The plumbing of a solar water heater system is divided into 2 parts, the glycol system which circulates through the roof top collectors, and the potable water system which includes the solar hot water storage tank, the home water heater, and the safety valves and expansion tank.
The glycol loop consists of 2 pipes running to the roof to allow a pump to circulate the fluid and bring the heat to the water storage tank. A heat exchanger separates the glycol loop from the potable water in the storage tank.
The plumbing in the “tank room” will contain a number of devices, a pump or pumps, temperature gauges, a pressure gauge, a flow meter, a controller, and ports to insert and check the glycol. On the potable side, the anti-scald valve and another temperature gauge will be plumbed in.