A modular liquid heating assembly includes a plurality of liquid delivery modules in series. The liquid delivery modules each include a module body having an inlet fitting, an outlet fitting, and a plurality of vessel coupling ports. The vessel coupling ports each include inflow and outflow orifices. The inlet and outlet fittings and the plurality of vessel coupling ports are in serial communication with each other through respective inflow and outflow orifices of the plurality of vessel coupling ports. At least one of the liquid delivery modules are configured for coupling with an inflow liquid line coupled with a liquid reservoir. Similarly at least one of the liquid delivery modules are configured for coupling with an outflow liquid line coupled with the liquid reservoir.

A PTC (Positive Temperature Coefficient) heater for liquid heating may include: a heat conductor; a PTC heating assembly; and water pipe assembly. The heat conductor may have a first accommodating duct and a second accommodating duct. The PTC heating assembly at least partially is disposed in the first accommodating duct; moreover, the water pipe assembly at least partially is disposed in the second accommodating duct, with an outer surface of the water pipe assembly at least partially abutting against an inner surface of the second accommodating duct. The PTC liquid heating tube of the present disclosure can achieve a better corrosion resistance and greatly extend the service life of the PTC heater as well as prevent electric leakage accidents. Furthermore, the PTC heater of the present disclosure will have a simple structure and low costs for being convenient to assemble, especially in the replacement of the water pipes for maintaining the PTC heater in future.

Disclosed in the present invention is a water circulation pipeline, comprising: an interface pipeline, the interface pipeline comprising a first pipeline and a second pipeline, one of the first pipeline and the second pipeline being provided with water inlets, and the other being provided with a water outlet, the water inlets and the water outlet being used for being connected to a water pool body, the second pipeline being nested in the first pipeline; and a pipeline body having a third pipeline, a first port of the third pipeline being in communication with the first pipeline, and a second port of the third pipeline being in communication with the second pipeline. The present invention can reduce the volumes of the water circulation pipeline and a control box. Also disclosed in the present invention are a control box and a massage water pool.

Swimming pool or spa gas heaters, cabinets, water header manifolds, and heat exchangers include: gas heaters having an air gap between a cabinet and combustion chamber to reduce heat transfer to sides of the cabinet; gas heaters having a user interface that is repositionable on a top panel; gas heater cabinets including a removable top panel that can be hung on a side panel; gas heaters having a built-in dual junction box; gas heaters having a top-accessible igniter and burner that are interlocked to maintain positioning thereof; adaptable water manifolds including connectable inlet and outlet fittings that adjust effective inlet and outlet positions; heat exchangers having a plurality of tube-and-fin subassemblies arranged in a semi-circular configuration; and water manifolds including internal cartridges that divide the water manifold into a plurality of chambers for improved circulation through a heat exchanger.

A managed water system can include a first body of water contained in a vessel. The managed water system can also include at least one sensor device that measures at least one parameter associated with the first body of water. The managed water system can further include a circulation system that circulates the body of water relative to the vessel. The managed water system can also include a controller communicably coupled to the at least one sensor device and the circulation system. The controller can control the circulation system, and receive measurements of the at least one parameter made by the at least one sensor device. The controller can also evaluate the measurements using multiple algorithms, and communicate a result of evaluating the measurements.

A portable solar powered pool heater comprising a housing, a hose, a controller, a solar panel and at least one leg having a first position for supporting the housing above a surface, and a second position disposed inside of the housing. This heater can include a hinge, wherein the leg comprises a leg that is coupled to the housing via the hinge. In one embodiment the leg comprises a telescoping leg having a first leg, and a second leg wherein said second leg is telescoping inside of the first leg.

A heat pump pool heater (HPPH) system is disclosed which may include a heat pump, a water temperature sensor, one or more evaporator sensors, and one or more supplemental heat sources. The HPPH system can determine that frost is forming on an evaporator coil and can transition from a normal pool water heating mode to a defrost mode to remove frost from the evaporator coil. During the defrost mode, the HPPH system can operate the one or more supplemental heat sources to provide heat to the pool water.

Embodiments of the invention provide a heater including a housing, a first tankless heater, a second tankless heater, a first and second flow directing elements, the first flow directing element in communication with the first tankless heater and the second flow directing element and the second flow directing element in communication with the second tankless heater, and a controller in communication with the first and second tankless heaters and the first and second flow directing elements, the controller configured to control the first and second flow directing elements to control flow to one or both of the first and second tankless heaters.

A device, system, and a method are provided for notifying a user to replace a sacrificial anode in a pool or spa system. The device is provided in the form of a body defining a cavity, a sacrificial anode, and a sensor. The sacrificial anode substantially surrounds the cavity when the sacrificial anode is coupled to the body. The sensor is at least partially received into the cavity and is in communication with a pool automation system. The sensor is designed to transmit a signal to the pool automation system when the sensor detects water within the cavity. The signal is processed by the pool automation system, and the pool automation system may then transmit a notification to a user that the sacrificial anode is depleted.

An inflatable spa is disclosed having improved strength. A water cavity of the inflatable spa may receive massaging air bubbles and/or jetted water.