I am having infloor heating circulation problems, My pump is running and the water at the pump is hot but it is not running through the rest of the piping. What would cause the water not to circulate?

Air in the system. Weak pump impeller.

Yep, distance between chamber surface & impeller surface no longer within operational tolerance. Happen to all centrifugal pumps sooner or latter depending multiple usage variables.but you should have noticed decreased performance long before this point.Based on the limited and insufficient amount of info provided suggests you don't intend to fix it yourself. You just want to be able to call bull with confidence if your repair tech tries to turn a service call with 20 min.s in labor to adjust the pump if his good hand is in a cast, into a big dog and pony show.If pressure loss occurred abruptly it is more likely the pump intake supply line is restricted by an inline strainer and/or prefilter.(very popular pump warrany requirements).simple and easy to rectify.If this is the case continued use of pump will case motor damage($$$$) If its pump cavitation ,continued use will also require seal replacement and will continue to leak past the seals till replaced (less w/ pump off -more w/ pump on. Shut down system, call service tech. Ask him to explain how it functions,how to do the general maintenance & how you can monitor your system for proper operating performance. Hope this helps you. I'd like to here about how it went from here!

Yep, distance between chamber surface & impeller surface no longer within operational tolerance. happen to all centrifugal pumps sooner or latter depending multiple usage variables.but you should have noticed decreased performance long before this point.Based on the limited and insufficient amount of info provided suggests you don"t intend to fix it yourself. You just want to be able to call bull with confidence if your repair tech tries to turn a service call with 20 min.s in labor to adjust the pump if his good hand is in a cast, into a big dog and pony show.If pressure loss occurred abruptly it is more likely the pump intake supply line is restricted by an inline strainer and/or prefilter.(very popular pump warrany requirements).simple and easy to rectify.If this is the case continued use of pump will case motor damage($$$$) If its pump cavitation ,continued use will also require seal replacement and will continue to leak past the seals till replaced (less w/ pump off -more w/ pump on. Shut down system, call service tech. Ask him to explain how it functions,how to do the general maintainence & how you can monitor your system for proper operating performance. Hope this helps you. I'd like to here about how it went from here!
Simply Stated!