Self-circulating water home heating systems can create massive problems for consistently heating your home. These systems encounter problems when operating in homes with several levels of heated rooms, due to the effect that gravity has upon this water heating system. Rooms with excellent water circulation can overheat, while poorly circulated rooms may suffer a cooler climate. One of the most reliable solutions is to install a flow control valve for each room, which can help to create consistent flow among different rooms and water heated zones. Adjusting these valves properly is crucial to this consistency.
Place all of your thermometers in the same heated room. Wait a half an hour, and remove the thermometers which give an unusual reading from the others. Turn the heat up in the room by about 5 degrees, and wait another hour. Remove the thermometers which give an unusual reading. This will give you a group of thermometers that reliably read temperatures the same way.
Place one thermometer into one room that has no heating flow control valve, and one thermometer into each room that does have a heating flow control valve.
Set the thermostat to create a comfortable, desired temperature in the room with no heating flow control valve. Wait one hour, and check all of the thermometers.
Open the flow control valves counterclockwise 1/8 of a turn in all of the rooms which are colder than the room with no flow control valve. Close the flow control valves clockwise 1/8 of a turn in all of the rooms which are warmer than the room with no flow control valve. Repeat this step as necessary until the temperatures in all the rooms match the temperature in the room with no flow control valve.