Low side issues

[Outlawcrewcab]

I have a rheem heat pump that keeps pumping the low side down. Ac guy came and replaced the expansion valve first. Work good for a day or two. Then same thing goes into lo press lockout. Ac guy came back replaced online filter same issue. Some times I can reset after it set few hours and ac will work for awhile. Or I can turn it on heat after rest let run for a few. Then go back to ac and work. Then it will pump it self down. Ac guy lost. I'm lost. Watch the gauges when it happens. And low side just drops down to zero and machine turns off. Any *

[Freon]

When set to AC, what are the low AND high side pressure * If the high side is too high then a block in the line is possible. But to have this problem happen when no one has opened the system is a puzzle. Check the high side service port to be sure it's wide open. Before this problem first occurred, did you have any work done on the *

[heatseeker]

get a new ac guy one who can figure it out and ask for your money back on the parts already replaced cause it was misdiagnosed.