Air separator question

I'm planing to add an EKO or a tarm to my existing gas boiler and baseboard heat do i need a second air separator and expansion tank? Any one using a tarm without storage and how well does it work?

The Tarm is pressurized (12 psi nominal), and you will need an expansion tank and air separator for the Tarm. The tank will need to be sized for your installation. There may be ways of plumbing to share an air separator and expansion tank. You also will need air bleeder valves at high points in your system to prevent any airlock.

If you use the Tarm (probably also true for Eco) without storage, unless you have a high, sustained heat demand (approximately equal to output capacity of the boiler), you will have idling times of occurrence and duration based on your system. Each idling period introduces inefficiencies into the wood boiler system.

I don't think you need a separate air scoop, and you can probably get away without adding another tank, depending on how your current one is sized, because the extra capacity of the new boiler, etc. might change your needs. Your best bet, however, is to add a second exp. tank on the wood side, especially if there is a way to isolate the wood boiler from the rest of the system. You don't want a situation where your wood boiler gets isolated from access to the tank. Another tank supplies a backup, which is always good.