Hello all just looking for some advice. My safety valve keeps popping on my furnace. Last year I replaced the automatic make up feed water valve due to leaking by and over pressurizing. I turned off the manual feed water valve before that and watched the furnace operation. It was working fine for awhile and then the safety valve continues to pop.... Maybe twice per day. The gauges on the furnace are in fact reading around 30psi when the safety valve relieves so i do not believe there is an issue with the safety valve. The extrol expansion tank seems fine to me it has two different tones when tapping on it and one side is warm and one is cold. Could there be a low pre charge in the extrol? What can I look into next? I have another automatic make up feed valve I could install but I don't think that is the issue. I had my furnace last cleaned in 2015.. would that be anything that needs to be looked into? Thanks for the help.