Chilled Water HVAC System

It will make a difference. It depends on whether the loss of performance can be accommodated. It is not possible to quantify this loss from here.

The specs of the FCU is:

1. Air entering the coil 80FBD50% RH
2. Air leaving the coil 55FDB54FWB
3. Ch.Water entering 45F
4. Ch.Water leaving 55F

The unit has been selected to neck to neck capacity to the room load and coil capacity. It simply has no allowance to tollarate any reductions in its capacity.

The OEM who supplied the FCU with wrongly labled Supply/Return now certified that it does not make any difference is a world leadr in HVAC

Are having a real problem or are you seeing one that may come up?

The tonnage of your coils would indicate that the manufacturer is not totally wrong.

The coil configuration is the question, the fewer the rows of coil tubes the less the flow of the water effects the outcome of performance.

Do you have a balance log?

As to capacity - every unit has some factor of performance built into its design.

No allowance to tolerate any reductions in its capacity, is to say that the load never changes. This can happen but not under normal operations.

The total design criteria comes into question if this is the case. I assume that this thread is related to other questions you have posted lately.

WHAT IS THE REAL ISSUE?

The real problem is that the OEM and the fellow responsible for the faulty in/out chilled water connections is telling that why birth of babies are thro the vagina of a woman in the world? Why it can not be also through the asshole?

Now that's what I call a wonderful sense of humer! Thanks for the laugh :>)

It sounds like you are sure someone has cheated you. I was only trying to get the facts. There is no doubt that the coil is not installed properly. Finding out if the problem is real or perceived will take more information than you have given to us. If you only want us to agree with you - The coil is piped wrong!

The real effect takes more work.

Good Luck

I tell u really what has happened. OEM has standardized 3 ROD ch. water coils for FCUS with RH side connection inculding Supply/Return lables. When an order is passed on to the assembly section, it is OK as long as RH connected FCUs. But when an order for say 50 RH and 50 LH connection FCU is passed on to assembly section for fabrication, they simply horizontally turn around the coil by 180 dec, assemble and despatch it without changing the Supply/Return lable. The Great All Rounder designer even after the fault is pointed out by site engineer gives go ahead as per OEM lable without applying his mind or checking with OEM. The all rounder goes on vacation and the writer happens to handle the project during his absense and noticed the mistake. When the matter was taken up with OEM, instead of admitting the mistake and advising corrective action, pleads that it does not make much difference. And when this matter was checked with another leaders in HVAC in the world, they said one of their client's project in Mecca also had similar fault and when they refered to us for clarifications, we advised them to re pipe as it will make lot of differences in not only LAT but as so in leaving water temperature and the efficiency will come down as much as 33%.

Make the contractor repipe them counter flow as they should be.They will not perform with the best efficiency. Let the customer who is paying the tab make the decision with your input of course. The OEM can say anthing he wants but if problems arise will he come back and repipe the job? I don't think so!!

I agree with shogun you have to achieve counter flow or you don't pick up the latent, if units were labeled wrong that's the vendors problem. I have seen this happen before where it ruined the cieling tiles because the humidity wasn't being removed, the school system went back on the contractor 5 years later and made them change it our they would never be allowed to bid for that school system again.

Actually the coil has been fixed upside down and despatched by the manufacturer. The site engineer did not apply his mind and connected the in/out pipes acording to the lables. Now the ch. water in has come on the return air entering side with air vents and ch. water leaving has come on the air leaving the fcu without any air vents.

The OEM says it dosnt make any difference in efficiency and it is not compellsory that the air vent should be at the out let header. Even if it is in the inlet header it serves the purposes, he says. They also tell as an OEM, either consultant or client can not dictate them to make like this or that and they have the right to change in keeping with their R&D. Now the customer says that he wants the things as per the OEM's and contractor's approved submittals and nothing more or less. The supply of FCU not confirming to approved submittals amounts to dishonouring contractual obligations. Comments are solicited

Any engineer worth his/her professional degree knows thea counter flow cooling coils give the best heat transfer. in other words the coldest water goes in the end of the coil as the air is leaving the coil. They have to make it right

Thanks for ur forth right comment Shogun. But u did not tell anything about their contention that the air vent in the inlet header will b sufficient and it doesnt make any difference wether it is in water in header or water out header of the coil.