A switch assembly features an automatic switch and an electronic circuit board. The automatic switch has a common contact and a normally open switch contact to short when a boiler has sufficient water, and has the common contact and a normally closed switch contact to short when the boiler has a low water level. The electronic circuit board has a signal processor, a reset switch, and a low water status LED for providing a status indication of a low water condition that remains ON even if the water level has risen unless the reset switch is reset. The signal processor couples to the common contact, the normally closed switch contact and the normally open switch contact, senses signaling containing the status of the common contact, the normally closed switch contact and the normally open switch contact, provides corresponding signaling to turn ON the low water status LED when the water level is low, and responds to a reset switch signal and turn OFF the low water status LED.

An air heating apparatus according to the present disclosure includes an expansion tank that stores water, a water heater that receives heat from a combustion gas generated by a combustion reaction and heats the water, a heating heat exchanger that receives the water heated by the water heater and exchanges the heat with air to be discharged for heating, a fan that delivers the air to the heating heat exchanger, and a steam supply flow path that supplies steam in the expansion tank to the fan.

A water heating system can include a water heater having a tank, and a first temperature sensor disposed toward a top end of the tank to measure a first temperature and a second temperature sensor disposed toward a bottom end of the tank to measure a second temperature. The water heating system can further include a controller communicably coupled to the first temperature sensor and the second temperature sensor, where the controller determines an amount of heated water in the tank based on a plurality of algorithms and measurements made by the first and second temperature sensors. The plurality of algorithms solves for at least one calculated temperature for at least one point between a first location of the first temperature sensor and a second location of the second temperature sensor, where the at least one calculated temperature is used to determine the amount of heated water in the tank.

A coolant heating device for a vehicle includes: a housing storing coolant therein and having a sheath heater therein; an upper space part protruding upwards from a top surface of the housing and having an inner space via which an inner space of the housing communicates with the upper space part; a water-level-sensing part disposed inside the upper space part to sense a level of coolant in the housing; and a controller for controlling operation of the sheath heater based on the level of coolant sensed by the water-level-sensing part.

A switch assembly includes an automatic type 11 switch having 1 and 2 contacts and 3 and 4 contacts with the 2 and 3 contacts being shorted together, configured to respond to a water level of a boiler, short the 1 and 2 contacts when the water level is high, short the 3 and 4 contacts when the water level is low; and an electronic circuit board having a processor configured to sense signaling containing information about the 1, 2/3 and 4 contacts, and provide control signaling containing information about the water level of the boiler. The electronic circuit board also includes a relay configured to respond to the control signaling, and turn the relay on/off.

Mobile water heating systems for producing hot water are disclosed herein. In one embodiment, a mobile water heating system includes a water heater having an oval-cylindrical shape. The water heater includes a shell, a lid and a water reservoir having a screen. A first heating coil and a second heating coil can extend between the screen and a first cone and a second cone, respectively. A first burner and a second burner can be configured to mix and combust fuel and air and direct the resulting flames through the heating coils. Pall rings can at least partially fill an interior volume of the water heater and the combustion of the fuel and air can heat the heating coils and the pall rings. Water can be heated by being directed through the heating coils and through a water manifold positioned to spray water on the pall rings.

A hydronic heating system that may depend on pressure in the system for smooth operation. The pressure may be monitored. Pressure in the system may indicate health of the heating system. Certain pressures or variations of pressures may indicate one or more conditions in the system which may be good or adverse. An example of an adverse condition may be leakage of fluid from the system. Analyzes of pressures detected in the heating system may be performed by a computer programmed to indicate conditions of the system that are reflected by the detected pressures.

A heating system including a thermal battery including an opening, a storage container configured to hold a first fluid therein, the opening configured to expose the first fluid to atmospheric pressure; and a fluid conductor disposed through the first fluid from an inlet point at the storage container to an outlet point at the storage container, the fluid conductor configured to receive a second fluid at a first temperature at the inlet point and to supply the second fluid at a second temperature higher than the first temperature.

A fluid transportation network (1) comprises a plurality of parallel zones (Z1, Z2), fed by a common supply line (L), with a regulating zone valve (V1, V2) in each zone (Z1, Z2) for regulating a flow of fluid (.sub.1, .sub.2) through the respective zone (Z1, Z2). A processing unit (RE) receives valve positions (pos.sub.1, pos.sub.2) of the regulating zone valves (V1, V2) and determines and sets an adjusted valve position for a line valve (VE) arranged in the supply line (L), depending on the valve positions (pos.sub.1, pos.sub.2) of the regulating zone valves (V1, V2). A processing unit (RE) further receives a measurement of a total flow of fluid (.sub.tot) through the supply line (L) and determines and sets adjusted valve positions for the regulating zone valves (V1, V2), depending on the measurement of the total flow of fluid (.sub.tot) through the supply line (L).

A combined water heater and thermostatic control device that combines the functionality of a water heater, thermostat and shut off valve, and may be installed in various aircraft lavatory applications to facilitate installation, consolidate functions, and reduce the probability of leaks. The combined device may include a water tank assembly, a torque motor valve and servo valve assembly, and a shut-off valve assembly. The combined device may also include a temperature control unit that senses water temperature in a water tank assembly and may activate a water heater.