. Stand-Alone Control is a must, but apparently our Design Mechanical Engineers are missing this when they name RTU products that can be used, but do not meet the Sequences that they themselves laid out.

    JCI NAE's & Niagara framework Controllers are used for IT connection and Transfer of Data for Graphics, Alarms & Trending. If we build a School and we do not Spec an NAE or Niagara Framework Controller, then the System should function correctly without them and this is how JCI & Other Control Contractors should plan to install their Systems, so that all Control and Comm Bus sharing takes place through the DDC/BAS System. Then after that is done, Integrate with any System & transfere Data to Graphics, transfere Alarms & Trnsfere Trend/histories.

    ** Here is another Fun Design Feature that we have been getting in our Schools for the last 7 years that I have been here & that would be the lack of Design to include Makeup Air to Rooms with Exhaust Fans, which then become wasters of Energy, because you can't suck air or smell out of a Bottle. When they are told about this Design problem, they just shrug there shoulders and say that we didn't accept their alternate and then you never hear back from them for a soltion, unless it is the PPrincipals toilet and the seat is freezing when she sits on it. So this one comes up in a meeting and I tell them that they did not undercut the door enough to allow air throughbecause of the size of the threshhold. Their solution is to move the Exhaust grill from the middle of the room to over top of the Toilet & after this was done it still was cold in the Bathroom. So, I bring it up again, but include all the other Restrooms that are typical. They design a $3,500 in the wall Electric Heater directly across from the Toilet, with a Remote to solve the problem.

    Boy, I hope no one goes in there after a nasty smelling Restroom break from someone. They may need to "Sprizzle Their Shizille".

    BigdogTim7
    "Please, Do Not Shoot the Messenger!!!"


    "It is not what you Know, but rather, Knowing where to find the answer when you need it"

  8. #8
    Join Date
    Jul 2012
    Location
    Northern NY
    Posts
    121
    I agree and see these problems in schools all the time from design engineer. As much as I blame them for poor design alot does come down o price. If you want to truly have a standalone system like you describe plan on tripling your control budget (at least) and ban all packaged controls products. You then need to get the construction manager reviewing all submittals to make sure they only approve the correct designs. If the project goes this way be prepared to have very upset mechanical contractors who will like not bid this way even if required by specs. Also hopefully you get a good controls contractor who will know how to design for a true standalone system.

    In the end I find the maintenance team knows what they want and defines it but between the "money folks" and clerk of the works they are given the cheapest option possible so the rest of the money can go to more paint to make parents think the schools look better.

    -Jeremy

  9. #9
    Join Date
    Jun 2006
    Location
    Mount Airy, MD
    Posts
    89

    Lightbulb

    Quote Originally Posted by kc2dnw View Post
    I agree and see these problems in schools all the time from design engineer. As much as I blame them for poor design alot does come down o price. If you want to truly have a standalone system like you describe plan on tripling your control budget (at least) and ban all packaged controls products. You then need to get the construction manager reviewing all submittals to make sure they only approve the correct designs. If the project goes this way be prepared to have very upset mechanical contractors who will like not bid this way even if required by specs. Also hopefully you get a good controls contractor who will know how to design for a true standalone system.

    In the end I find the maintenance team knows what they want and defines it but between the "money folks" and clerk of the works they are given the cheapest option possible so the rest of the money can go to more paint to make parents think the schools look better.

    -Jeremy
    Jeremy,
    Very well said and good advice. I have a background in tridium niagara framework by Honeywell and before that Invensys in Baltimore & it seems that I am the only one here who knows if we are getting scammed or not.

    Obviously, you read what I had to say. Here in the School System, no one wants to read my comments, much less will they understand them, so I being still payed through Facilities HVAC & no Athority, even though moved to head HVAC on Construction projects, must approach everything I bring forth as "In my Opinion".

    This makes your idea of making the C/M review the Submittals is a Great idea & is something that adds to my comments that any C/M we use must have an On-Board HVAC Mechanical Expert.
    "You then need to get the construction manager reviewing all submittals to make sure they only approve the correct designs"

    The good news is that we have gone to Stand-Alone Units that if DX, come with the Compressors and controls all tied in to a Control Board that the Control Contractor sends a 0-10Vdc signal too. Their complaint is that they have no Status to use for their Control for fine tuning or safety interlocks or for the inherent Time Delays.

    I would just love to see the Mech Engineer locate a Night Setback Temp Sensor in the likely coldest space or room in an area served by the RTU, so that it will run at night as needed. This gets missed on every job and no matter who the Engineer of Record is. They actually say to use the Return Air Sensor, which is rediculous.

    Due to these rediculous things, we are now meeting with our Design Mech Engr for a "Lessons Learned" meeting after our Projects are finally complete.

    You are right that the Mechanical Contractors will miss the extra Spec items until they mess up 1 or 2, since we like to reuse good Mech Contractors & Control Contractors.


    Again, Thx for your advice,

    Tim Heinrich
    "Please, Do Not Shoot the Messenger!!!"


    "It is not what you Know, but rather, Knowing where to find the answer when you need it"

  10. #10
    Join Date
    Jul 2007
    Location
    Mount Airy, MD
    Posts
    7,281
    "Due to these rediculous things, we are now meeting with our Design Mech Engr for a "Lessons Learned" meeting after our Projects are finally complete."
    Will the bean counters be there? As previously mentioned in your environment it typically comes down to them as to what your stuck with.

  11. #11
    Join Date
    Jun 2006
    Location
    Mount Airy, MD
    Posts
    89

    Angry The ineptitude of all area's of HVAC, from Design, down to the HVAC Service Tech's.

    Quote Originally Posted by Chris_Worthington View Post
    Will the bean counters be there? As previously mentioned in your environment it typically comes down to them as to what your stuck with.
    Chris,
    A little late on my reply, but as you already know, the Bean Counters will not be there, because they do not understand our HVAC/DDC lingo. So, in order to not look ignorant on Schools that they Spend Millions on, yet HVAC never seems to work & it has come to the point, that they no longer want to hear the Problems from me, because I am finding Design Problems, which they just can't believe.

    It is like the Conspiracy Movies you see, but it really goes on in the County Governments, as well as all other Governments. They Promote those who are ineffective in the Field, but can organize a meeting and talk down to their level, which is obviously not fixing things. They do not want to promote me, because I am an anomaly to them, in that I know so much about the Mechanical side & the Controls side (Both Pneumatic & DDC/BAS), that they just do not want to pull me out of the Worker Bee Pool of workers, because I will then settle in and have authority to make decisions.

    However, I am at the point of not caring anymore & that is sad, but after 7 years of this, this School System is killing my Health & Drive to clean things up, is just going too pot. I have decided to write all over my Dry Erase board of everything I'm doing, because "I'm Damned if I do & Damned if I don't", along with my Job Description I was hired under, which basically just pays me good Money to troubleshoot and send out emails to the write people. If I send them to my Bean Counting Boss, he asks me to go over everything with him, even though neither of us have time for this, if he would read the email himself & put a little trust in me. Instead he confides in our Design Engineers, who are never held accountable & recreate the wheel on every Project & they never meet with us and determine a "Lessons Learned" report for each finished Project. Secondly, They trust the Commissioning Agents who have yet to complete the most important part of what they are paid to do, which is "Performance Verification". If the Cx Agents did PV testing correctly, by building and using Change of Value (COV) Trending/Histories, in place of timed Trend/Histories, they would capture all of the things that I find & report to the HVAC Team, at the finish of each phase of our projects and then we would only find minimal problems.

    So, in Summary; I have decided that I am really not Paid to be a Lead Person or a Leader of anything and that I really have no one to give me work to do, so I will now just go through the motions and let whatever happens, happen & things will go back to the way they were before I came. *"Out of Sight, Out of Mind".

    I have 3 other peers that share my Job Title & none knows anything close to what I do, so I will use my Union to back me, work with Design Teams at the beginning of Projects & just sit there until asked to do something, covered under "Other duties as assigned". You see, the Bean Counters do not realize all the things that I have done & $$$ I have saved them in the 7 years I have had to complete Schools HVAC/DDC/BAS portions of Projects. 1 recent example is that we have just finished a renovation of a School that had a poor original Design with Plenum Return Air. So when we went through the phases, the JCI Tech had asked me to check the Units because the Return Air didn't seem right & the OA dampers being cracked open for a 15% Minimum were tripping the Freeze-Stats. I being Handi-Capped, climbed up to the roof and found the Mixed Air Chamber under an immense Negative Pressure, so I told the Construction Manager to have someone check the Return Grills in The ceilings because I knew they had to be clogged, as I had seen it before in the County & later confirmed at minimum a 75% clog on each Return Grill screen in the ceiling (Facilities said that it was a Custodial Problem & I asked how they would know or where to locate these & they told me that I had to show them) Crazy, Crazy, Crazy!!!. I then found a 1-Kw Heater in each of 8 McQuay RPS Units with the Setpoint turned all the way up on the Warmer side. This was after I received a call because the Mechanical Contractor had to Shock & Flush the Chill Loop & switched the pumps too hand over night. The next morning, The Schools mechanic asked me what I thought caused the Chilled Water loop Temp to be above 120.0 deg F? I had to go to the School and see for my self & easily made the correct analysis, that since the Return loop was higher then the Supply that the Heat was coming from the Building somewhere & not from the Heat generated by the pump, as the Tech thought. This is when I put 2 & 2 together & realized that the Electric Heaters in the Units were on 24/7 in the 8 Units and the Unoccupied Units were now Heat Ex-changers, passing Heat from the Unit, into the Chill Loop. Lucky for the Tech, that he did not start the Chiller and possibly Blow its Charge, which would cost a ton of $$$. I then asked this Tech to go up and turn all 1-Kw Heaters down to minimum, which was original design to keep units from Freezing, but he would never do it after I asked him so many times and even sent a email to our Top Boss regarding the waste of Energy (1,000 watts = a little more than 16 60 watt light bulbs), while imagining not 1, but 8 Homes on a hilltop without blinds and each house having 16 - 60 watt Light bulbs ON 24/7 & you will get the picture of the $$$ wasted for 13 years & there lies our current problem, with the lack of proper training & lack of knowledge on the Basics of HVAC. Result was a kind thank you note from our Boss's Boss, but no request to correct the settings on the Units. After 1 more year and about 15 meetings where I would ask if the Heaters had been turned down? I was told he didn't have time to do it, So, me like a dummy, climbs up to the roof & I turned them down and marked them all with Sharpie.

    I Give up!!! Too much ignorance & hiding what people do not know, instead of realizing their weak area's and getting more training. Also, I get to make enemies because I end up revealing all these ridiculous problems, that should have never happened. Oh Happy day!

    Again, I am a pilgrim, standing on an Island and getting shot with arrows every day!

    Thank God for the guys here on HVAC-Talk.com who have given us a great place to vent.
    "Please, Do Not Shoot the Messenger!!!"


    "It is not what you Know, but rather, Knowing where to find the answer when you need it"

  12. #12
    Join Date
    Jun 2006
    Location
    Mount Airy, MD
    Posts
    89
    Excellent comment jeremy. Thx for your input on this issue.
    Quote Originally Posted by kc2dnw View Post
    I agree and see these problems in schools all the time from design engineer. As much as I blame them for poor design alot does come down o price. If you want to truly have a standalone system like you describe plan on tripling your control budget (at least) and ban all packaged controls products. You then need to get the construction manager reviewing all submittals to make sure they only approve the correct designs. If the project goes this way be prepared to have very upset mechanical contractors who will like not bid this way even if required by specs. Also hopefully you get a good controls contractor who will know how to design for a true standalone system.

    In the end I find the maintenance team knows what they want and defines it but between the "money folks" and clerk of the works they are given the cheapest option possible so the rest of the money can go to more paint to make parents think the schools look better.

    -Jeremy
    "Please, Do Not Shoot the Messenger!!!"


    "It is not what you Know, but rather, Knowing where to find the answer when you need it"

  13. #13
    Join Date
    Feb 2014
    Location
    Dallas, Texas
    Posts
    9
    We are working on hydronic replacements of steam convector systems in schools and threads like this are exactly why I signed onto this board. Great stuff and great 'head up'.

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