I'm a DIYer that recently soldered a busted water pipe in my crawl space so I felt confident I could replace a dripping stop and waste valve in my heating system. After replacing the stop and waste valve with the newer ball valve I noticed my thermostat took a long time to heat up the house and there was a constant gushing sound in the pipes. I figured I needed to do some bleeding at the valves, but after an hour, I still kept hearing the gushing sound, but the heat was on so I thought it was ok...Well after I came home today I found water gushing out of the pressure relief valve in back of boiler!! I turned off the power, I tuned off the water coming into the system as well as the valves on the supply and return pipes into the boiler, but the relief valve is still dripping!!!

Was changing the stop waste valve to the ball valve the reason for this? Or was it improper bleeding? Lastly, how can I correct this?

I was reading some other post about the expansion tank, but mine does NOT have a shut-off valve between the tank and the boiler. I do have that air relief thing in between the expansion tank and boiler.

Boiler is a Peerless WBV-03-WPC
Expansion Tank is a Watts Regulator ET-30