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Piping the Solar Tank with Integrated Back-up as a One Tank System
Use 3/4” copper pipe for plumbing the tanks. To prevent heat loss through the copper tubing, insulate all
tubing with at least 1/2” wall tube insulation. This should include the cold water feed to the solar storage tank
up to 6 feet from the tank. A check valve should be installed on the cold water feed line to the mixing valve to
prevent hot water migration into the cold water piping.
The solar tank should include valves and piping for service.
A domestic hot water expansion tank can be installed on the cold water feed to the tanks. The expansion tank
should be installed downstream from a back flow preventer, for cold water feed to the tanks.
Service Valves and Instructions for Emergency
To isolate or service the hot water system in an emergency, turn system isolation valve #1 off.
To leave the system in an unoccupied house when hot water will not be drawn, the solar system should be
drained of antifreeze and the controller turned to “off” or unplugged. You may also turn the system isolation
valve #1 off if no hot water flow to the fixtures is desired.
