I'm need to purge my hotwater baseboard system myself, and just want to run what I'm planning past the group to see whether there's any problems with what I'm planning. It's my first time doing this. It's a two-zone system, one on the main level and one on the lower level. The upstairs zone is 2 parallel loops. Boiler fires just fine and the family room/bedrooms loop heats well. Family room loop is on the same level as the boiler; the other loop is one level up. I run the system at 220 degrees and about 20 lbs. You can see a diagram of my system at [url]http://acornbay.textdriven.com/tmp/heating/hw_heating_system.pdf[/url], and a photo of the output side of the system at [url]http://acornbay.textdriven.com/tmp/heating/IMG_0869.jpg[/url]. I had the system worked on this summer, adding a short fin tube segment in the dining room segment to heat the floor in front of the kitchen sink, so some air probably got into the system. The problem I'm wanting to fix is that part of the upstairs parallel zone is heating fine (the dining room loop), but the other part is not (the living room loop). The radiator at the input end of the living room loop feels slightly warm, but is cold through the loop. I have purged both ends of that loop and get water at both ends. My working theory is that there is air in the living room loop that is somehow preventing parallel flow through that loop. 1. Can I safely close the valve that controls the dining room side of the loop, to drive all of the flow through the living room side? 2. There's a venting procedure in the Bell and Gossett Airtrol manual that I've never done -- any reason I should not do that? 3. Any suggestions on purging a long run? The living room run is probably 40' of Crane cast iron baseboard. Are there situations where on a long run like that you have to purge a bunch of water to get to the air? Other suggestions also welcome.

Sorry - I think this post wound up under the wrong topic! I was just wondering if anyone knows whether the cost to go with an electric vs. gas (what I have now) water heater has become more competitive, with gas costs on the rise. Should I stick with gas, or is electric a reasonable option? Thanks for any help you can offer.