suction line freezeing

[karimihassan]

Dear all my co worker.
thanks for visiting my comment.

our plant we have the air condition pakage unit(DX type).
the suction normal operation pressure is 4 bar during the suction line freezes the suction pressure goes down near 1.5 bar and then the suction line be comes freeze.weanwhile the refrigerant of system is enough.
why the suction line freezes?

[mohamed khamis]

Hi karimihassan

Welcome to this forum,

Ok if the suction line only freezes without the compressor and u mentioned the normal suction pressure is 4 bar and u got 1.5 bar it sounds u have excessive suction pressure drop inside the line causes the suction temperature to drop drastically and makes the frost coating. Each drop in suction pressure 1 bar the temperature drops to 3 K in R-134a. so u have at least 7 to 9 K in AC and most frequently the evaporating temperature of 7.4°C so the suction temperature reaches below zero.

Does ur system have accumulator ? if yes check it size it may be oversized selection of accumulator.

Check all the fittings and valves and the suction line design.? more data give more light.

Cheers

Mohamed

[Cofreth]

Dear all my co worker.
thanks for visiting my comment.

our plant we have the air condition pakage unit(DX type).
the suction normal operation pressure is 4 bar during the suction line freezes the suction pressure goes down near 1.5 bar and then the suction line be comes freeze.weanwhile the refrigerant of system is enough.
why the suction line freezes?

What is the on coil and off coil air temperature across the evaporator?
Probably a plugged air filter or evaporator coil or even a loose fan belt will cause this problem too.

[mohamed khamis]

What is the on coil and off coil air temperature across the evaporator?
Probably a plugged air filter or evaporator coil or even a loose fan belt will cause this problem too.

All the prevoius causes the evaportor to frost obvoiusly and then the suction line and the compressor

[lana]

Hi there,

Measure the superheat and make sure that no liquid is flooding.
Check the sub-cooling too.

1- LP low, SH high, SC normal, no temperature drop in liquid line ------------- Lack of expansion device capacity
2- LP low, SH high, SC normal, temperature drop in liquid line ---------- pre-expansion
3- LP low, SH high, SC low ------ Lack of refrigerant
4- LP low, SH low -----------Lack of evaporator capacity

Cheers