which way is correct or better?

heatingFun

I almost done my new zone. I found I am piping as the A option on the attached diagram. But I think the B option make more sense. Do I need to correct it? I am using 007 circulator not the zone valve for each zone.

Eric_32

Very important... what are you using for heaters?

heatingFun

cast iron baseboard #9

heatingFun

how bad it is？ does it heat better as long as the pump is strong enough to push the water travel longer distance？

icesailor

As far as I can see, both are versions of a parallel reverse return which is correct piping and will give you equal flow pressures to the emitters. "First out, last back" where as a direct return is "First out, first back".

I've always found it difficult to install a PRR like you have drawn and the actual application has a place at the end where there are three pipes. Its easy if you can do it like you show and go around in a square. I usually had to leave pipes out of one side.

In one drawing, you show some sort of dead end by the supposed boiler. You shouldn't need anything like that. Or, I'm misreading something.

Eric_32

They both look fine to me as well. The only thing with that piping system, is the boiler will not receive any warm return temps until the cast iron is warm, as opposed to a monoflow or venturi system.

If you have a condensing boiler it will love it, but a cast iron boiler, may need protection from cold return water.

heatingFun

Yes, but water will flow longer distance in option A. That is my concern. My boiler is Burnham Alpine gas boiler. I think it is a condensing boiler.