Daikin blocked distributor

[Fridgy Dave]

I came across this problem today and it had me stumped. I work mainly on commercial refrigeration so i was wondering if anyone that worked prodominently on a/c has come across this before. I had an older Daikin 12kw casette unit flood back to the compressor but with very low back pressure and the indoor coilo temp was the same as the return air, after afew days the indoor coil completely frosts up but its like it starts from the compressor and works it way back. My theory is that the distributor is fowled, when the system starts it floods the coil and suction line, when the distributor freezes it blocks then the liquid is trapped between the comp and distributor boiling off in the coil but condensing again in the suction. If anyone can help me with this it would be greatly appreciated.

[monkey spanners]

What make you think it is flooding back?

What you need to measure is the suction pressure and the suction line temperature, thencompare these on a sliderule to see if it is indeed flooding back.

Could actually be short of refrigerant, i think i'd be weighing it out to see.

[frank]

If your distributor was blocked or partially blocked then i would expect that you get very uneven frosting on the coil, as opposed to 'the indoor coil completely frosts up'

A completely frosted coil on an A/C unit designed to operated above oC tends to indicate a shortage of charge, or lack of air flow or lack of load. Could also be a faulty metering device or sensor.

[Fridgy Dave]

I had checked gas charged and then reclaimed and weighed in correct charge.Checked electronic expansion valve and cleaned the indoor coil and fan to ensure optimal air flow.The very simple explaination for my problem which took me a long time to find out was that some idiot had disconnected 3 identical units then piped up 2 of them around the wrong way so sometimes the indoor unit was running then it switched off. Thank you for your suggestions though