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I recently replaced 5' of baseboard radiation with a Buderus panel radiator. It is piped to the 3/4" copper series loop with one mono-flow tee on the return/downflow side of the loop and there is 15" between the mono tee and standard tee. I used 1/2" pex from the copper loop to the radiator and have checked and even switched the supply and return connections on the radiator. The radiator is above the loop and not more then 5' from the 3/4" loop. I get a steady stream of water out of the bleeder. The radiator will not heat after the initial filling. I did not purchase the thermstatic valve option. What am I doing wrong?