Dryer tripping on Low Pressure

[tvrao]

Hi,
Can somebody help me, i am in a big trouble.

I have a refrigerant air dryer (Boge) running with R134a and fitted with hot gas bypass pr.regulator. It is was tripping on low pressure on reaching suction pressure below 20psi. I have done many things to find the problem but not yet solved.

symptoms-
from txv delivery to compressor suction point is getting too chilled
LP is coming down from 50 to nearly 5psi in 2min. (Lp set at 20psi and tripping)
ensured there is no leak in the system.
Hp is near to 180-190 psi

in the first step i have changed the txv, cleaned the suction and discharge accumulators, flushed all the lines and tried - result is same.

in the next, removed the pressure regulator, opened it & found internal parts are choked with contamination, cleaned and fitted back, again tried. During operation, found gas is not bypassing through it during low pressure conditions - result is same.

next, removed the pr regulator and arranged a bypass solenoid valve and made it operative through a pressure switch (bypass on when suction pr below 40psi and off above 30psi). condition is little improved but suction pr still getting low.

I have also tried with close & opening of the txv adjustment but not much affect

can somebody tell me what could be the reason, is there could be any choking in one of the evaporators. pl suggest

regards

[RBM]

Does the system have a liquid line drier? If you have found contaminants in the system then it would be worth changing the drier.....You could put your hand on both sides of drier if you notice a temperature drop (when running) then the drier is probably blocked.

Good Luck

[tvrao]

Does the system have a liquid line drier? If you have found contaminants in the system then it would be worth changing the drier.....You could put your hand on both sides of drier if you notice a temperature drop (when running) then the drier is probably blocked.

Good Luck

Yes, the filter drier is fitted but it is also found ok. kindly suggest for any other reason

[joe-ice]

Yes, the filter drier is fitted but it is also found ok. kindly suggest for any other reason
How did you diagnose the drier as ok ,high side is too high for 134a ,appears you have a partial blockage somewhere ,agree with rbm change the filter drier

[install monkey]

a temperature difference of over 1 deg is classed as a restriction, tev adjust?? is the gas charge correct?

[Murre]

Pull out the R-134A and check the charge and re-charge the system. Replace the dryer filter with correct new one. Adjust system correctly again (txv and hot gas bypass pr.regulator).

What about cold side air flow?