Abstract: A hot water heating system, and kit for installing such a system, that utilizes male and female union connections for all main heating system components allows the system to be completely installed using only two ordinary wrenches. The system includes a first isolator valve, a flow control valve, a circulator and a second isolator valve. Each of these components is equipped with one male union type connection on one side of the component and one female union type connection on the other side. The system may be an installed system or may entail a kit of parts for installation.