I have a gas furnace that heats water. The water moves through the house in copper pipes to baseboard heaters in each room. I have three zones of piping with three thermostats on each floor (basement, main floor, top floor). It seems that my gas furnace cuts off too soon. It heats the water to a pleasant warm to the touch temperature and stops burning. It's pleasant but not enough heat to warm the house. The furnace used to heat the pipes to a "ouch thats hot" temperature. Is there another thermostat on the boiler itself? Does it need adjustment to make the gas burn longer and make the water hotter? Do I need a new thermostat? Am I on the right track at all here?
Steve.

Gas boiler