Runtal Baseboard Noise Upon Circulator Shutdown

NEMatt

I have Runtal three-row radiators installed in a few places in my house. Unsure of their age. Two short bathroom runs (<3ft each) and most notably in the main hallway of the house which is 13ft.

When the heat is on they run quietly after a little expansion noise, but the odd sounds are after the heating call when the boiler circulator shuts off.

The upstairs bathroom one does sort of a single short noise that I can best describe as crumpling a beer can I guess?

The very long rad downstairs however makes a tshhhhhh... thshhhhhh... tshhhhhhh, noise that you can hear propagate down the length of it.

All the rads in question work just fine and heat up rapidly and uniformly.

Thoughts? I suppose that their top pass is the highest point in each of their respective heating loops since they are taller than all the other standard baseboards. Might just try to bleed them?

mattmia2

Mine does that. i think it is the fact that the circulator is controlled by the end switch on the valve so the valve closes with the circulator still running and pressurizes the radiator briefly.