suction freezeing

[karimihassan]

Dear all co worker.
thanks for visiting my comment.

we have a air conditoin pakage unit (DX type)
it works with suction normal operation pressure approximately 4 bar.and the refrigerant of system is enough .
some time the snction line pressure goes down near 1.5 bar and the suction line begins to freezeing and it completely freezes.
-why the suction line freezes?

[charlie]

Considering the value of suction pressure you are defining "normal" I suppose you are working with R22.

Considering that sometimes the unit works properly I don't think this is a problem related with a defective power assembly of TEV.

More probably there is some humidity in the system that is freezing in the orifice that remains partly closed.

If you have liquid line filters with replaceable drier cores you can try to install new drier cores.

Obviously this can cure the problem only if the quantity of humidity is reasonably low.

Another option could be to decant the refrigerant, vacuum the circuit and fill brand new refrigerant but this is more expensive and will require lot more time.

[paul_h]

Besides all the refrigeration problems mentioned above, what's the airflow like? Is the fan, coil and filter OK? Is the fan motor faulty and cutting out on overload, is it a belt drive motor and bad/slipping vee belts?. Are the dampers or ductwork blocked? What's the temperature setpoint, is it set too low and icing up due to that?

[lldelfin67]

Hi,
Check your superheat, if it goes below 20F then you have liquid refrigerant flowing to your pipe the cause the freezing of thr suction pipe. Another is your pipe layout if your it not properly lay-out it will freeze the suction pipe too.