Gurgling/trapped air in hot water baseboard heaters

[JOSEPH K. KOLLAR]

I have a forced hot water/oil furnace with two heat zones. The top floor zone has baseboard radiators. When the furnace cycles on, there is a loud gurgling sound and you can hear the water loudly rushing around through the radiators. There dont appear to be any bleeder valves on that loop. My oil company told me to attach a hose to the system, open a valve, flush it out until the water runs cold, then shut the valve back off. This works, but the problem reoccurs in less than a week. I understand that there is trapped air in there but how could it keep happening?? There is no evidence of water leaking out anywhere – I dont understand how air could get into the system.Any advice on how to solve this problem would be appreciated. Thanks!

[Ken ThomasParticipant]

Unfortunately, you can purge the system with a hose all day long and the air will keep coming back. All water has entrapped air in it. This air can be disolved in that it is microbubbles that you cant see. The colder the water, the more air it can hold. As you heat the water up this air is released. It rises to the highest point it can find. This happens to be the baseboard. So each time you purge the air out new fresh air laden water goes in, starting the cycle all over. The real way to solve the problem is to install a microbubble air eliminator. There are several on the market. Spirovent makes the one we use but B & G and Taco make them too. These have the ability to actually pull the air from the baseboard and eliminate it at the boiler. See the link below and it may help explain it.

[Ken ThomasParticipant]

Unfortunately, you can purge the system with a hose all day long and the air will keep coming back. All water has entrapped air in it. This air can be disolved in that it is microbubbles that you cant see. The colder the water, the more air it can hold. As you heat the water up this air is released. It rises to the highest point it can find. This happens to be the baseboard. So each time you purge the air out new fresh air laden water goes in, starting the cycle all over. The real way to solve the problem is to install a microbubble air eliminator. There are several on the market. Spirovent makes the one we use but B & G and Taco make them too. These have the ability to actually pull the air from the baseboard and eliminate it at the boiler. See the link below and it may help explain it.

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