I just bought an old house with a Burnham Jubilee boiler. It most be at least 40 years old but checked out fine when I had it cleaned out and serviced. My system has one circulator and three zones. A honeywell aquastat L8024 controls everything. Lately I've noticed that the circulator is running even when the thermostats are off (not calling for heat). It doesn't run continuously but does run when I think it shouldn't be (all thermostats are off). Could this be normal operatation or is something wrong? Thanks in advance for any help.

Could be normal if they have a return loop in the system. many ytimes the boiler is setup to stay hot all the time and the circulator is setup to circulate while the burner is running.
If you system is working OK I would say just to have it checked on the next service.

Thanks for the response. The system seems to be working fine. No problem with heat. As you suggested, I'll have it checked during the next service. Thanks again.