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A magnetic automatic stop valve formed in a container of a medical fluid administration system has one magnetic element located in a float and another magnetic element located proximate a valve seat. As the fluid level in the container decreases, the magnetic field established between the float and

A magnetic automatic stop valve formed in a container of a medical fluid administration system has one magnetic element located in a float and another magnetic element located proximate a valve seat. As the fluid level in the container decreases, the magnetic field established between the float and the valve seat eventually overcomes the buoyancy of the float in the fluid and attracts the float into the valve seat at which position the flow of fluid from the container is stopped. The float is formed of two identical halves each of which has one half of an internal post. When joined together to make the float, the internal post is fully formed and extends from one end of the float to the other. One magnetic element is slid over the post during manufacture and is free to slide from one end of the float to the other. Due to the symmetrical nature of the float and the freedom of movement of the internal magnetic element on the post, the float may be inserted into the fluid container without regard to which direction it faces thus lowering manufacturing costs. Flow seals are provided to completely shut off flow when the float is seated.

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A magnetic automatic stop valve formed in a container of a medical fluid administration system has one magnetic element located in a float and another magnetic element located proximate a valve seat. As the fluid level in the container decreases, the magnetic field established between the float and

A magnetic automatic stop valve formed in a container of a medical fluid administration system has one magnetic element located in a float and another magnetic element located proximate a valve seat. As the fluid level in the container decreases, the magnetic field established between the float and the valve seat eventually overcomes the buoyancy of the float in the fluid and attracts the float into the valve seat at which position the flow of fluid from the container is stopped. The float is formed of two identical halves each of which has one half of an internal post. When joined together to make the float, the internal post is fully formed and extends from one end of the float to the other. One magnetic element is slid over the post during manufacture and is free to slide from one end of the float to the other. Due to the symmetrical nature of the float and the freedom of movement of the internal magnetic element on the post, the float may be inserted into the fluid container without regard to which direction it faces thus lowering manufacturing costs. Flow seals are provided to completely shut off flow when the float is seated. 296; US-5020469, 19910600, Boissevain et al., 118/067; US-5163365, 19921100, Taylor, 100/038; US-5445071, 19950800, Winheim, 100/038; US-5915294, 19990600, Nyberg, 100/038 said bypass valve allowing a portion of water leaving said primary heat exchanger to pass through said bypass valve and reenter said primary heat exchanger; a second sensor providing a second signal representative of a temperature of said water entering said primary heat exchanger; means for defining a control range having a first portion and a second portion; means for controlling a position of said bypass valve in said first portion; and means for controlling said variable firing rate in said second portion when said boiler or water heater is operating at a reduced firing rate based on said demand for heat and an increase in firing rate is needed so as to maintain a water temperature above said first temperature. 12. The control system of claim 11 wherein said means for predicting a position of said bypass valve comprises means for processing said periodic corrective signals to determine incremental changes in said position. 13. The control system of claim 12 wherein a predicted position of said bypass valve may exceed 100 percent. 14. The control system of claim 11 wherein said bypass valve comprises an actuator and said means for controlling comprise periodic corrective signals to said actuator. 15. The control system of claim 14 wherein said bypass valve comprises a butterfly valve and an actuator. 16. The control system of claim 15 wherein said means for controlling said bypass valve comprises a derivative control mode. 17. The control system of claim 11 wherein said means for controlling said variable firing rate comprises: means for predicting a position of said bypass valve; means for selectively controlling said variable firing rate from said demand for heat or from a predicted position of said bypass valve. 18. The control system of claim 11 wherein a predicted position of said bypass valve may exceed 100 percent. 19. A method of control for a boiler or water heater having a variable firing rate, a primary heat exchanger, a secondary heat exchanger, and a bypass valve for allowing a portion of water leaving said primary heat exchanger to pass through said bypass valve and reenter said primary heat exchanger, said method comprising: periodically measuring a temperature of water entering said primary heat exchanger; comparing said temperature to a set point temperature; calculating a temperature error and a temperature error rate; issuing corrective signals to said bypass valve; accumulating said corrective signals to establish a location within a defined control range; apportioning said defined control range into a first portion and a second portion; controlling a physical position of said bypass valve within said first portion; and controlling said variable firing rate within said second portion. 20. The method of claim 19 wherein said accumulating said corrective signals to establish a location within a defined control range comprises predicting a position of said bypass valve wherein said predicted position may exceed a 100% open position. 21. The method of claim 19 wherein said bypass valve comprises a butterfly valve and a floating control actuator. 22. The method of claim 19 wherein said bypass valve comprises a three way valve. 23. The method of claim 19 wherein said controlling said variable firing rate within said second portion comprises selecting a control signal representative of heating demand or a control signal representative of said temperature of water entering said primary heat exchanger. e linkage. 2. The engine as in claim 1 wherein the hub has a flywheel attached thereto which flywheel having circumferentially a plurality of gear teeth for mating with a starter motor gear drive mechanism and the starter motor attached to the none of the engine.