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Originally Posted by KnewYork

I'm not sure I'm following you here. Vanes not opening enough would prevent a chiller from loading to 100%.

If the chiller was short of refrigerant it is possible for it to run and not load to 100%, but the vanes would be wide open because the controls would be telling the machine it still had to load.

That is true, especially if it is not able to get to setpoint - if leaving chill water temp is high enough above setpoint, even with an increase in the approach, the evap temp may not reach the freeze stat setting. A good point, which I failed to consider....

Originally Posted by ZT

Basically:

Vanes not closing enough
and Low refrigerant

cause a chiller to not load to 100% but im sure there is more

I'm not sure I'm following you here. Vanes not opening enough would prevent a chiller from loading to 100%.

If the chiller was short of refrigerant it is possible for it to run and not load to 100%, but the vanes would be wide open because the controls would be telling the machine it still had to load.

All I wanted to know was what symptoms would cause a chiller not to load to its full potential. Don't need help diagnosing it just was curious.

Basically:

Vanes not closing enough
and Low refrigerant

cause a chiller to not load to 100% but im sure there is more

Don't need no stinking readings, Just replace everything and hope that takes care of the problem. It's all about process of elimination. Unfortunately, Elimination of process seems more and more like the new standard.

Originally Posted by Healey Nut

Thats why a set of readings in the post and question helps ...otherwise were all just P#!&&%g in the wind with ideas .

Just remember to stand down wind , might be why you can't split them hairs still.

Originally Posted by jimbob73

Fouled evaporator tubes can also prevent chiller from reaching 100% RLA and leaving water temperature setpoint. With fouled tubes, The evaporator saturated refrigerant temperature and approach will be in normal range on a CVHE/F. With flows at design, The fouled tubes indicator is best seen with the not so good Delta-T. Through me for a loop the 1st time I ran into this when I had a CVHE with a classic panel that wouldn't load up beyond 75-80% and anything that could have caused it on the capacity control side and vane assembly was all good. I'm just glad in this case I didn't upgrade the chiller to adaptiview to find the evaporator tubes being the culprit.

Thats why a set of readings in the post and question helps ...otherwise were all just P#!&&%g in the wind with ideas .

Fouled evaporator tubes can also prevent chiller from reaching 100% RLA and leaving water temperature setpoint. With fouled tubes, The evaporator saturated refrigerant temperature and approach will be in normal range on a CVHE/F. With flows at design, The fouled tubes indicator is best seen with the not so good Delta-T. Through me for a loop the 1st time I ran into this when I had a CVHE with a classic panel that wouldn't load up beyond 75-80% and anything that could have caused it on the capacity control side and vane assembly was all good. I'm just glad in this case I didn't upgrade the chiller to adaptiview to find the evaporator tubes being the culprit.

I guess we are not supposed to put our e-mails in our posts, so I need a mod to please remove mine as I cannot edit posts nor can I send PM's like I used to be able to do :/

Why can't I send PM's?
Why can't I edit my posts in certain forums?
Why are my freedoms being taken away lol?

Probably, but the most obvious indication of the charge being low enough to cause loading problems will be a period of a fully unload signal from the capacity control module. The frequency of that occurring will be affected by how low the charge is and how much the chiller is trying to load. You will see the red light on the panel light continously and the vane operator drive continously to fully unloaded. It is not like later models with "Adaptive" controls. This has a 2 step freeze stat, where the first step initiates that unload signal. When unloaded, evaporator temp rises, that first step resets, chiller begins loading again to setpoint, and the whole process begins again.

Won't low refrigerant (leak) cause it to also not load to 100%?

Yes R123, It hasn't been installed yet.

CV GearDrive my e-mail is DPark017@gmail.com

Originally Posted by ZeroTolerance

Luckily another one of our buildings has a spare control box they are going to put on for the time being. At least until we get our new Trane VFD 800ton Chiller.

If your talking about the black box in the starter, it is calibrated to the specific chiller it came from. You better make sure it had the same RLA.

Hi,
Inside black box there are two connection points. J1 & J2. Usually these are connected with a jumper. If you remove this jumper the unit will not load above 90%. Please check this and if there is no jumper, install one if you know why it is removed.
In calibrated FLA you should receive approximately 8,25VDC in V1-V2. I usually calibrate the Capacity Control Module (CCM) to start current limit condition at 8,07VDC.
I’ll send you a useful service bulleting if you send me your email address, but I don’t believe that the black box is damaged. Maybe current calibrator needs to be readjusted.
If you have 8,25VDC at your 80% then current calibrator need to be recalibrated.
Regards,
CV

Exactly what box are we talking about? If it's the one in the starter, there could be a critical adjustment that needs to be made.

Luckily another one of our buildings has a spare control box they are going to put on for the time being. At least until we get our new Trane VFD 800ton Chiller.

I was actually thinking of the solid state overload in the starter for this chiller. I was wondering why I was the only one standing at the starter, while the rest of ya"ll are at the control panel! Not all Trane techs will be familiar with troubleshooting this model. I suspect many newer ones may not be familiar with the special tools required. I know some aren't even aware they exist (the tools, that is).

Originally Posted by Healey Nut

...If its the Black Box Im thinking...

that was the one that I was thinking about...V1 and V2!

Yep thats the one mid 80s Classic Black panel . All obsolete non available parts .
It could be that the current limit potentiometer is dirty , it could be short of gas , the low evap temp control needs calibrating etc etc .
You question is way to vague to answer without a full set of accurate readings and even then its a crap shoot .
you need an experienced Trane tech who is familiar with the older control panels and the black box in the starter to tell you whats wrong with it .

Seriously, this thing is old. It is a base building chiller and the building was built in 1984. The current is set at 100%. It hogs power like a SOB. We are going to eventually replace it in the next year with a new VFD Trane 800ton. Just curious as to what would cause it to only run at 80%

All I know is that it has four big vertical gauges on the far left front of the black box, about 8 vertical incandescent lights next to the gauges with white levered breakers next to them, and the current and chilled water control is a potentiometer with knobs lol. It is as old as I am.

Yes healy, I believe you are talking about the one I am.

Originally Posted by emcontrols

Ouch!!!!!!!!!!!!!!!!!!! (Black box UCP1) The retrofit kit might be half the cost of a chiller been there and done that last summer.

Black Boxes are before UCP1
If its the Black Box Im thinking off then your SOL they are obsolete long time since . Unless you know a very freindly Trane tech who kept one in his garage and has the TOL 90 to set the current calibrator .
Is it a Classic Black panel with the gauges on the left hand side vertically .
Time for a controls upgrade and get your wallet out and be ready for a big bill .