constant Circ and backflow preventers

Mike_Y

I'm updating the current EFM PK boiler in our new to us house to correct for among other things: no air elimination, and circs that were placed on the returns. The layout is a 1 pipe diverter system for the main floor with fin-tube convectors and a second loop of 3 standing cast-iron rads in the basement that are all piped directly from a supply and return that are separate from the first floor. Each floor has it's own circ. All rads on both floors will have their own TRV and there is a differential pressure regulator on the basement loop. Standard pumping away from a Spirovent jr. with 2- Taco 007 circs. Both Circulators will be constant circulation and a Tekmar 256 will regulate for outdoor setback.

My question is pretty simple. There were B&G backflo preventers in the system on the 2 supplies before and I'm wondering if they are still needed with both loops running constant circ. I have them so my thought is to just put them back in after each circ unless there is sufficient reason to leave them out.

As a PS: The boiler is 30yo and will be replaced next summer, at which time I'll also add a DHW loop.

Ironman

You should leave them in since you'll need them when the indirect is added. Oh, they're called flow checks, a back flow preventer is what protects the potable water line.

Mike_Y

Thank you. That was my thought too. Just needed a way to proof my work. And Yes, Flo Check, not backflow.

Thanks again.