Air Bubbles In Baseboard Water Heater Pipes
Perhaps someone can help me save the cost of a service call! I have a gas boiler, 2 zone, hot water baseboard heating system. I "bleed" the three lines by running a hose out to the driveway and into a 5 gallon bucket. I turn off the butterfly purge valve, open the line faucet, then open the pressure valve. I do one at a time but do all three leaving the purge valves closed until they are all done. I let the water run until there are no bubbles coming up in the bucket outside. Then I shut off the pressure valve and close the line faucet, then open all three butterfly valves. The pressure comes up to 12 lbs cold to 22 lbs hot. This gets rid of the air noises in the radiators, but it seems to come back "too soon". I have already done this procedure three times this winter. Somthing must be wrong! I am thinking it is either the Amtrol Extrol, Model 30 and/or the Amtrol Float Type Air Vent, No 700, Max WP 45 PSI. Am I bleeding the system correctly, what does the Amtrol Extrol do, and does the Float Type Air Vent go bad? Here is a pic of what the system looks like. I would appreciate any help with my problem. Thanks!!!