Hi... Have a 10yo Amana side by side that has a low pressure access port (soldered) installed from about (3) years ago. Added refrigerant back then as evap was only frosting about 1/2 way down. Been colling ever since, although probabaly not as efficiently as should be. Started acting up the other day and I though it was time to add a touch more... got the frost line to 'just outside the box' over several hours of adding a touch (I know, very specific amount) and letting the system stabilize and coming back and looking at evap (evap cover was on, except when I was looking or course ).
Low side was in the 4 to 6 psi range and frost line looked good and stable, then the defrost timer caught me and cycled... when it restarted, the frost line ran all the way back to compressor and didn't retreat even after several hours of running. Before the timer caught me, the temp was slowly dropping and was in the 6 to 8F range, eventhough I was opening door to check evap about every 20 mins.
Any ideas on what to try?