54 High Pressure Switch On Error MP4000

Description 

High Pressure Switch On Error 

• Occurs during pretrip (PTI) test only. 
• Compressor does not start within normal time during high pressure cutout switch test. 
• Indicates: 
• High pressure cutout switch did not respond to pressure change within 5 seconds. 
• Air in refrigeration system. 
• Defective high pressure cutout switch. 

Corrective Action 

• Check discharge and suction pressure gauge readings. 
• Enter Manual Function Test menu. 
• Start the following components together: compressor 100 percent, compressor and evaporator fans (high). Discharge pressure should increase and compressor should stop at 2250 kPa, 22.5 bar, 326 psig (high pressure cutout switch opens). 
• Then start condenser fan. Discharge pressure must drop quickly (10 to 20 seconds) to 1550 kPa, 15.5 bar, 225 psig and compressor should start (switch closes).