Hot water baseboard heat - Intermittent air in piping

[goshenHeat]

Location: Morgantown, WV
Heating system: Oil fired boiler, Hot water baseboard


About every 2-3 weeks, I hear air in the hot water baseboard piping when the furnace starts. This only occurs for one day and then I do not hear the air for another 2-3 weeks. There is a working air purge on the boiler (I can occasionally hear the air escaping). If the boiler + piping is a closed system, why is the air noise intermittent? I would think that eventually all of the air would be exhausted through the purge. Or is this the case that there are air bubbles trapped in the piping, perhaps at corners, and that these air bubbles occasionally escape and cause the noise?

[HayZee518]

bubbles

that could be true.
why do I have to burp my waterbed every few months? same reason. when you heat something, some gasses form from the heat out into the system.
eventually they'll reach an equilibrium.

[goshenHeat]

that could be true.
why do I have to burp my waterbed every few months? same reason. when you heat something, some gasses form from the heat out into the system.
eventually they'll reach an equilibrium.

Makes sense - that's what I figured. Still seems weird when I can go 3 weeks with nary a sound, then one day I hear lots of gurgling.

[driz]

I always thought thats what those little pressure cooker looking gizmos with the tire valve looking thing sticking out.did that sat on each zone or on top of the boiler. (Bleed air) You can also bleed it at the drains for each zone too if you get bubbles in there. I never had any bubbling in mine till I quit using it . When, on the rare occasion I fire mine up nowdays it burps and farts and rattles for a while but settles right down. If it keeps happening I would think you are getting air into the system.