Which boiler models is the R2080802 kit compatible with

The SPDT contacts should be wired to the controller's safety interlock loop

This specific kit is designated for the return/water side

consistent signal without the attenuation common in standard glass fittings

and 405A models

Hartland Controls TRAN-75VA Transformer 321042-401 Which boiler models is theThe Hartland Controls TRAN 75VA Transformer is a heavy duty, 75VA step down solution engineered for multi tap versatility in commercial HVACR and industrial control circuits. Specifically designed to handle primary input ranges of 120 208 240 480V AC, this multi tap 24V transformer delivers a consistent 24V secondary output, making it a standard replacement for high demand applications including water pumps, food service equipment, and pool spa