Frost heaving occurs when the earth expands and contracts due to freezing and thawing. This process can cause the cleanout to be separated from the combo which connects it to the sewer line, even below the frost line. Moist, fine-grained soil at certain temperatures is most susceptible to frost heaving. To prevent this problem from occuring JEI applies a 6 mil plastic sleeve so the earth can not grab hold of the pipe and cause it to be disconnected. This in turn prevents rocks and other debris from falling into the sewer line and plugging it presenting problems for the customer.
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