My Central Boiler 5036 has been running continuously for 5 years and 1 month. I keep it going all summer just to heat the hot water. My Taco Model 009-F5 Circulation Pump just died. The plastic impeller had disintegrated and was mostly missing. This is the first problem that I have had with the furnace. It boiled over and I lost about 4” to 5” of water. I replaced the water and ordered Permanganate so I can test the water to see if I need to add corrosion inhibitor. I also ordered a gallon of 1650XL Corrosion Inhibitor Plus. I replaced the cartridge with Cartridge # 009-021RP. It is working but apparently the flow is obstructed. I have a water to water heat exchanger. My guess is that the heat exchanger is plugged up with pieces of plastic from the impeller.