Hot water heating system - air at top of pipes?

Chuck_17

Picture an existing 3 story building with HWS & HWR risers around the perimeter fed from mains in the basement. Each set of riser may serve one room on each floor. If the top floor fintube was removed so the risers just ended some where above the second floor, and vents were not installed at the top of the risers (air accumulated at the top of the risers), would the water flow on the lower floors?

Assume it would be very difficult to get to the risers above the second floor due to the existing building construction (to get to vents or to remove the pipe).

To partially answer the question, vents need to be installed somewhere just to get water up the risers in the first place. If the vents were installed at the second floor level, there would be air in the pipes above the second floor. This can’t be good even if the water did flow.

I think we need to install vents at the top of each riser.
Are there not vents with extension tubes?

Gordy

Put a valve on the riser.