Went to a walk in freezer that had stopped working a couple days ago. Found that the high pressure cut out had been tripped. Tried to reset it but I couldn't reset it. So I put a jumper in and checked pressures. HPC was set at 350 and head pressure was 375. Outside ambient was 105. Also found that the fan/defrost temp sensor have some how come apart. So I wired the evap fans to direct power so the fans would run all the time. Got the freezer down to 28 deg
Today I replaced the dual LPC/HPC and the fan/defrost sensor. Reset the defrost timer and got it going. Had it down to 24 deg in about a half hour.
My problem is this when I replaced the LPC/HPC the low pressure cut out was set at 0 and when the system went into defrost and the LLS closed the condenser would still run. I couldn't find any specs on what the LPC should be set at. I set it at 25.
I have never come across this before and wondered if anyone here had any ideas.