Digital scroll condensing unit

[sean1]

Hi
I have to look at this unit tommorrow any advice greatly appreciated
fault is its running 5 indoor refrigerated cabinets but 1 unit fluctuates in temp from 3c up to 20
another engineer reported that it only comes down to temp when the unit next to it cuts out and requires no cooling ?
Any thoughts I have not done much on these before any heads up or thoughts would be great
thanks

[chemi-cool]

Lack of refrigerant? Leak?

[Brian_UK]

Undersized condensing unit?

[Glenn Moore]

Hi Sean
Often these units have never been properly commissioned as to save money they are often installed by split bashers with little fridge system knowledge. the digital scroll has an unloader head which controls the systems suction pressure . The controller is set up to control the systems suction pressure by unloading the compressor, this allows the condensing unit to operate at reduced capacity when one or more of the cabinets are satisfied. So the suction set point in the controller needs to be checked against the requirements of the cabinets ie the suction needs to be approx. 8Deg C below the lowest cabinet set point temperature.
The cabinets also need checking as many of these cabinets use electronic expansion valves and often the control sensors for the superheat control are in the wrong position on the evaporator, and may need moving to a better position. If there TEVs checked their superheat setting and adjust as required