Leaking pressure safety Valve (?) on hot water gas heater system

YOFJAB

I bled my radiators today and alittle while later I heard a loud noise from the basement. I ran down there was water flowing from the gas heater -water pressure pipe. The safety release valve must have opened ( I think that is what it is called).  I got a bucket etc and it eventually slowed down. It never really stopped dripping even when I reset the valve. A friend told me it  could take a few hours to really re set r recalibrate (?). The heat came on later ans when I went too check on the drip, there was a stronger almost solid drip coming out of the valve pipe--and of course it was hot water now.  I turned off the heat and tried re setting the pressure valve covering again.  Now it is a slow drip again. Even if it stops dripping I am afraid to have the heater some on again.  I bled a radiator of a cup or two of water.  I tried another radiator and nothing came out--no air or water???

The psi says about 12 or 14 ( two story old house).  Any ideas?

YOFJAB

update

UPDATE --the pressure safety valve finally stopped its little leak dripping -after about 5 hours.  But not sure if it is because the heat is off and the water/radiators are cold or is it re set gain properly. Afraid to turn heat back on --will the pressure build up again and the leak start?  And the psi pressure no looks like it is 6 or 8.  Only ar comes out of one radiator,  COuld the system have lost that much water? Or when cold it registers that low? Can I put heat on to test with only 8 psi?