Air bound return from indirect fired water heater

[cosworth]

I have a problem with my indirect fired water heater return line going air bound and burning up circulator pumps. Furnace works on que from t-stat on heater.

[Midwest]

I can think of a number of things that can cause or help cause air lock problems. A bad air eliminator, pumping to rather than away from expansion tank, improper position of the supply/return tees in the primary loop, etc. Without more data, it's just a shot in the dark. Can you draw us a schematic of the piping layout or submit some photos of the system? If you can do a diagram, include details making sure to list all of the items in the water food chain from the boiler outlet all the way back to it's return inlet. This would help considerably.

Is this a new installation or an existing one with a new problem? Another site to run this scenario by is heatinghelp.com. The guys there will also need more details. I sometimes have troubles reviewing photos, but some guys can pick all details out immediately. I need to see the system myself. You will probably need a boiler pro to accurately diagnose this one with a visit to the problem child. This website's members will give very limited DIY help as it's against the site rules. Greg

[casturbo]

Sounds like insufficient boiler system pressure.....the boiler has no less than 10 psi, right? Probably plumbed all wrong is my second guess.