Taco Switching Relay POWER

Hi all, I recently purchased a Taco SR502-4 Switching Relay in an attempt to clean-up/simplify a natural gas hydronic setup at my house. I *thought* I had things wired up correctly to at least check some initial functions, but I can't even get the power LED to light up on the Taco! Here's what I've checked so far... --Coming from the break panel I have 120VAC terminated into the 'INPUT' of the Taco (N - WHT, H - BLK, ground - Copper) --I checked continuity across all the fuses and they're all buzzing. (Plus, they visually look fine.) Is there something else needed to power the PC board of a Taco? I have had zero luck with the documentation from them, honestly. Happy to post more pictures if needed. Thanks! A few things to note here -- I replaced the stock transformer with a beefier one because I plan to power two separate thermostats and I *hoped* the boiler 24VAC circuit, but I haven't been able to get that far due to this issue.