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I have a GB 142 with a replacement block (no warranty ). I'm doing radiant in a garage and some snow melt at a later date. I'd like to pipe the radiant manifolds directly to the boiler. I don't have the orginal Buderus manifold or low loss header. Im going to add a relief valve, gauge, on the outlet piping of the boiler. Install a circulator on the supply pipe and pump right into the manifold. Do you think I need to add the di electric unions to the compression adapters? Any problems with pumping direct besides maybe a larger circulator?