The unit cools intermitantly. I have changed the start device and it continues to do the same. It will cool down for a couple of hours then it will warm up for a couple of hours. Freezer coils not blocked with ice. Temp control or adaptive defrost control? Any help would be appreciated.

It sounds like the electronic control (Part # 2304099 $84.75). The thermostat either is on or off and has no timing function like the control cited above. Units with analog controls are much more reliable.You have a lemon.