heat pipes 2 and 3 don't have a heat capacitance and conductance value listed when you mouse over them, it's a similar thing for many other objects. heat accumulators, burners both fluid and solid.

Must be a new thing they've added recently.

I'll look into it.

in the current version, heat pipes 2 have the highest heat throughput of heat pipes if you were interested in the photos and data I have on this I could share.

the highest heat throughput I have found in my testing is accumulators at a functional 450mw vs, 41.9mw for vanilla heat pipes, (which are rated at 1GW...)