Radiator making noise when shut off valve closed

godkin

One pipe steam system. I have two radiators each fed by the same pipe, but on opposite sides of the wall, that make a noise like water flowing thru a pipe when their shut off valves are closed. Never had this issue before, but the boiler was shut off and when it was started again there's this new noise. Both valves were open when boiler was off and restarted. Noise goes away when both valves open and radiators filled with steam. Have the valves just failed? They are from 2019. Pictures of boiler pressure and settings.

pecmsg

Is it possible the valves are not closed 100% allowing steam in but the condensate can't drain?

Intplm.

And the valves could have damaged discs obstructing the flow?

AdmiralYoda

Why is your pressure so high? Your older pressuretrol seems to have the cut in set right, what is the differential dial set to inside the pressuretrol? 1psi would be ideal which would give you a 1.5psi max pressure.

If your gauge is accurate, 5psi is way too high and your vents may get damaged at those pressures.

And lower your secondary pressuretrol psi to something like 3psi, not 10.

godkin

The differential dial is set to 1. Looks like the psi gauge will fluctuate between 3 and 4.5 during its cycle. I'm guessing it's not accurate since when I set the secodary pressuretrol to 2 it doesn't shutt off. My guess is the sound is the valve not sealing when closed. If i turn the air valve on radiator upside down would that stop the intrusion thru the faulty shut off valve on the radiator?

KC_Jones

What is the reasoning for closing the valves? Valves should typically stay fully open on a 1 pipe steam system. With the valve closed, even a new valve, it may not seal perfectly and some steam could get through. That steam condenses, but can't get back past the valve. After a few cycles of that the steam will be gurgling up through that water and making noise. It can sound like a percolator, or almost a rattling.

If you truly need the radiator turned off, rotating the vent as you said is the best way to stop it from heating.