RichieWrench or any other plumbing/heating experts out there willing to assist. I have a gas boiler for heat and hot water.
I have a leak from my 30psi pressure relief valve. Well i'm assuming since it's connected to the tube shown. see pics. Common sense tells me its hard water worn or failing for some other reason not known to me. When I contacted a plumber, who was very nice and told me to try to free the switch up by tapping with a hammer on top due to it likely being corroded or whatever. In the midst of our conversation he said something about having to drain the entire system prior to changing the relief valve and then refilling the whole house. This baffled me as there are shutoff levers literally everywhere. Of course he doesn't know that because we were on the phone but he did say it would be very expensive. So my questions (looking at photos attached) is/are Why can't i just shut off the levers and change these out. Is there some danger associated with not draining the system? Or will this introduce some unstoppable air in system and therefore render it useless until it is bled entirely?
It just seems I can just shut off the valves pictured and go to town and then turn them back on.
Please educate me.
My goal is wanting to change the expansion tank and the relief valve. The parts are under $73 shipped from supplyhouse vs I'm guessing $1000 from a plumber. He said very expensive and I live in the Boston area so everything is basically $1000 to start.