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  1. #27
    Join Date
    Mar 2004
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    ottawa canada
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    2,081
    Maybe when the operator finally discovered that you can't free cool with these chillers he put it back in mechanical cooling with the cond water way too cold and created the problem.


    I doubt it , it would trip on low differential pressure first .
    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 .

  2. #28
    Join Date
    Jan 2010
    Location
    In a Pineapple Under the Sea
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    149
    Quote Originally Posted by graham View Post
    Maybe when the operator finally discovered that you can't free cool with these chillers he put it back in mechanical cooling with the cond water way too cold and created the problem.


    I doubt it , it would trip on low differential pressure first .
    Thats true.

  3. #29
    Join Date
    Dec 2009
    Location
    Ontario , Canada .
    Posts
    95
    Thank you graham and Dosen'tPhaseMe for your continued interest . I suspect at this time that the chiller is not failing because of the operators experimenting with free cooling . It did however cause me concern . I was worried about migration . However , I had an opportunity to inspect the machine again to day . What I did notice was the pressure at the inlet port of the oil return filter from the gas pump . When the solenoid for the high pressure side energized , all i could see was a 5 psig difference between before and after the event . The Machine was at 90% , discharge pressure was at 136 psig . Low side pressure was 35 at the inlet port of the oil return filter . If the check valve was working correctly and the solenoids were sealing tight , I should see a higher pressure at the inlet port of the oil return filter . 5 psig delta P in my opinion, is not enough pressure to pass the oil and refrigerant mixture through the filter . In my opinion i am losing 95 psig somewhere else . I suspect the check valve or the solenoids at this time .

  4. #30
    Join Date
    Jan 2010
    Location
    In a Pineapple Under the Sea
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    149
    No problem, don't forget about the extra 2 gallons of oil you added. You should check the oil level according to instructions in the IOM amd remove any excess. I would keep checking this peroidically until you get the 2 gallons out and your oil level stabilizes at the recommended level.

  5. #31
    Join Date
    Dec 2009
    Location
    Ontario , Canada .
    Posts
    95
    Quote Originally Posted by Doesn'tPhaseMe View Post
    No problem, don't forget about the extra 2 gallons of oil you added. You should check the oil level according to instructions in the IOM amd remove any excess. I would keep checking this peroidically until you get the 2 gallons out and your oil level stabilizes at the recommended level.
    What should the pressure be at the inlet port of the oil return filter with the hot gas solenoid energized .

  6. #32
    Join Date
    Dec 2009
    Location
    Ontario , Canada .
    Posts
    95
    Quote Originally Posted by graham View Post
    What has the liquid level sensor got to do with oil return ???
    The oil charge is much more critical than the refrigerant charge ,if you weighed it in then you should be ok . But just guessing at the oil level and adding oil without accurately checking the oil level in the sump is asking for trouble . Has someone closed the oil sump vent valve by mistake ??
    Checking the oil level with a standard refrigerant sight glass is a PITA . I have a 10" long glass which gives an accurate reading every time no fooling around up and down with the glass .
    Without techview and the ability to use it properly to troubleshoot all the oil system components your flying by the seat of your pants on this one .
    Does anyone have a part number and distributer for the oil level gage ?


    Regards

  7. #33
    Join Date
    Mar 2004
    Location
    ottawa canada
    Posts
    2,081
    Heres the link . I dont know of where you can buy them . I was given one by a customer I helped out of a jam one very hot summer
    .http://www.ldi-industries.com/013277.htm
    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. #34
    Join Date
    Jan 2010
    Location
    In a Pineapple Under the Sea
    Posts
    149
    Thats a good idea, using liquid line sight glasses is a pita. Try hear, they have a pretty good selection. Also there is a sight tube at the bottom of page 528 but is a little pricey. That would be great for measuring the liquid level on low pressure recovery tanks until the r123 eats it away.
    http://www.mcmaster.com/#liquid-level-gauges/=6ctww1

  9. #35
    Join Date
    Nov 2009
    Location
    USA
    Posts
    26
    I work for Trane and have spent many hours on RTHD chillers, usually oil loss problems.
    1. Insure the gas pump is working properly. There is a gas pump check out procedure, but I'm in the field and can send it.
    2. DO NOT add anymore oil.
    3. Once the gas pump is working properly, run the chiller UNLOADED for 30-45 min, shut down - check oil levle (if good) drain 1 gal. Run UNLOADED for another 30-45 min, shut down and drain the last gallon.
    4. You should have the good refrigerant level sensor if this is a RTHD chiller.

    Almost all oil loss problems are gas-pump related. I have had the check valve not seat, and I have the high side solenoid valve port become obstructed. The check valve was an issue with the RTHC, but a new design was installed which is on the RTHD which were improved.

  10. #36
    Join Date
    Dec 2009
    Location
    Ontario , Canada .
    Posts
    95
    Quote Originally Posted by scott_RWS48 View Post
    I work for Trane and have spent many hours on RTHD chillers, usually oil loss problems.
    1. Insure the gas pump is working properly. There is a gas pump check out procedure, but I'm in the field and can send it.
    2. DO NOT add anymore oil.
    3. Once the gas pump is working properly, run the chiller UNLOADED for 30-45 min, shut down - check oil levle (if good) drain 1 gal. Run UNLOADED for another 30-45 min, shut down and drain the last gallon.
    4. You should have the good refrigerant level sensor if this is a RTHD chiller.

    Almost all oil loss problems are gas-pump related. I have had the check valve not seat, and I have the high side solenoid valve port become obstructed. The check valve was an issue with the RTHC, but a new design was installed which is on the RTHD which were improved.
    I do suspect the gas pump . The high side solenoid does not have good temperature gradients when energized and the check valve is a mystery , sounds like its working but how well ? The biggest problem for me is that the pressure at the inlet of the oil return filter is only 5 psig delta p when the high side solenoid is energized , at 90% load with discharge pressure at 136 and suction at 35 psig respectfully . I don't have a base line for this pressure under normal operating conditions . In my opinion the pressure at the inlet of the oil return filter is indicative as to how well the gas pump is working .

  11. #37
    Join Date
    Dec 2009
    Location
    Ontario , Canada .
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    95
    Quote Originally Posted by Doesn'tPhaseMe View Post
    Thats a good idea, using liquid line sight glasses is a pita. Try hear, they have a pretty good selection. Also there is a sight tube at the bottom of page 528 but is a little pricey. That would be great for measuring the liquid level on low pressure recovery tanks until the r123 eats it away.
    http://www.mcmaster.com/#liquid-level-gauges/=6ctww1
    Thanks Doesn'tPhaseMe . That was my first choice . But I first had to prove to the service manager the Buna-N was POE and R134A compatible for this application . Its a little difficult working the tools and administrating at the same time LOL . Its on order as we speak .

  12. #38
    Join Date
    Nov 2009
    Location
    USA
    Posts
    26
    When the gas pump is on a drain cycle you need to listen carefully to hear if the tank empties. It is difficult but can be done. It will change sound to like a hissing noise when empty. It should not hiss too quickly because this would indicate the tank doesn't have anything in it in the first place.

  13. #39
    Join Date
    Dec 2004
    Location
    Brooklyn, New York
    Posts
    170
    Dont know if this helps-but that float in the gas pump was originally some type of plastic ball (or other tyoe of material), but we had similar issue, and after cutting open a gas pump we found that little ball had melted or warped from the heat of brazin all the line goin into gas pump. I cant remembr if that was on an rthc or rthd? hmmm. I'll have to ask.

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