Abstract: A water heating apparatus having structure for recovering sensible and latent heat from flue gases generated in a heater thereof and transferring the heat to water to be heated. The apparatus has a closed circuit for liquid, such as water, in which are positioned two heat exchangers. One of the heat exchangers is positioned in the heater of the apparatus for transferring heat from a burner of the heater to liquid in the closed circuit. The other heat exchanger is positioned in a water pass-through system to heat the water therein. The apparatus has an air pass-through system for carrying flue gases from the heater out an exhaust pipe. The flue gases travel through a third heat exchanger positioned in the water pass-through system whereby sensible and latent heat from the flue gases are transferred to water in the water pass-through system, further heating the water therein.

Abstract: A water heating apparatus having structure for recovering sensible and latent heat from flue gases generated in a heater thereof and transferring the heat to water to be heated. The apparatus has a closed circuit for liquid, such as water, in which are positioned two heat exchangers. One of the heat exchangers is positioned in the heater of the apparatus for transferring heat from a burner of the heater to liquid in the closed circuit. The other heat exchanger is positioned in a water pass-through system to heat the water therein. The apparatus has an air pass-through system for carrying flue gases from the heater out an exhaust pipe. The flue gases travel through a third heat exchanger positioned in the water pass-through system whereby sensible and latent heat from the flue gases are transferred to water in the water pass-through system, further heating the water therein.

Abstract: A heating system is provided with a closed circuit system for a first liquid, a pass-through system for a second liquid and a controller. The closed circuit system has a primary heater with a first heat exchanger, a second heat exchanger and a circulating pump. The primary heater has a burner for burning hydrocarbon fuel and has a first heat exchanger for transferring heat from combustion products of hydrocarbon fuel to the first liquid. The second heat exchanger allows transfer of heat from the first liquid heated in the first heat exchanger to the second liquid in the pass-through system. The closed systems also has an outlet pipe connecting an outlet of the first heat exchanger to an inlet of the second heat exchanger, and an inlet pipe connecting an inlet of the first heat exchanger to an outlet of the second heat exchanger. The pass-through system has a storage tank, a recirculating tube system with recirculating pump, a main second liquid supply, a withdrawal tube and a fast response temperature sensor.

Abstract: A system of daylight running lights utilizing the front turn signal lights of a vehicle incorporates a solenoid coil and a double pole single throw switch, such that when the coil is activated, both poles are closed. A connection from the ignition circuit to the coil is such that when the ignition circuit is at "run", power is available to said coil. The circuit is such as to prevent the coil from being grounded, thus de-activating the coil, whenever the turn signal switch is on, or whenever the headlight switch is on. When either of these conditions applies, the DPST switch is open. The coil is grounded and thus activated whenever the turn signal switch and the headlight switch are both off. The circuit is such that power can be fed through the DPST switch, when closed, to energize both signal lights simultaneously, thus providing daytime running lights.