ACQUITY CM / CH Error: Column active preheater over-temp fuse h/w fault - WKB4114

SYMPTOMS

Error: Column active preheater over-temp switch h/w fault

Error: Column active preheater over-temp fuse h/w fault

Error: Column {x} active preheater sensor h/w fault

ENVIRONMENT

• ACQUITY UPLC
• ACQUITY UPLC I-Class
• ACQUITY UPLC H-Class
• ACQUITY UPLC M-Class
• ACQUITY PREMIER
• Column Manager
• CH-A

CAUSE

Faulty active preheater (APH)

FIX or WORKAROUND

Replace active preheater

ADDITIONAL INFORMATION

The errors are only present when a particular column is selected in CM-A and column compartment door is closed and latched (there is a magnet on the top-left of the compartment trough cover which activates control of the active preheater once the door is latched)

Verify that the new preheater is heating.  If not, check the F4 fuse on the CH-A/CH-30A PCB or F3 and F7-F10 on the CM-A PCB

Use the correct APH for your model: What is the part number for the ACQUITY Active Preheater (APH)? - WKB7232

In certain cases the observed issue might be due to worn contact surfaces on the active preheater itself. Try to clean the contact surfaces before replacing the active preheater.