How do I troubleshoot a failure on this control board

with a 1/4" ODF external equalizer

polytubing connections

The "U" suffix typically denotes "Unitized" or standard retail packaging

The 5/32" outer diameter tubing is optimized for standard pneumatic fittings

Weil McLain 511-405-006 Ciculator Cartridge Els PW 17895 How do I troubleshoot aThe Weil McLain 511 405 006 Circulator Cartridge is a field proven OEM replacement part engineered specifically for high efficiency AHE Boiler models. Designed for professional hydronic applications, this wet rotor circulator cartridge replaces worn motor assemblies without requiring a full pump housing teardown, saving significant bench time on the job site. The assembly features a high grade centrifugal impeller and water lubricated bearings that