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  1. #14
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    Quote Originally Posted by MaxBurn View Post
    The direction I was heading was let's say each tower is sized for a 800 ton chiller and your overall plant load is only 300 tons or less in the winter so you are only needing one tower and you do need the bypass valve to keep the CW temp from getting to low when OAT is in the 40°s.
    Continuing from the hint the towers are "supposed" to be able to rotate from a primary and two secondary's on a schedule and on faults. The issue with that theory is that the tower bypass valve which is necessary for light loads in cold weather to keep CW temps up is piped INSIDE tower 3's isolation valves. As soon as you close those 12" motorized isolation valves to move away from tower 3 you lose the ability to use the bypass valve and lose control of CW temps.

    RFI to engineer asking about above results in making tower 3 "primary" at all times, no rotation. Just ignored the fail over issue. Refused to admit anything as this will obviously be some money to correct.

    Bonus #1: customer started complaining first winter about tower 1 and 2 turning into swamp land because they never get used. Controls can't do a thing about it guys.

    Bonus #2; there was a commissioning agent involved with this job too. IMO if they did their job they would have pushed this before it was built but as typical they showed up last month and can't do a thing either.
    Scott Jalbert, WebCTRL ninja, Naiagara AX and Smartstruxure newb, SiteScan Retired

    The master has failed more times than the beginner has even tried

  2. #15
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    In the good old days it was typical for equipment to be shut down or valved off based on required loads. Automated controls just hadn’t come along yet.

    Is it possible for plant personnel to valve off and drain CT1 when weather gets cooler?
    It's an upside down world we live in.

  3. #16
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    Quote Originally Posted by David Goodman View Post
    In the good old days it was typical for equipment to be shut down or valved off based on required loads. Automated controls just hadn’t come along yet.

    Is it possible for plant personnel to valve off and drain CT1 when weather gets cooler?
    Tower 1 and 2 are standing by in case 3 fails in this scenario. We do have provisions in place where you can mark one of those out of service and then they are free to drain it. Then "only" one tower will turn into a swamp I guess. I wouldn't recommend they drain both 1 and 2.
    Scott Jalbert, WebCTRL ninja, Naiagara AX and Smartstruxure newb, SiteScan Retired

    The master has failed more times than the beginner has even tried

  4. #17
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    Does that mean I win the booby prize with my post #10?
    If you were a real tech, you'd solder a relay on that board and call it good to go.

    I do a triple evac with nitro to remove non condensables.

    I use 56% silver on everything except steel.

  5. #18
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    Quote Originally Posted by BBeerme View Post
    Does that mean I win the booby prize with my post #10?
    Yes you do! I totally missed that, sorry!
    Scott Jalbert, WebCTRL ninja, Naiagara AX and Smartstruxure newb, SiteScan Retired

    The master has failed more times than the beginner has even tried

  6. #19
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    Bonus Round. This one is a little more obvious.

    Name:  chillers.jpg
Views: 209
Size:  38.9 KB
    Scott Jalbert, WebCTRL ninja, Naiagara AX and Smartstruxure newb, SiteScan Retired

    The master has failed more times than the beginner has even tried

  7. #20
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    Probably something to do with the aux condenser, because if CH-1 goes down, you got nothin' for that.
    If you were a real tech, you'd solder a relay on that board and call it good to go.

    I do a triple evac with nitro to remove non condensables.

    I use 56% silver on everything except steel.

  8. #21
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    Yeah, again RFI came back make that chiller primary. Only thing is it turns out these chillers do NOT like to sit unused for a couple months, multiple faults (I think oil related) if you try to switch to one after that. Trane tech said rotate weekly so that's what we did, no problems with the chillers after that. Just don't get the DHW preheat benefit but a third of the time now.

  9. #22
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    Let me get this straight, the two schematics you've posted were drawn by engineers with little to no field experience. And the customers got the engineering they paid for? Right?
    If you were a real tech, you'd solder a relay on that board and call it good to go.

    I do a triple evac with nitro to remove non condensables.

    I use 56% silver on everything except steel.

  10. #23
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    So, the auxiliary condenser isn't a condenser at all? Just a heat exchanger, but no change of state? LOL
    If you were a real tech, you'd solder a relay on that board and call it good to go.

    I do a triple evac with nitro to remove non condensables.

    I use 56% silver on everything except steel.

  11. #24
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    No idea on their experience level. But it gets better. There was one other large mess up on this job but I have no diagrams for it.

    The new plant is a primary variable plant, only three huge building CHW pumps are supposed to be in the entire CHW system. Except for the pumps that got forgotten about on the back wing in what was originally part of the secondary loop. The original plant was a primary-secondary system and these just got overlooked. That means there was a bypass pipe for the "primary" loop past that secondary loop. The whole primary variable plant did NOT like having a huge bypass out in the field. We could not build pressure even with multiple pumps in the new plant running flat out. Air handlers at the end of other wings weren't getting water and lost control. Took us a while to figure that out but the engineer had the drawings for the original plant and building so I'm thinking no excuse.

    That was a huge change order because shutting the hospital down wasn't going to happen. They had to come in, liquid nitrogen freeze the bypass pipe in two places and cut in a valve to shut that bypass off. It's just impressive that can be done.

    In the end they are still constructing a large bed tower which should add a big heat load. Hopefully that will mitigate some of the rotation troubles as total load will require two and sometimes all three chillers.


    Still more: none of the air handlers have energy valves. Not even pressure independent valves. We can't push these hard enough because frankly the delta temperature in the plant sucks. Unfortunately the customer is not interested in spending that money, even if the payback would be under five years (a guess). But hey, while you are here can you tune this air handlers CHW valve PID, it's hunting all over the place and we are concerned it's going to prematurely wear out this actuator.

  12. #25
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    Quote Originally Posted by BBeerme View Post
    So, the auxiliary condenser isn't a condenser at all? Just a heat exchanger, but no change of state? LOL
    I think it's just a heat exchanger inside the condenser, the water is separated from the tower water. It isn't required to run the chiller. What I don't get is why there is another heat exchanger outside of the chiller? Next fun thing on that loop is there is no expansion tank, all hard pipe and two heat exchangers basically. Don't know what type of pressures happen in there but nothings exploded yet so maybe I don't know what I'm talking about there.

  13. #26
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    The way it is drawn, the auxiliary condenser is a separate component. What I think you explained, is that is actually built into the Chiller/Tower (?).

    The devil is in the details. For example, does CWR mean cooling water return, or chilled water return. Either way, the schematic is not clear what that auxiliary condenser is doing. Other details on the prints may give the full picture. Remember, you're only giving us a small snapshot of the big picture.


    Quote Originally Posted by MaxBurn View Post
    I think it's just a heat exchanger inside the condenser, the water is separated from the tower water. It isn't required to run the chiller. What I don't get is why there is another heat exchanger outside of the chiller? Next fun thing on that loop is there is no expansion tank, all hard pipe and two heat exchangers basically. Don't know what type of pressures happen in there but nothings exploded yet so maybe I don't know what I'm talking about there.
    If you were a real tech, you'd solder a relay on that board and call it good to go.

    I do a triple evac with nitro to remove non condensables.

    I use 56% silver on everything except steel.

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