Swimming pool chlorine blues

Nov 1, 2007 by

The case of the month concerns a residential in-ground swimming pool. On the day of a pool party for his kids, the insured accidentally spilled 5 gallons of dry chlorine powder into his pool. For those of us who are not familiar with pool maintenance procedures, 2 to 3 cups per 50,000 liters added twice weekly during the hot swimming season would be a ballpark measure to achieve the goal of 2 ppm, all other things being equal. The pool was not immediately drained, nor were any countermeasures taken that would have neutralized the chlorine.

Three weeks later, the insured turned in a claim to his insurance company that his 5-year-old pool heater was beginning to leak. Generally pool plumbing is PVC and should not be affected. GEI was assigned to investigate.
Our expert inspected the failed pool heater as the insured’s pool maintenance company was replacing it. The pool heater water leak occurred in the copper tubing that the water flowed through in the heat exchanger. Corrosion damage was the cause of the water leak. Excessive chlorine in the pool water is highly corrosive to copper and can cause a failure of this type. Conversations with the insured and his wife convinced the expert that the accidental spill of chlorine did occur as they described. The timing of the chlorine spill was consistent with a cause and effect relationship between the spill and the leak. The pool system piping and most of the parts were plastic and would not suffer failure from the excessive chlorine.

Our expert also observed an unrelated piping issue. There was a pipe penetrating the cement slab that was in direct contact with the slab. The pipe should have been routed through a protective sleeve or foam gasket. This was a construction error/oversight that would eventually lead to a piping failure in the future.

Our expert advised the homeowners to immediately correct the excessive chlorine and correct the PH and test the water weekly. They agreed to do this.

Approximately three months after the chlorine spill, the insured discovered that his Aqua Rite salt chlorine generator was not functioning properly. Again we were asked for help.

The function of the salt chlorine generator is to convert salt into chlorine. The original maintenance company examined the cell and advised the insured to clean the cell with an acid mixture. The insured did not think the cleaning worked and made an appointment with a different pool maintenance company to check it.

Our expert also checked it. The crystalline deposits that the insured observed on the cell indicated mineral deposits. This was a normal maintenance issue with this part. The normally occurring minerals in the water caused it. The remedy was cleaning the part. Excessive chlorine in the pool would not harm the salt chlorine generator system. Normal maintenance dictates that the cell should be inspected every three months and cleaning may be required at that time. The useful life of the cell was about four years. If the cell had failed then the likely cause was old age. To quote from the manual, “The electrolytic cell has a self-cleaning feature incorporated into the electronic control’s logic. In most cases this self-cleaning action will keep the cell working at optimum efficiency. In areas where water is hard (high mineral content) and in pools where the water chemistry has been allowed to get ‘out of balance’, the cell may require periodic cleaning.”

The general cleaning method was a vigorous spray by a high-pressure garden hose. When scaling was severe, then a soak for a few minutes in a 4 to 1 solution of muriatic acid and water, followed by a vigorous rinse by the garden hose was recommended. While the failure of the heat exchanger was related to the chlorine spill, the chlorine generator was not.

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