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  1. #1
    Join Date
    Aug 2006
    Location
    ohio
    Posts
    251

    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
    Join Date
    Feb 2012
    Location
    EVERYWHERE
    Posts
    197
    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
    Join Date
    Feb 2012
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    EVERYWHERE
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    Your approach is high what is your entering and leaving water temps?

  4. #4
    Join Date
    Aug 2006
    Location
    Mixing oil and fire with a big spoon.
    Posts
    4,007
    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.
    It's tube brushing season...93% done (39.35 miles of tubing)...only 1,242 tubes to go!

    Original member of the Raccoon Brotherhood.

    EVERYTHING IS AWESOME!!!

  5. #5
    Join Date
    Feb 2012
    Location
    EVERYWHERE
    Posts
    197
    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
    Join Date
    Jul 2007
    Location
    The Hot South
    Posts
    1,204
    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
    Posts
    1,847
    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
    Join Date
    Aug 2006
    Location
    ohio
    Posts
    251
    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.

  9. #9
    Join Date
    Mar 2004
    Location
    ottawa canada
    Posts
    1,847
    I removed 3 gallons of oil so I put three gallons of oil in even though the nameplate says 2.1 gallons.

    Houston ......we have a problem . The nameplate gives you those details for a very good reason .
    Would you put 8 Quarts in your car if the nameplate said 5.5 was enough .....sure just go ahead add a bit more just to be on the safe side after all its only a bit of extra oil ...no big deal right ????? WRONG !!!!!!!!!!!
    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 .

  10. #10
    Join Date
    Jan 2011
    Location
    tt, west indies
    Posts
    125
    Did you confirm these readings by a manual gauge?. What worries me is that u said u added 30# and unit didn't cut off on higgins pressure. And 3riple corendrier , why don't you try locking out the circuit that is presently work good and run the other circuit by itself , the water temp is @ 42 degf so it will not need 2 compressors to run. At full load to come down lower

  11. #11
    Join Date
    Jan 2011
    Location
    tt, west indies
    Posts
    125
    The other thing is you must maintain correct oil level in those compressors or you will have a high oil temp problem ,btw what is the oil temp? On system when it's running?

  12. #12
    Join Date
    Jul 2007
    Location
    The Hot South
    Posts
    1,204
    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

  13. #13
    Join Date
    Jul 2007
    Location
    The Hot South
    Posts
    1,204
    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.

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