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 low water sensor testing apparatus consisting of a 2 piece threaded steel ball valve unit with spring loaded handle connected at one end cavity portion thereof to initial piping emanating from a hot water boiler and connected at the second end cavity portion thereof to an equivalent adapter unit in turn connected to the first end segment of an E-shaped piping unit having its first stem portion connected to a ball valve unit via another adapter unit, its second stem portion connected via yet another adapter unit to a low water sensor unit and, with the second end segment of the E-shaped piping unit being connected to another equivalent adapter unit in turn connected to the first end cavity portion of a three way purge valve unit being connectable within the second cavity end portion thereof to outflow piping leading to a structure's heating system.

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 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.

A water heater and thermostatic control device for a lavatory faucet includes a hot water tank having a reservoir and a heating element disposed within the reservoir, the heating element heats ambient temperature water received by the reservoir to produce hot water, a thermal mixing valve configured to mix hot water received from the hot water tank with ambient temperature water to produce mixed temperature water. The water heater and thermostatic control device also includes a shut off valve configured to permit flow of mixed temperature water to the lavatory faucet, wherein the shut off valve includes a diaphragm and an armature assembly, and wherein the diaphragm is configured to permit air to bleed or vent through the shut off valve when the mixed temperature water is not imparting pressure on the diaphragm.

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. Analyses 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 low water sensor testing apparatus consisting of a 2 piece threaded steel ball valve unit with spring loaded handle connected at one end cavity portion thereof to initial piping emanating from a hot water boiler and connected at the second end cavity portion thereof to an equivalent adapter unit in turn connected to the first end segment of an E-shaped piping unit having its first stem portion connected to a ball valve unit via another adapter unit, its second stem portion connected via yet another adapter unit to a low water sensor unit and, with the second end segment of the E-shaped piping unit being connected to another equivalent adapter unit in turn connected to the first end cavity portion of a three way purge valve unit being connectable within the second cavity end portion thereof to outflow piping leading to a structure's heating system.

An expansion tank which comprises a tank having a predetermined volume capacity; an expandable elastomeric bladder in the tank, partitioning tank volume into a liquid-containing portion for holding liquid and a gas-containing portion for holding a gas under a pressure that defines a normal pressurized gas volume when the liquid-containing portion holds a predetermined liquid volume; and a proximity sensor mounted to the tank at the gas-containing portion thereof and adapted to emit an alarm signal when volume of the gas-containing portion is reduced.

A heat recovery system arranged to heat water includes at least one heat exchanger (9) arranged to heat water by heat exchange with waste heat. A storage reservoir (11) is arranged to store water heated by the heat exchanger (9). The heat exchanger (9) is switchable between a first mode of operation in which water is circulated by a pump (12) in a circuit that includes the storage reservoir (11) and the heat exchanger (9), and a second mode of operation in which water is circulated by the pump (12) in a circuit that by-passes the heat exchanger (9). Heated water of at least a desired minimum temperature can be supplied to at least one outlet during both the first and second modes of operation.