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Thread: To hot to run!

  1. #1
    Join Date
    Aug 2008
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    322

    To hot to run!

    The college where I work has a 80 ton air cooled trane chiller that is on the science building with 100% outside air. [no return] The problem I am having is this machine will not run in this 108-110 tempture I have been running it at sundown till about 12 noon when it goes down on oil high temp which is above 170 degrees . All fans are running the coils are clean . I have been told that this is all it is going to do due to 100% outside air . My question is anybody got any ideas ? By the way I am located in southern Oklahoma.

  2. #2
    Join Date
    Dec 2010
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    Down by the river
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    I am gussing RTAA chiller? have you used a pressure washer on the coils? I have had them so impacted I had 2 guys 1 crawled inside and 1 out to flush the coils. what were some of your readings, did you check H2O flow?
    It's hard to stop a Trane. but I have made one helluva living keeping them going.

  3. #3
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    Aug 2008
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    Quote Originally Posted by Southern Mech View Post
    I am gussing RTAA chiller? have you used a pressure washer on the coils? I have had them so impacted I had 2 guys 1 crawled inside and 1 out to flush the coils. what were some of your readings, did you check H2O flow?
    I will have to get back with you on all the information.

  4. #4
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    Dec 2009
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    IF it is an RTAA they are good up to 115*F inlet air. Have you actually checked your inlet air temp? Also what is your discharge pressure/temperature? If your pulling 100+*F air through your chilled coil its going to drive your discharge up as well so do you have a design issue? Check water flow and air flow across coil and barrel. Give us some numbers and design specs.

  5. #5
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    Quote Originally Posted by mike robinson View Post
    I will have to get back with you on all the information.
    if you are going back to the job, please take a gas pressure washer with you, and some coil cleaner, stay 10'' from coil make the spray be vertical with the fins and go slow. with someone on top looking down through the fans should see the water comming through the coil, if not youll see the dirt running out.
    It's hard to stop a Trane. but I have made one helluva living keeping them going.

  6. #6
    I've got the same problem going on with a RTAA. Its located close to the building and it's recirculating the leaving air. With the higher than normal temps here it shuts down on the high oil temp and high pressure on the really hot days (100+)

  7. #7
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    Quote Originally Posted by Southern Mech View Post
    if you are going back to the job, please take a gas pressure washer with you, and some coil cleaner, stay 10'' from coil make the spray be vertical with the fins and go slow. with someone on top looking down through the fans should see the water comming through the coil, if not youll see the dirt running out.
    Goodway machines are nice if you have one but if you don't have that, you can make a wand to hook to your water hose to give you great pressure. Take 3/4" copper, ball valve, 1/2 copper, 3/8 copper and adapters to hook to the garden hose. Put a cap on the end and drill 3 or 4 small holes (1/8 ") in the cap and you would be surprised how well you and someone on the other side of the coil can do. Saturate both sides then chemically clean.

  8. #8
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    Aug 2008
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    Quote Originally Posted by Southern Mech View Post
    if you are going back to the job, please take a gas pressure washer with you, and some coil cleaner, stay 10'' from coil make the spray be vertical with the fins and go slow. with someone on top looking down through the fans should see the water comming through the coil, if not youll see the dirt running out.
    Southern Mech don't run off it willbe Monday evening before I can get back with the information. I am trying to take the weekend off I got to have a break been going like a bat out of hell since the last of May with no end in site on top of that school starts in one week.

  9. #9
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    Jun 2010
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    U.A. (upper Alabama)
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    If worse comes to worst put a water sprinkler on each side to keep it online. I have never used a pressure washer to clean an RTAA coil. We always use a firehose, and open the nozzle up where it is more volume than pressure so you don't bend the fins. I bet if I used a pressure washer the coil would look like a smooth block of aluminum.

  10. #10
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    Quote Originally Posted by cperk View Post
    If worse comes to worst put a water sprinkler on each side to keep it online. I have never used a pressure washer to clean an RTAA coil. We always use a firehose, and open the nozzle up where it is more volume than pressure so you don't bend the fins. I bet if I used a pressure washer the coil would look like a smooth block of aluminum.
    I have 4 - RTAA's and 15- RTAC chillers under contract, I clean coils every other month. with a pressure washer. not saying it wont bend the fins, you can't be stupid about it either.
    It's hard to stop a Trane. but I have made one helluva living keeping them going.

  11. #11
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    Mar 2011
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    Abilene Tx
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    Quote Originally Posted by 929rc51 View Post
    IF it is an RTAA they are good up to 115*F inlet air. Have you actually checked your inlet air temp? Also what is your discharge pressure/temperature? If your pulling 100+*F air through your chilled coil its going to drive your discharge up as well so do you have a design issue? Check water flow and air flow across coil and barrel. Give us some numbers and design specs.
    Yeah he's right about the RTAA design temp. I don't believe this heat is too much for the RTAA chillers. I am in Texas and we have had 105+ for many days. I can't even keep up with the days in a row we have had over 100. I work on a military base and we have many of these chillers around. They have been running fine. I have one now that is going off on oil temp. Condensers are clean and all fans running, but have a bad oil temp sensor. If the chiller has the proper clearance, then I wouldn't think it is because of the heat. More than likely you have another problem.

  12. #12
    Join Date
    Jul 2007
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    The Hot South
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    1,310

    Exclamation

    Quote Originally Posted by cperk View Post
    If worse comes to worst put a water sprinkler on each side to keep it online. I have never used a pressure washer to clean an RTAA coil. We always use a firehose, and open the nozzle up where it is more volume than pressure so you don't bend the fins. I bet if I used a pressure washer the coil would look like a smooth block of aluminum.
    Don't put a water sprinkler on the coils unless you are planning on replacing the coils anyway and you are trying to keep the chiller online until the new coils come in. Putting a sprinkler on will load the coils up with calcium and ruin them.

  13. #13
    Join Date
    Jun 2010
    Location
    Tampa, FL
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    101
    May be another problem. Check for cond. air side issues if coils are clean. Too much chemical cleaning can degrade heat transfer. Look for fins flaking off. Check design specs. If chiller holds setpoint it may still be overloaded. Full load amps OK? May have to reduce load on chw side by reducing OA or flow through chiller. If unit is on a roof maybe sprinkler roof surface around chiller without getting chiller wet.

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