Add a loop

Snowmelt

2 questions ,
What aqua stat are you using for these set ups and what pumps are you using g ?

GroundUp

What set ups?

Snowmelt

My fault, the add a loop on a steam boiler

AMservices

Open on rise aquastat. 
3 speed circulator. 

Paul Pollets

3 speed bronze or stainless circulator

Snowmelt

I thought we want the biggest velute ( passage way so nothing gets clogged up

AMservices

Most of the time I only see basic 007 pumps being used in this application. 
I've never seen a bronze or SS circulator used on anything but domestic water. 
Maybe @Paul Pollets can explain why thats better. 

Paul Pollets

I've used cast iron circs, but get twice the life out of a stainless or bronze pump.

AMservices

https://heatinghelp.com/systems-help-center/how-to-run-a-hot-water-zone-off-a-steam-boiler/