Dana sorry to have wasted your time with last post. Did not reread it. I didn't mean 60psi expansion tank. I mean jumping from a size 30 to a size 60. Radiators look just like the top picture you have. I'm just going to measure volume today and be done with it. I have a 5 gallon bucket and the sink is right there. I'm going to shut off the boiler. Turn off the gas and start draining. when I get lower i'll open the radiator bleed valves. Anything else I should know about draining and refilling a system?