Steam boiler with hydronic heating question.

chandlers

I have a commercial system with dual 500,000 btu modulating steam boilers. There set up to lead / lag off the steam pressure. The system runs at 6 psi.

The primary boiler is water tapped with to heat exchanger for domestic hot water and water to air heating.

The system is setup for a single boiler to run our normal equipment during the summer. There are processes where we use both boilers during the summer. During the winter the second boiler runs more often.

I'm looking to change over to a steam to water heat exchanger and getting ride of the water tap on the side of the boiler. I'm wanting to do this for the redundancy after loosing heat this winter during a cold snap that left me with barely any heat for a weekend.

What do I need to know before calling my installer about changing this?
Is there a different way that would still provide redundancy?

EBEBRATT-Ed

I guess if you don't mind having to make steam all the time you can. You would would need 2 steam to water heat exchangers 1 for domestic HW and 1 for your hot water heating loop. Feed the steam supply for both heat exchangers off the steam header common to both boilers

EBEBRATT-Ed

As an alternative you could pipe water off each boiler to both heat exchangers but it's going to get very complicated. You would need motorized isolation valves.

Two steam boilers cannot be connected below the water line unless check valves or motorized valves are used. This is to prevent a leak in one boiler from draining the other boiler

chandlers

I feel it would be better of using a single steam to water heat exchanger and a water to water heat exchanger.

Sounds like a rats nest tapping the water from both boilers with electronic valves.

This gives me more to think about. thanks