Am I getting a Thermo-Siphon???

Just a quick question. I have a old house and currently (until next spring) on a single zone for the entire house. My coal boiler is below my living room in my basement and I expect this room to be warmer than normal because of the radiant heat that the boiler puts off. My supply side piping seems to go from the boiler to the back rooms in my lower floor and then to the living room last. My thermostat is in the living room, if my thermostat is never kicking my circulator pump on due to the excessive heat already there (it is set to 70 and it's almost always at least 72 -75 in the living room), then why are my back rooms so hot all the time?

Wouldn't ts stand to reason that if the C.P. check valves are working, then the back room would be colder than normal due to the fact that the pump isn't running because of the living room not needing heat.

So do you think I am getting thermo siphon or my C.P. check valve is malfunctioning allowing the heated water to pass by?

Thnaks

what is your boiler temps., is your boiler dumping water into your raditators. Feel your raditators to see if they are warm.Do you have floor registers/holes/air leaks in the back rooms allowing extra heat through the floors.

My boiler temps are 180 - 190 where I want them to be. The radiators (old Cast Iron ones) are usually warm. But i check a old response to a earlier post I had made and a few people had already confirmed my problem. I choked down the circulator running in between the boilers and this solved the problem. I came home today and for the first time, the thermostat was at what it was set at. Must have been creating too much pressure and opening up the C.V. on the house supply circulator. Thanks as always.

Why are you running so hot in relatively mild weather?