We will replace pumps in the aster bed and the front bedroom. The new pumps will be Taco 007E pumps. They have the ability to remove rust flakes from the impeller. If unsuccessful after 15 minutes, it will shut itself down rather than burn out. We will raise the height of the pipes to 12" above the outlet of the pumps for less resistance on the pump. All 4 pumps will have auto vents to keep them from becoming air bound at the highest point. we will also back flush the flat plate heat exchanger. We will flush the system with a high pressure pump to try to get the rust flakes out of the radiant loops. (the cause of the pump failure.)