Читать книгу Solar Water Heating--Revised & Expanded Edition - Bob Ramlow - Страница 41

It is important that all the components within a solar loop are made of compatible materials. When different materials are mixed in a plumbing circuit, galvanic reactions can take place that speed up oxidation and deterioration of the components. We prefer to use brass, stainless steel or bronze pumps in the solar water heating system, both in the solar loop and for all potable water plumbing. Some installers choose to use a cast-iron pump on the solar loop because it is often significantly less expensive. Though this may lead to corrosion, if the pump is separated from the piping loop through pump flanges, the gaskets often provide enough separation to prolong their use. The impellers within the pump are almost always made of stainless steel or plastic, so they are not a problem. It is the pump housing that is critical.

Figure 4.5: Tube-in-shell heat exchanger