Ice formation at the Service Valve of Split Air-Conditioner

[monowar]

[SIZE="5"]Dear Friends,

I am using a Qidi 18000 Btu/hr Split Air-Conditioner. But after starting the Air-Conditioner, Ice is forming at the Service valve which connects the Evaporator and Compressor. Then The ice covers the Connecting pipe gradually and after 5-6 hours later, ice started forming at the evaporator coil. I am making sure that, evaporator coils and fins are free of dust and they are clean. Blower is also working well. The air, that comes out from the evaporator has got a temperature of 11-12 degree. Room Dry bulb temperature is 27 degree and outdoor dry bulb temperature is 33 degree centigrade.

Can anyone tell me, why this problem is occurring?

[sedgy]

hi monowar,
I am not conversant with the model of your unit , but it sounds like the service valve on the small pipe which was called the liquid line, but on most units now this is where the liquid is restricted and so this pipe is now part of the evaporater < if the unit is on cooling< and so there will be frost on this pipe,
there is no problem occuring , hope this explains things , sedgy

[r.bartlett]

If it's the big pipe it's over charged
If it's the small pipe it's undercharged

[monowar]

@Sedgy: Liquid line is that that line through which the refrigerant goes to the evaporator in liquid state after expansion through Capillary tube. But, Ice is not forming on that tube. Ice is forming at that tube through which the Refrigerant comes out from the evaporator and goes to the Compressor. The ice frist starts forming at the service valves and then it covers the copper tube and then evaporator.

[sedgy]

hi monowar, there are two service valves on the cond, unit, if frost is forming on the larger of the 2 < the suction < this shows that its over charged < or the filters are blocked< or there is a problem with the air flow,
tell me are the copper pipes insulated ?