Hot water baseboard heaters are one of the most common heating systems used today. They are efficient, easy to maintain and relatively inexpensive to run. One job that should be regularly tended to is bleeding the system of air. Over time air builds up causing the heat to make knocking noises and loose efficiency. Bleeding the system does not require a plumber; this is a simple job that and do-it-yourselfer can handle on a weekend afternoon.
Things You'll Need
Turn the heat on 75-degrees and leave it on for at least an hour. This will circulate the water through the system thoroughly. It is best to do this job early in the fall when you can still open a few window to alleviate the heat build up in the house.
Turn the heat off and go to the basement or utility closet and locate the systems main tank. Gravity will now do the job of bleeding the air out of the system as the water sinks back into the central tank. At the base of the tank will be a bleed valve. It will look like a normal hose connection.
Stuff a rag a few inches into the valve to catch any water that drips out, or simply place a bucket beneath the valve. While the lower pipes will have the majority of the trapped are forced into them by the sinking water, some moisture is still likely to come out of the valve.
Turn the valve to the left to open. As the air and any water that comes out will be hot use a wrench to manipulate the valve and wrap your hand in a rag as a precaution. The air will begin to hiss out. Leave valve open until water starts draining out in a steady stream signaling that all the air is out of the system.
Close the bleed valve with the wrench and wipe up any spilled water.