Thank you all for the advice. Here's how the problem was resolved... (Sorry for my lack of knowledge and correct jargon) For the second floor heat (in our 45yr old+ house), apparently there is one loop of piping and each radiator has a supply and return coming off this loop. The hvac person installed valves (in the basement)on the supply and return "T's" of the problem radiator and also replaced the circulator pump with a variable speed circulator (so that he could push more water through). With the valves, he was able to shut off the flow to each end of the radiator (1 at a time)and was finally able to get the air out. He said the supply line is connected to the end of the radiator DISTAL from the bleeder valve - but that it doesn't matter...since it is a complete loop. This doesn't really make sense to me... but the heat is working now. By the way he said that he connected the radiator as it was before, and it must have been like this all along...??? So, hopefully my problem is solved, and we will not have constant problems with this radiator...???

Thanks for the suggestion. I took a quick look, and they don't allow any discussion of pricing. It might still be a good information source for my other questions, although I generally try to avoid sites that try to match up consumers with contractors who pay for this service. Also, I don't want to register at yet another site just to post a question. What I like about this site (That Home Site!) is that you can usually get some first-hand info from other homeowners in similar circumstances as well as from professionals who aren't competing for your business.

Raising water temps is one way to get more heat out of less baseboard. 160-190 comes to mind. Hot water heat is the most comfortable form of heat ever invented and you will soon love it. The boiler probably maintains a certain low limit temperature, usually 160 degrees. Some have cold start boilers, but let's stick with the most common. When the tstat calls for heat, the burner and circulator will start. The burner will run until the boiler water reaches it's high limit of, usually 180 degrees. At high limit, the circulator will continue to run until the boiler temperature goes below 180 degrees and the burner will restart shortly thereafter. This is called "running off the high limit". If the boiler water never reaches high limit, the burner will run continuously until the thermostat is satisfied. If you have a domestic hot water coil in the boiler and the boiler water temperature goes below the low limit because the burner can't keep up, the circulator will stop, the burner will continue to run until the boiler water get above the low limit, whereupon the circulator will restart. This keeps enough hot water in the boiler for the coil. This is called "running off the low limit". Your boiler may cycle without a call for heat, just to keep the water temp above the low limit for the domestic coil. A good explanation of how an aquastat controls a boiler, google Honeywell L8124A, or L8148A for cold start boilers, or L7224A/L7248A.

Mtrot: There has been a problem with the Whirlpool FlameLock water heaters - many of which have been sold by Lowes. That said, $400 is about right for a 40 gal gas water heater. You will need to get a few quotes, but I'd suggest that you consider an installation from Lowes/Home Depot. You will need a pan with a drain under the new heater (should have been one on the old heater) to prevent the problem you have now. You will also need to decide what to do with the damaged floor. Just an FYI: Often a "leaking tank" isn't really that at all but instead a leaking valve/fitting on top of the water heater that eventually makes its way down the side of the tank to the floor. Just something to rule out.