Specifications
4421 Tradition Trail ● Plano, Texas 75093 ● 972 -964-2700 ● 800-836-7472 
URL:  www.iscenclosurecooling.com ● Email:  iscinfo@iscsales.com 
SP-ENG-210-100-09 Rev 1.6          19 | P a g e   
  *3Note: Refer to Electrical Schematics for further diagnostics.  
Unit Not Cooling  
Is Compressor 
On? 
YES 
 NO 
Check 
Setpoint.  Is 
Setpoint 
below 
ambient? 
YES 
 NO 
Is snowflake 
LED lit on 
controller? 
Set Setpoint between 
70 to 95 deg F 
YES 
 NO 
Is evaporator 
Fan on? 
YES 
 NO 
Is there voltage to 
compressor? Use 
meter
3
Check for faulty 
evaporator fan
3
Measure Temperature at Evaporator 
& Verify Heat Load Requirements.  Is 
unit capacity adequate for internal 
head load? Possible low refrigerant. 
Is compressor 
thermal overload 
open? Use ohm 
meter.
3
Check for error code 
 CA,LA,HA,LA2,HA2, 
P1, or P2 
YES 
 NO 
Check contactor 
circuit. Does it have 
power?
3
 NO 
YES 
Refer to Alarm Signals 
in Digital Temperature 
Controller 
Programming Section 
Contact Customer 
Support 
 NO 
YES 
Verify contact coil is 
being activated. Check 
connectivity
3
, if issue 
persists component 
replacement may be 
needed. 
Contact 
Customer 
Support 
YES 
 NO 
YES 
Contact Customer 
Support 
Replace Thermal 
Overload. 










