Suction Pressure

Suction Pressure Too High

Questions	Cause	Remedy
Are suction lines insulated properly? i.e. from outside of box to compressor. (Hot weather)	Suction lines improperly or not insulated	Insulate suction lines
Do you have the correct expansion valve?	Oversized expansion valve	Replace with properly sized expansion valve
Where is expansion valve bulb located?	Expansion valve bulb in improper location	Move expansion valve bulb
Is expansion valve bulb insulated?	Expansion valve bulb improperly or not insulated	Insulate expansion valve bulb properly
Is expansion valve in proper adjustment?	Expansion valve overfeeding	Adjust expansion valve until proper superheat is reached
Is system capacity sufficient for product load?	Product load greater than system capacity	Add additional units or replace

Questions	Cause	Remedy
Is the evaporator coil clean?	Dirty or iced evaporator	Clean or defrost evaporator
Have you checked refrigerant charge?	Refrigerant shortage.	Repair leak & recharge.
Where is unit located? What is air temperature entering condenser?	Condensing temperature too low	Replace or repair existing condenser control. Add if none exists
Are suction lines insulated properly? i.e. from outside of box to compressor. (Cold weather)	Suction lines improperly or not insulated	Insulate suction lines
Do you have the correct expansion valve?	Undersized expansion valve	Replace with properly sized expansion valve
Is expansion valve in proper adjustment? Is superheat correct?	Expansion valve underfeeding	Adjust expansion valve until proper superheat is reached
Do you have a pressure drop across filter drier?	Clogged filter drier	Replace core(s) or entire suction filter
Do you have a pressure drop across suction filter?	Clogged suction filter	Replace core(s) or entire suction filter
Are suction lines restricted?	Restricted suction lines	Remove restrictions or replace