OK. is the flow check mechanically operated? i guess i'm confused as to why the check valve is called for here as opposed to mechanical zone valves.
if both zones had flow valves and one zone called for water, wouldn't both flow valves open up?s.
The check valve keeps cooler water sitting in one of the idle zones from coming out backwards and entering the zone that is calling for heat. This ensures that the zone calling for heat gets newly heated water from the boiler.
The check valve and the circulator pump inhibit but don't completely stop forward flow (gravity flow) of heated water through a zone not calling for heat.
A mechanical, usually electrically powered, flow valve can be installed to stop all flow through a zone not calling for heat but most folks consider this to be too much of an expense.
Tornado victims: Do not rush to rebuild. Take your time and look for and get a good contractor. Or consider selling the property and moving to a home that is ready to live in.