Low Suction Pressure- High Superheat (evaporator outlet)

Probable Cause:

Starving evaporator.

Light load condition.

Poor distribution through evaporator causing liquid to short circuit through favored passes. At full load
there should be no more than 5 of difference in superheat between any two circuits as they enter the header.

Compressor oversized/evaporator undersized.

Uneven or inadequate evaporator loading due to poor air distribution or brine flow.

Dirty evaporator filters.

Coil icing.

Frozen or slushed chiller.
Low water flow thru chiller.

Excessive accumulation of oil in evaporator.



Shut off some compressors, install hot bypass.
Unload compressors.

Slow down rpm of compressor.

Check process flows.

Clamp power assembly remote bulb to free draining suction line.

Clean suction line thoroughly before clamping bulb in place.

Install a properly sized refrigerant distributor.

Balance evaporator load distribution (i.e. check air flow
over entire coil surface).

Balance the components to load requirements.
Balance evaporator load distribution by providing adequate air or brine distribution.
Clean filters.

Check, reset, or replace defrost controls.
Check control valves for proper settings.

Clean strainers, balance water flow check pump.
Alter suction piping to increase gas velocity to provide proper oil return, or install an oil separator, if required.