a link with a video of the problem, the taco pump is a 007-870, the psi in the expansion tank is <5. the models of zone valves are 1311-102 and 1361-102.
SRM-60203A - boiler model. the auto-air purge releases air from the top. the water valve for fresh water is closed.
What is my problem? any thoughts? the last two time we had someone out to check it was $ a piece and we just don't have the funds right now. From what i can tell, it was last serviced in 11-12-07 when the new Taco pump was installed. the Expansion tank was installed at 1-29-07