TRANE RTHD UB1F capacity problem

[FREONsteve]

I am working on a trane chiller model RTHD UB1F XH0U AC1A BRAL D1A2 RALA VXQA EXAA XXY1 46FG UA5X XXXX DX and have a question about the chiller not loading up to full capacity. It will only run between 70 and 75% of RLA
Now its for a school and they have two of the same chiller. They alternate between the two and never run both at the same time.If I run the other one it will load up to 100% capacity and step down when its closer to set point and maintain it. Now if I run the other one in question it only goes to 70 to 75% RLA. Any reason as to why? I have showed a fault in the history for well over a month and it was a loss of water and thats because the school district killed the pump. If you need any other info to help me out I can provide it hopefully.

Thanks in advanced.

[cperk]

Do they have seperate chilled water pumps? If so have you checked to see if they both have the same flow or pressure drop on evap? Startup screens in strainers? Does it pull temp. when only loaded to 70 or 75%? Oh yeah, what about current limit setpoints?

[klove]

It would be immensely helpful if you'd post the readings with the chiller as loaded as it will get (all of them, including the setpoint). Also, what does the control display say that the current status of the chiller is while this is happening? Are you controlled locally or from a BAS?

[servicetrane]

there is any existing alert? Full refrigerant charge!

[rover]

Two chillers lead/lag I would assume. EXV position should tell the story. Pretty sure these chillers rely on adequate pressure differential to load.

[Healey Nut]

Klove is correct , without readings and more info its a crap shoot .
It could be something a simple as the BAS sending the wrong current limit signal .

[cooolguy]

Chiller requires minimum of 25 PSID Refrigerant is used to move slide valve on water cooled trane chillers. Make sure you are not stacking refrigerant in the condenser verify your tower water setpoint.

[ga1279]

FREONsteve- most school districts use some form of building chiller, pump, boiler and air handler control logic. Most of these have the ability to control temperature set point and current demand limit. You may be showing a 75% current on the CH530 display but that a front panel setting, if the chiller design is lead/lag it may have been set up as the lag chiller. You may have to go through the menus (radio points to check current limits, remote settings etc. etc. and so forth.-GEO

[klove]

It's been 11 days since Steve asked about this issue and it's time that he responds to some of the responses.

[cperk]

Where is stevo?

[milkyway]

stevooo ., its like where is waldo lol