I have a wood boiler set up with 4 zones and no storage. Each zone has a circulator and there are no zone valves. If the power goes out, will the boiler work on convection with a setup like this? Everything I read talks about zone valves and be sure to open the zone valves when the power goes out so the boiler will still function on convection and distribute heat to the house. I haven't seen anything that says much about a system without zone valves.