Creating a CO2 loop during closed transfer

[Bobby_M]

Nailed it. Exactly the info I was hoping for.
That about sums up my process. Playing devil's advocate though - the pressure is built during primary fermentation, warm. Suppose 10psi is built up (no venting, spunding valve tells us the pressure it feels). When I crash temp, do I still have that level of carbonation in the beer? (Please excuse the noob questions). Thanks very much!

Yes, use the chart to understand the concept. If you achieve 15 psi during fermentation at 65F, you have 1.7 volumes of CO2. As you cold crash the fermenter to 40F (assuming no external CO2 is connected), the 1.7 volumes will be maintained but the head pressure will drop to about 4psi. It's reasonable and customary to set your CO2 regulator to about 14 psi and attach it while you cold crash since you might as well pickup whatever additional carbonation you can in the meantime, but it's not critical to do so.