Hey guys, I have found a few answers to some problems in the past over here, but I cant find anything for this problem so I thought I would register and ask the question myself
I am a commercial tech with a bit of refrigeration experience. We have a restaurant that has begun having some problems with their walk-in and I am not sure what to try now.
Our customer has an older building and his walk-in freezer was waterlogged and the walls were buckling out and causing him a mess with ice on the floor. He decided that he did not need his freezer anymore and put in a deep freeze and a few standup freezer and got some guys he knew to tear down the old freezer. They did this on a Saturday (I had no idea it was happening) and Sunday morning I got a call from him about the cooler.
Apparently the guys he hired must have done something to the cooler (no one has gotten a straight answer yet) because he was telling me he had a leak(I never found a leak in the system). In a panic he called a guy he knew, because I was separated from my phone on Sunday morning for a few hours. It was a 409a system and the guy he called dumped in a bunch of 134a and told him it would hold him until I got there. Once I arrived, I recovered the refrigerant, replaced the drier and pulled a vacuum and charged with new 409a. Things looked good but he called me Tuesday and told me it wasn't working anymore. I returned and the unit was pumped down, but the solenoid valve was open. It eventually cleared and began running properly, but after a few more days, it pumped down again and would stay pumped down for several hours before clearing and running.
After replacing the TXV and the solenoid vave, I took them apart and found no visible flaws, and the strainer in the TXV was clean. Well, I have no idea what the problem is, but every week or so, the cooler will just pump down for 3-5 hours and then begin working properly. I feel confident that there is no moisture in the system due to the drier replacements and the multiple vacuums I have pulled. I am beginning to wonder if someone has put some leak stop in the system at some point and that is causing the problem. I think my next step is to do an oil change on the system and try blowing out the lines again, but I feel like I am spinning my wheels.
Anyone have any ideas or seen this before?