Upon firing up the gas boiler, the system was loud and the upstairs zone was extremely slow to heat. He said this was because he couldn't get all the air out of the upstairs baseboards (said there were no purge valves) that the water had yet to heat up to the proper temperature. He suggested we let it sit overnight and try it again.
Today the noises are gone, but there is now no heat in either zone. One of the two circulation pumps gets quite hot, the other only tepid, but no heat flows into the baseboards
Any help would be appreciated!