air cooler uneven distribution check

[Lc_shi]

Hi sirs
One expert told me the method to check if the refrigerant is distributed well or not for a fin tube air cooler. The procedure as below:
Vacuum the air cooler and charge liquid refrigerant into it and watch the frost situation and confirm if the distributor is good or not.
I can't make sure if it's correct. Have you known this method? :confused:

best regards
LC

[andy bailess]

Hi Lc shi

The best way to check a multi port distributer is too leave the refrigeration system running but turn off the evaporator fan motors,remove the evaps end covers and look for the frost line on each curcuit of the evap. This will produce a frost line on all coils except the curcuit which is blocked,if all of the runs frost then there is no distributor problem it may be the TEV setting.

P.S don't leave it running for too long as you may have liquid refrigerant going back to the compressor.

[Lc_shi]

I think you're right. :)
thanks

regards
LC

[US Iceman]

Hi LC,

Why are you checking the refrigerant distribution visually?

If the coil circuiting is done properly and the distributor is selected correctly, these problems are non-existent.

The biggest problem I am aware of is the need for proper coil circuiting. If multiple distributors are used to control part load operation, you might want to ensure the coil circuit will provide a completely active coil surface.

Otherwise, you can loose control of the dehumidification of the air stream if the coil is only partially active.

[Peter_1]

We let it run normally and just one bend before it enters the main suction header (oppositeside of tehj suction header), you measure if all these last return bends have the same temperature.

[Dan]

I agree with Peter. But in the case of split coil distribution such as I see with the gentle air unit coolers that use low velocities out of both sides such as you find in meat preparation areas, I have struggled with even distribution dilemmas because I now have possibly unequal air flows.

Thus, you can have an unequal distribution that is caused by unequal air flow, or heat load. Always keep this in mind. This could apply to an A-coil in your home air conditioner, and also a horizontal refrigeration freezer coil in a reach in freezer.


Vacuum the air cooler and charge liquid refrigerant into it and watch the frost situation and confirm if the distributor is good or not.

Lc, this is a terrible idea for simple reasons. You only have one chance to look at it and your are done with your analysis. That's the first one that comes to mind.:)