A water path control valve structure for flushing the toilet lid, which is divided into upper and lower valve parts, including a valve body, a linkage valve core and a sealing component. The sealing component is installed on the linkage valve core, and the linkage valve core is arranged in the hollow valve body and one end of the linkage valve core extends out of the valve body. The linkage valve core includes an upper valve core and a lower valve core arranged coaxially, and one end of the upper valve core extends out of the valve body. The upper and lower valve cores are respectively installed with the sealing member.

A water path control valve structure for flushing the toilet lid, which is divided into upper and lower valve parts, including a valve body, a linkage valve core and a sealing component. The sealing component is installed on the linkage valve core, and the linkage valve core is arranged in the hollow valve body and one end of the linkage valve core extends out of the valve body. The linkage valve core includes an upper valve core and a lower valve core arranged coaxially, and one end of the upper valve core extends out of the valve body. The upper and lower valve cores are respectively installed with the sealing member.

An aspect includes an offset parallel valve system that includes a first valve body and a first valve disc operably disposed within the first valve body. The offset parallel valve system also includes a second valve body in parallel with the first valve body and a second valve disc operably disposed within the second valve body, where the second valve disc is laterally offset from the first valve disc. A linkage system is operably coupled to the first valve disc and the second valve disc. The linkage system includes an armature coupled to a grooved linkage member having a first groove and a second groove. The first groove delays movement of the second valve disc as the first valve disc rotates, and the second groove controls a rotation angle of the second valve disc.

An aspect includes an offset parallel valve system that includes a first valve body and a first valve disc operably disposed within the first valve body. The offset parallel valve system also includes a second valve body in parallel with the first valve body and a second valve disc operably disposed within the second valve body, where the second valve disc is laterally offset from the first valve disc. A linkage system is operably coupled to the first valve disc and the second valve disc. The linkage system includes an armature coupled to a grooved linkage member having a first groove and a second groove. The first groove delays movement of the second valve disc as the first valve disc rotates, and the second groove controls a rotation angle of the second valve disc.

A dual fuel heating system can be used in a gas appliance. A dual fuel heating system can have a fuel selector valve for selecting between a first fuel and a second fuel different from the first. The dual fuel heating system can include a regulator unit configured to regulate the pressure of the two different fuels. The selector valve determines which flow path for which fuel is open and which is closed.