When you say "no water at far end" I am not sure what you mean. Is this a multistory building, or all on one or two floors? If this is a multistory building and you mean "far end" by the bottom, then the coils at the bottom my have collected debris and may need to be flushed. If this is building all on one floor then air may be trapped in the coils or both.
In any case do these cooling coils have air bleeders on them. They may have air trapped in them. If this is the case you will have no or very little flow. The air must be allowed to come out. Do you have air bleeders on each coil? if so , have they been bled?
Each cooling coil should also have a drain for flushing. This could be used for bleeding air as mentioned or used for flushing debris. Have the coils been flushed to ensure there is no debris? New systems are prone to having debris due to slag from welding or soldering.
Each coil should also have two isolation valves. By closing each one, (one at a time) you can flush debris or air.
With the building only retrofitted 10 years ago, you should have drawings from the engineering. Each of the chilled water coils should have been balanced. The balancing valve should be on the return water side. There should be a balancing report. If not you can contact a balancer to look at the system. All the coils will need to be checked one at a time.
Do you have a chemical treatment company? if not you should contact one to help you analyze the the chilled water. If you have not been treating the water and some of your chilled water piping is steel, you will have a problem as steel needs to have treatment in order to keep the reaction of corrosion in check. Debris from corroding inner piping will cause your water to become black and full of debris. It could get black and thick. I have seen this.
You should have a micron filter installed on your chilled water loop. A chemical treatment company will help you find the best place to install this. Usually hooked to the supply and return piping on ether side of the chilled water pump. The filter should be checked and replaced when needed.
If you do not have any steel piping debris can still be plugging your system in spots and require flushing. 30 units is not that many so flushing the entire system should not be a problem. Again a chemical treatment company can help you with this.
Controls, are the control valves opening and closing properly?
What kind of controls do you have? pneumatic or electric? have they been checked for proper operation? If pneumatic do you have proper air pressure all they way through your system? Do you have an air dryer on your pneumatic system? if not you could have water trapped in your pneumatic system causing your controls to not function. Electric valves could not be receiving a signal and be operating intermittently. Have your controls person check these.
Control valves for the main chilled water system, do you have any? are they working properly?
I would assume you should have tried most of these options before changing a pump or a chiller. They would be the last things to change.
Hope some of this helps
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