II have purged my system about 4 times and changed the circulator but the flow of hot water only seems to go to the basement and not the 1st or 2nd floor. The boiler fires up, I can feel and hear the circulator getting hot and the pipe from it but it doesn't go upstairs.

I drained the boiler several times but the heat still fails to go past the basement. Can the expansion tank have anything to do with it?

I checked all around the house there are no bleeeders installed anywhere on the baseboard heaters so I can't bleed air from them. What else can I do to get the air out if that is the issue?

  • Make sure zone valves (and the same with any other valve) are not stuck closed
    – aofkj
    Nov 14, 2017 at 3:03

2 Answers 2


For making the system work properly you need to follow a few steps.

  1. Make sure that the system pressure is enough to reach the upperfloors. 1 Bar equals in almost 10 m water (Europe)
  2. Make sure that there is no trapped air anywhere in the system. Therefore you need to find the bleeders on the heaters. They must be there. If you are sure that there are none you could carefully loosen the upper pipe connections one by one until air starts to escape and wait until it starts leaking. Then tighten the connection again.

  3. Once you are convinced that none of the heaters and /or pipes contain trapped air you should verify the water pressure in the system.

  4. Verify that the expansion tank is in working order. Knock on it. If it sounds hollow than the membrane should be good and the tank working. For this step you need to be sure that there is water everywhere in the system. If the tank is faulty you will start to loose water when it becomes hot. Finally resulting in the same situation you have now.


Decapod is giving you the straight scoop. In simplified form, get the water pressure up. Then go to the highest and bleed the air. I hope you are pumping away from the pressure tank. That helps. but the system will work either way if you get the air out of the system.

  • If you have copper / aluminum finned baseboard heaters and there are no bleeders then you must have a purge system. Make sure that you have 15 to 20 pounds of pressure in the system, then utilize the purge valves provided. If you are not familiar with a purge system, call an HVAC service company for help.
    – d.george
    Nov 13, 2017 at 10:29

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