Iced build up on distributors

[Derick Bantjes]

I often come accross freezer Evaporators in Freezer Rooms where there is an abnormal collection of Solid ice build up on the distributor tails after the TEV, but before they enter the coil. We defrost the ice and in no time its back again.
My question is, is this perhaps an indication that the feeding liquid line is undersized, causing pre expansion in the distributor.

[lana]

Hi there,




My question is, is this perhaps an indication that the feeding liquid line is undersized, causing pre expansion in the distributor.


It could be. If the distributor is sized properly, it will have high pressure drop.
Basically if the room temperature is below zero and there is high moisture then there will be frost on the coil and also on the distributor.
If distributor is iced up then it is very difficult to defrost it:eek: .
The best way is to wrap the distributor and its tubes with a layer of insulation (tape type).

Cheers

[taz24]

My question is, is this perhaps an indication that the feeding liquid line is undersized, causing pre expansion in the distributor.


I agree with Lana.
Its unavoidable where there is moisture in the air and low tempretures.
It has no detrimental effect.

Cheers taz.

[chillin out]

Your TEV is not set up correctly.

Make sure you have the right size of orifice and the superheat set properly.

Chillin:) :)

[nh3wizard]

On nh3 units thats very typical

[LRAC]

I often come accross freezer Evaporators in Freezer Rooms where there is an abnormal collection of Solid ice build up on the distributor tails after the TEV, but before they enter the coil. We defrost the ice and in no time its back again.
My question is, is this perhaps an indication that the feeding liquid line is undersized, causing pre expansion in the distributor.

I see no problem with the above it is a common sight on freezer room applications, the distributer tails never get any heat from the defrost heaters. Sometimes we mount the defrost probe on the distributor if the probe is terminating defrost too quickly. Not too many times though.

Lrac

[noddyhead]

I too have encountered this, however have found extremely low condensing pressures contributing to this problem as well as lack of expansion valve capacity. Especially noticeable on 404A systems?

[Samarjit Sen]

This happens in most of the low temperature cold room/storage projects. There is always moisture inside these rooms due to humidity and as such the frost formations can not be avoided. The only solution is what Lana has suggested.

However this ice formations does not effect the performance of the evaporator coils.