Deep Freeze - deep question !

[Daktarri]

Hey Sensei dudes  , im new and appreciate your being here !! . i have a burning question someone  knows the answer to - im not a novice or a Samurai but   i hope my question isnt foolish or anoying , lol. i mainly repair Fridges and Freezers and have done for some time , i  am semi competent and have reasonably good success.   My current issue is with  an old upright commercial deep freeze ( a Gibson ) ; the main issue on these is ( as you all must kno ) Selenoid / Capacitor/ overload. ok.. i replaced those and the compressor tests good - runs  , it runs and gets warm so i kno its working ( somewhat) .. The freezing  shelf coils inside  snake along and you can see the Freezing progress. .. now , in this case the freeze proceeds and stops very early in the system  -  ive had this issue a few times with others and want to kno what the likely cause is. my ( poorly ) educated guess is low coolant(?) - but in a sealed system thats not common , but .. if its an old unit , can coolant leak slowly untill it cant full charge the system , but can a tiny bit  , ? not a rupture or break , just a very slow " osmosis " (?) ..or maybe its a blockage issue ? drier ?..  id love to fix this unit if i can , these old deep freezes seem to carry on a long time  with a bit of Love and parts . sorry for my epic long paragraph-   ive been pondering and researching this for a while now and need your help..!! i appreciate any advice and instruction from my Sensei Brothers. Domo Arragato

[Budget Appliance Repair]

Low on coolant/Freon/R12 or R134a depending on age.

Usually when a very small leak and old you will start only getting the first coil cooling really good and building up with frost over a period of time and the last coils, (last 2 or 3 shelves), not freezing at all.

The first coil pass will be directly where the capillary tube enters into the shelf coils - sometimes starts at the roof coils and come down to lower or starts at the middle shelf coil/s goes to roof coil then back down to lower shelf coils.