Arrived onsite to fix fault in water circulation system. Found leak. Removed pump from the electrical circuit. Isolated pump and drained water. Removed pump from the circulation system. Cleaned the flanges of crud. Corrected orientation of new pump. Installed new connection gaskets. Bolted in mew pump. Attached electrical. Purged of air. Tested the system and all zone heating. No further leaks. System working as it should.