I need to update the hydronic layout and have some basic primary loop questions

RacerX

Hi and thanks for letting me join here.

I'm hoping to get some answers to some basic primary loop questions. I have other questions that aren't quite as basic, but you have to start somewhere.

I installed a HTP Versa Hydro about 12 years ago, moving the boiler to a new location in the basement from where the oil boiler was. I did a temporary loop into the existing 1950s monoflow setup (using 3/4" copper and pex) just to get through the first winter. The house is all one zone with a single stat. 12 years later, it's still there. It works and for the most part it works surprisingly well, but it's time to update some things.

For right now I'm just looking to get the primary cleaned up. The current primary has a bypass circuit just using a ball valve, standard air scoop, Bell & Gossett flow control and circulator. All of that is now 20+ years old from the oil boiler install that was done around 2000.

1st question - Am I correct that I don't need any sort of bypass if I'm using a variable speed pump.

2nd question - Am I seeing correctly that the if I use something like the Alpha2 that it has a flow control valve built in, so I would not need an external spring loaded check valve to control passive flow?

3rd question/advice - old air schoop or spirotherm? Or both?

Thank you in advance for any help. I definitely have secondary loop questions as well. But I'd like to get this part clear in my head before moving on.