Freezer Flatlining

[SULTAN]

I got a ColdTech/Minus Forty upright single door freezer which is giving me some problem.

What i mean by flatlining is that it never reaches its designed temperature which is set by thermostat.

Set point is set for -20 F But it only reaches to about -9 and keeps cycling.

Its charged with 404
Temperature probe is properly installed
Control was replaced with new digital one but no luck.

What could it possibly be?

[tony--1]

is r404 on the cascade side of it. just thats a bit cold for r404. need mo info ie. is there a subcooler ? wat is the second stage doing ? (if it has 1 )pressures stuff like that

[SULTAN]

This is not a cascade system.. Its a upright single glass door merchandiser.
Its a closed system.

[Slatts]

You say:

Set point is set for -20 F But it only reaches to about -9 and keeps cycling.

So what is it cycling on?
if not the thermostat, is it cycling on an LP control?

[SULTAN]

This unit has a digital controller that can be adjusted. I changed the controller and still same thing.

I finally solved the mystery and it was low refrigerant that was causing it to have low SC and High SH

[tony--1]

sultan

not much of a mystery after all . if it was just short of gas .

[Slatts]

So where was the leak?
I trust you found and fixed it?