forced hot water heating system doesn't provide enough heat in rooms?

Answer 1

I had what may have been a similar problem in my new home. Three bedrooms on one zone with a common thermostat. One bedroom was very cold. I had to expand the furnace manifold and split the zone into three. Each bedroom now has an independant feed from its zone valve and a dedicated thermostat. The changes worked very well.

Pictures of the project are available online here...
http://members.rennlist.org/warren/furnace.html

Answer 2

Also, close doors and turn off furnaces in any rooms you either aren't using or can deal with if they're cool. That will force more heat into the rooms you WANT to keep warm. Sometimes turning those furnaces off can be a pain though. Good luck!

Answer 3

Find out the BTU rating after making sure it's working as best it can, maybe it's minimally-sized and you'll have to add portable heaters.

Answer 4

Have your water pressure checked, also check for a leak or leaks in supply pipes (this will also decrease pressure).