I recently bought an old 3 story(mansard roof) house. It has hot water baseboard heat.(6 zones). The third floor and one half of the second floor are getting no heat. The second floor was working fine until yesterday. The boiler is gas and is working. There is hot water in the pipes in the basement. The circulators are going on. What could be the problem? Do I have to bleed the lines? There are spigots on each line in the basement so I can attach a hose to let water out. I also need a referral to a plumber in the Merchantville Area. Any suggestions?