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  1. #1
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    ohio
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    Rtac loading problem-new compressor trane

    Rtac2504. Compressor was bad. Changed out, standard procedure. Started up today, when starts perfect just as it should, and runs at about 45%. Within a few minutes it will start to load as it should, and loads to approximately 80%. As soon as it gets loaded it starts unloading slowly and it never will load again no matter what the demand is even 10+ degrees off of setpoint. After it unloads completly I can jump out 1u21 terminals and manually load it but it will try continuously to unload. At 80%
    cond press 165
    sat cond temp 117
    evap press 38
    sat evap temp 43
    approach temp 14
    liq. level -.7
    When it unloads to 56% numbers are as follows in same order
    109
    92
    31
    35
    7.7
    -.8
    Is there a factor that I am not seeing that will cause this to unload. I did change out liq line filter with a 3 core drier shell and added 10# to compensate for shell. Sightglass does have flashing and all fans were running it was 75 degrees today in ohio and I had a good load on the chiller. I even added additional 30# trying to clear the glass but it would still flash at times. And I recovered the additional 30 when it didnt make a difference. What does this look at to load/unload? Does anyone have any literature on this machine other than the iom? I am not very familiar with the rtac control scenario and it is obviously very different than the rtaa. condenser is very clean also, thanks in advance mike

  2. #2
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    You do not clear the sight glass on a RTAC. You charge by subcooling. The compressor loads and unloads based off a algorithm in the controls.

  3. #3
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    Your approach is high what is your entering and leaving water temps?

  4. #4
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    Mixing oil and fire with a big spoon.
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    Quote Originally Posted by michael26 View Post
    ...At 80%
    cond press 165
    sat cond temp 117
    evap press 38
    sat evap temp 43
    approach temp 14
    liq. level -.7
    When it unloads to 56% numbers are as follows in same order
    109
    92
    31
    35
    7.7
    -.8...
    Focus danielson.
    "Mother" is the name for God on the lips and hearts of children....The Crow

  5. #5
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    I was not wanting to do any math and still don't know entering temp. Also if the transducers and water temp sensors are right he has a 42.7 leaving water temp at 56% loaded. So if your entering Is high could be low water flow and dirty tube.

  6. #6
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    Jul 2007
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    Your missing a lot of data here. What is your entering and leaving water temps? What is EXV position at full load? What is your subcooling? What is oil temperature vs saturated cond temp? What limit is the controller showing when it won't load up? How much extra oil did you add to the circuit which is probably contributing to this problem? What is the oil level? Why did you alter the design of the chiller by adding a 3 drier shell to the liquid line instead of following the manufactures recommended cleanup procedure? What do you mean by "standard procedure"? Do you have the older style chiller barrell with the external liquid vapor seperators on top or do you have the newer style RTAC+ with the internal liquid vapor seperator (if you don't know, this can be determined by serial #)? What software version are you running? Are you connecting to the chiller with a laptop running TechView?

  7. #7
    Join Date
    Mar 2004
    Location
    ottawa canada
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    2,042
    Quote Originally Posted by R123 View Post
    Your missing a lot of data here. What is your entering and leaving water temps? What is EXV position at full load? What is your subcooling? What is oil temperature vs saturated cond temp? What limit is the controller showing when it won't load up? How much extra oil did you add to the circuit which is probably contributing to this problem? What is the oil level? Why did you alter the design of the chiller by adding a 3 drier shell to the liquid line instead of following the manufactures recommended cleanup procedure? What do you mean by "standard procedure"? Do you have the older style chiller barrell with the external liquid vapor seperators on top or do you have the newer style RTAC+ with the internal liquid vapor seperator (if you don't know, this can be determined by serial #)? What software version are you running? Are you connecting to the chiller with a laptop running TechView?
    Aaaahhhhhhhh Take a breath R123 or were gonna have to call the Paramedics ..................lol. But seriously he is right ..
    And he did miss one very important thing Whats your Delta P across the barrell using ONE gauge !!!!!!!!
    The 64 roars to life Whoo hoo ...shes a rolling chassis .
    You bend em" I"ll mend em" !!!!!!!
    I"m not a service tech.. I"m a thermodynamic transfer analyst & strategic system sustainability specialist
    Best Austin Healey In Show twice in 2013 .....All those hrs paid off .

  8. #8
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    Quote Originally Posted by Healey Nut View Post
    Aaaahhhhhhhh Take a breath R123 or were gonna have to call the Paramedics ..................lol. But seriously he is right ..
    And he did miss one very important thing Whats your Delta P across the barrell using ONE gauge !!!!!!!!
    I think I'm suffering from shortness of breath..............LOL

  9. #9
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    Location
    ohio
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    Quote Originally Posted by R123 View Post
    Your missing a lot of data here. What is your entering and leaving water temps? What is EXV position at full load? What is your subcooling? What is oil temperature vs saturated cond temp? What limit is the controller showing when it won't load up? How much extra oil did you add to the circuit which is probably contributing to this problem? What is the oil level? Why did you alter the design of the chiller by adding a 3 drier shell to the liquid line instead of following the manufactures recommended cleanup procedure? What do you mean by "standard procedure"? Do you have the older style chiller barrell with the external liquid vapor seperators on top or do you have the newer style RTAC+ with the internal liquid vapor seperator (if you don't know, this can be determined by serial #)? What software version are you running? Are you connecting to the chiller with a laptop running TechView?
    You picked up alot of things that I missed. Did not check the subcooling with a thermometer but I know there was 10+ degrees. I did not have my computer with me and that was probably part of the problem I know. I dont know the software version number but I updated it in 2010, the chiller is a 2007 model. My service manager told me the cleanup was adding a 3 core drier, that is why I did it that way. I removed 3 gallons of oil so I put three gallons of oil in even though the nameplate says 2.1 gallons. And I did not wait for the oil heater to warm the seperator before I started, only 2 hours. The entering water temp when I first started the circuit was 50 with a setpoint of 42 and only climbed from there. when I ran the other circuit it would load up and run fine so I would have to believe the problem is with the circuit and not the chiller. The oil temp was the same as the 1st circuit when I ran it for an hour to compare. When I said standard procedure I recovered refrigerant, installed new compressor, added oil, evacuated to 500 microns and held for 5+min. then charged with new 134. replaced contactors that were burnt up I believe it was 1k5,6,7. Also what is the line that goes from the bottom of evap to bottom of compressor? Is this to return oil laying in the evap? again thanks for the help, it sounds like you have done this a few times.

  10. #10
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    Quote Originally Posted by michael26 View Post
    You picked up alot of things that I missed. Did not check the subcooling with a thermometer but I know there was 10+ degrees. I did not have my computer with me and that was probably part of the problem I know. I dont know the software version number but I updated it in 2010, the chiller is a 2007 model. My service manager told me the cleanup was adding a 3 core drier, that is why I did it that way. I removed 3 gallons of oil so I put three gallons of oil in even though the nameplate says 2.1 gallons. And I did not wait for the oil heater to warm the seperator before I started, only 2 hours. The entering water temp when I first started the circuit was 50 with a setpoint of 42 and only climbed from there. when I ran the other circuit it would load up and run fine so I would have to believe the problem is with the circuit and not the chiller. The oil temp was the same as the 1st circuit when I ran it for an hour to compare. When I said standard procedure I recovered refrigerant, installed new compressor, added oil, evacuated to 500 microns and held for 5+min. then charged with new 134. replaced contactors that were burnt up I believe it was 1k5,6,7. Also what is the line that goes from the bottom of evap to bottom of compressor? Is this to return oil laying in the evap? again thanks for the help, it sounds like you have done this a few times.
    If you apply for Pro Membership, we can talk about this in the closed chiller forum.
    Last edited by R123; 09-15-2012 at 03:32 PM.

  11. #11
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    Location
    ohio
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    ok r123 let me try this. Sorry I was just trying to get some info because I don't have anything on this chiller. thanks in advance.

  12. #12
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    ohio
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    I will connect with techview in the morning and check and see what the eev position is. Could the extra gallon of oil be enough to coat the tubes in the evaporator and cause the high approach temp? If so will I be able to bring it back running it fully loaded for an hour or will I need to drain it off the bottom of evap? Also is there a tap in tech view that will let me load it manually, it has been awhile?

  13. #13
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    Quote Originally Posted by michael26 View Post
    ok r123 let me try this. Sorry I was just trying to get some info because I don't have anything on this chiller. thanks in advance.
    Also, you should enable private messaging in your settings.......

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