As mentioned tha's typically a Taco zone controller or also Tekmar has controllers for that. Depending on the application, Tekmar can be much more capable for the money
I would look at the application by seperating the boiler plant, two boilers, from the distribution, 10 zones. Type of boiler makes a difference, condensing type gas or non condensing type. If non condensing type you would need some type of boiler return low temp protection, a loading unit, primary secondary pumping, something ...
And there's something called hot water reset.
In a regular size house were the boiler is oversized and energy efficiency just gets lip service, that's where you will see a typical zome controller.
You are describing something much larger, probably 10K sf or more, and with the wrong control scenario it may never work properly. If you get or cause flue gas condensation in non condensing type boilers, you can also get less than 5 years lifetime on the boiler.
If you want boiler staging with lead lag, hot water reset, boiler loading to maintain 140 deg boiler return water and avoid flue gas condensation inside the boiler, you would have to look at how it is plumbed and understand it. The controller, Tekmars are made for that. Honeywell certainly makes something for it but they can be harder to obtain.
Two boilers probably should be plumbed primary secondary, so the boilers have their own boiler loop, each boiler has a slave circ, there's a primary loop circ. Hot water reset would seperate primary and secondary loops and join them with a variable speed (reset) injection pump or three way valve between them.
Start with a design before wiring it.
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