I have a 24 year old Utica hot water furnace that for some reason does not want to heat our downstairs when it is very cold outside. There are 2 zones, with Taco valves on each. It was fine up until last year, and we had a furnace guy in who said that there wasn't any difference in the temperature coming back into the furnace and said it was because our baseboards needed to be cleaned. We cleaned them all, and it seemed to help some. But, with the cold snap today, we are running into the same problem. Upstairs is fine. Both sets of pipes are hot - so we are at a loss as to what could be causing the problem.
Thanks for any suggestions that can help us figure this out!