Isolate and drain the water side of the heat exchanger. Turn off the solar control, to
prevent the circulation of hot solar fluid.
Connect two hoses to the water inlet and outlet of the heat exchanger. Connect one
hose to the outlet of a small acid pump. (Little Giant Model 2E-NVDR is
appropriate.) Connect a third hose to the inlet of the acid pump.
As you might expect, even dilute solutions of descaling acid can injure
eyes and skin. Follow reasonable safety practices, including eye
protection and rubber gloves. Keep pure and diluted mixtures out of
the reach of children and animals. Be sure to flush descaled piping
and heat exchangers with plenty of fresh water before returning them
Follow the manufacturer's instructions to mix the descaling acid with water.
Generally, solutions should be a maximum of 7% by volume. Make enough to fill
the water passageways and still have at least two inches left in the bottom of a
Descaling a Heat
5.2 REPAIR PROCEDURES