refrigeration mystery

[rourkeh]

I just replaced the evaporator plate for one of my freezers. I have a Frigaboat system and could not get a new evaporator with the quick connect ends where I am so I bought a Dometic evaporator and changed the connectors on the compressor. I hooked everything up bled the air out and charged the system with r134a. I checked the connections everywhere with a leak detector, no leaks. Now here is the weird part. Everything was working fine, the plate got cold, thin layer of frost, and over night the temp dropped down from 80f to 29f and then around 28 hours later the temp started going up and when I put my gauges on the compressor my reading which was previously just over 10 lbs was zero. It seems all the gas was gone but I can't find any leaks.
Anyone have any ideas?

[Typhoon]

Do you have a high side service valve you can try ?

Regards John

[rourkeh]

I have service valves for high and low side. But the pressures are correct after charging. 12 lbs and about 120 lbs. The system maintains these pressures for over 24 hours then all of sudden looses all charge. ???

[Typhoon]

When you were evacuating the system , did it hold vacuum ?

Regards John.