Has anybody had problems with the new Trane RTAC chillers? We are having low evap temps on two machines (200) tones each and have had Trane out to help and we are still having issues. We have a computer room that has low load and they have 9 Crack units that are water cooled and to get enough load to keep the machines running at 28% I have put 5 units to cool at 70 and 4 units to heat to 74 and this is helping to get load up since the room is only about 10 tons of load at this time. They are suppost to load up the room up in the next 2 weeks so this is the best I can come up with to increase load for now. I have proven we have plenty of water flow and on a cold night (24 f ) we are going low because of the large coil and causing the evap to go out on low evap temp. I am concerned that the condenser pressure is dropping as it gives up heat and causing this issue so I had our controls guy trend the fla amps today to determine if this is the issue. If you guys have had issues with this I appricate any help you can offer as I am pulling my hair out on this. By the way Trane is no help and I will never reccomend them for replacement because of the lack of help on this issue.
Trane chiller RTAC low refrigerant temp trips
teckster
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The problem with the low charge theory is that we recovered the charge and weighed it back in, and topped it off. It was about 60 lbs short. It is only the second stage that is running low evap temperature and pressure. When we opened the access valve at the bottom of the evaporator, we got liquid out with out any presence of oil.
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Just coz you got refrigerant from the access valve doesnt mean you dont have excess oil. Do you know the history of the chiller??? has it ever had oil added . How are you checking the oil level ?? you need to run the compressor fully UNLOADED to recover oil for at least 2 hours then check it ACCURATELY with a sight glass on the separator to be sure the oil charge is good.
You're going to have to log the chiller, check & make sure your transducers are working. Use a gauge not just the front-end. Log info off techview, include subcooling etc.
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I agree with what was said about checking transducers and temp sensors for accuracy but it almost sounds like a restriction in the liquid line... have you checked/changed drier cores... check pressure drop?
RTAC Low evap temps
The latest formware is 37. BUT---- Please make sure the oil return solenoid is working properly. This will cause a normal level (not refrigerant) in the falling film evap and low evap temps. I have been down this road. Also, water flows are critical.
The latest formware is 37. BUT---- Please make sure the oil return solenoid is working properly. This will cause a normal level (not refrigerant) in the falling film evap and low evap temps. I have been down this road. Also, water flows are critical.
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M100, what did you find because I am getting my butt kicked on an RTAC right now with low trips.
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I well buddy looks like you got a lot of Trane Techs trying to help you, but I guess we are of no use. Looks like you got yourself a problem. I can't tell you to listen to these guys, but they are all correct. You have the info to find the issue. Now look and find it. Low evap temp could be caused by a lot of different scenerios. When you can answer all of the questions above and comeback with some valueable facts then we might have an answer. Until then Ta Ta for Now.
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Ok, I have had this problem on several chillers for different reasons. Two times it was a stuck EXV, There is no feedback from the EXV to the dynaview so if the level in the evap is starving the unit will try to control the exv to open more, but it really doesnt know where that exv posistion is, its timing based. So what if the exv is stuck @ 20% open? One way to check is to shut that circuit down and look & listen, there shouldnt be any refrigerant going through that EXV. Another diagnostic follows this sometimes for high liquid level. Also put the chiller in binding view and manually drive the valve open and closed. Physically go and look in the exv sightglass and see if its really working. The other was a liquid level float problem. Make sure someone didnt accidently pitch the lower float level line back towards the canister, if it is it will vapor lock and give false evap liquid levels. You should be able to test the float while the chiller is running by using techview to monitor the float level and manually closing the liquid line valve and watching the liquid level drop. If playing with the liquid line valve results in no liquid level float change then the float is suspect. Also make sure youre not oil saturated, there is an active oil return on that chiller, on the 3/8 line that terminates on the underneath of the compressor, before the compressor is a strainer. Isolate the strainer and be sure its not plugged. If its plugged, over time the evap will become oil logged or saturated. Evap approach should indicate this.
I have had this problem once with the stuck EXV. But have you checked your transducer?
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It may also pay to make sure the lines to the liquid level float have not been bent or moved as this will affect the readings and cause the EXV to play up.
Problem solved
Turns out it was a bad liquid level sensor. There is a new type Trane switched to. It is an upgrade kit to a digital sensor. We also had to upgrade the software on the CH530 to the latest version in order to recognise it. Unit has been alarm free for a month now. Knock on wood. Thanks for all of your sugestions and assistance.
Turns out it was a bad liquid level sensor. There is a new type Trane switched to. It is an upgrade kit to a digital sensor. We also had to upgrade the software on the CH530 to the latest version in order to recognise it. Unit has been alarm free for a month now. Knock on wood. Thanks for all of your sugestions and assistance.
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It took you nearly a year to fix it ???? Lol
You have one patient customer there
)) ))
You have one patient customer there
)) ))hey bud, i reading this post and was wondering, i am assuming that low oil flow has a simillar alarm of low evep temp. i know if oil filter is plugged or valve may b close will cause a restriction and send an alarm, can u help explain this alittle please, also on the liquid level sensor, does it have an eye or a float with an arm, what could happen if the level gets too low or high?
thanks
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You have to call Trane to get it... I wouldnt ask for touchview software though
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Yep the latest version is called "feelyview" now .
dunno about "touchview but..well, pal see if this helps
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Touchview ... Feelyview ... Krastralview , krestralview , eagleview, vultureview.... They all have their personalities and features .... Take ur pick .
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