Air Dryer problem - Boge

[tvrao]

Can somebody please advise me on the following problem.

Equipment - BOGE Refrigerant air dryer, model D670, type-429,
R134a, 17kg, LP/HP op. pr are -16/20bar.

The above dryer was tripping on LP earlier. then on doubt replaced the filter drier and cleaned the expansion valve and put back. gas charged but the problem is not solved. amount of gas charged from lp side is about 15kg (not allowing further due to the tripping on LP). we tried by heating the gas cylinder also.

observations-
when compressor is in running, HP side reading is 19bar, LP is gradually coming down to 2bar.
There is ice formation on expansion valve & up to evaporator inlet.
no icing on evaporator & temp is around 40deg.
no cooling on evaporator to accumulator piping

is there any chance of complete choking of evaporator?

there is also a bypass tubing (flo-con installed) from HP to vapor line.

Please advise what to do.

regards
tvrao

[chemi-cool]

You say there is ice forming after the TXV, I would check that it hasn't lost the charge, orifice can also be a problem, replace it and try again, its the cheapest part of the system.

[glenn1340]

Looks like a restriction at the exp valve. Just an idea try taking the bulb out and putting it in hot water to see if that will open the valve , keeping an eye on the lp whilst doing so.