Unit

Unit Short Cycles

Questions	Cause	Remedy
What is the thermostat differential setting?	Control differential set too closely	Widen differential
Have you checked condenser?	Cycling on high pressure	Clean dirty condenser. Check water supply on water-cooled condenser
Have you checked Discharge valve?	Discharge valve leakin	Correct condition
Have you checked the sight glass?	Shortage of refrigerant	Reclaim overcharge
	Refrigerant overcharge	Reclaim overcharge
Have you checked the expansion valve?	Leaky expansion valve.	Replace
Is compressor hot?	Compressor-motor overload cutting out	Check for high head pressure, tight bearings, stuck pistons, clogged air or water-cooled condenser or water shut-off

Questions	Cause	Remedy
How long do the doors stay open?	Service load to high	Keep doors closed
Is the condenser clean?	Dirty condenser	Clean condenser
Are the condenser fans running?	Fans not running	Repair or replace
Is the evaporator dirty or iced up?	Iced or plugged evaporator coil	Defrost or clean
Are the evaporator fans running?	Fans not running	Repair or replace
Have you checked the refrigerant level?	Shortage of refrigerant	Repair leak and recharge
Is there air or other non-condensables in the system?	Non-condensables in the system	Remove from the system
Are all controls functioning properly?	Control contacts have frozen	Clean points or replace control
Have you checked expansion valve?	Plugged expansion valve or retainer	Clean or replace
What is Evaporator Superheat?	Evaporator Superheat too high	Adjust expansion valve to lower Superheat setting
Where is condensing unit located?	Location too warm	Ventilate area or change to cooler location
Is box well sealed from air penetrations?	Wall panels not locked or wall penetrations not sealed	Lock panels, seal penetrations or replace
Is system capacity sufficient for product load?	Product load greater than system capacity	Add additional units or replace

Questions	Cause	Remedy
Have you checked oil charge?	Insufficient compressor oil	Add oil to proper level
Are all refrigerant lines secured so that no rattling occurs?	Tubing rattle	Bend tubes away from other metal contacts
Are all mountings tight?	Mountings loose	Tighten
Is the noise coming from the compressor? Do you have LOW suction superheat? (Below 20¡)	Oil slugging or refrigerant flooding back	Adjust oil level or refrigerant charge. Check expansion valve for leak or oversize orifice