Situation

One of APTech Group’s partners began treating systems at a large federal facility in January, 2008. At the time of start-up, the cooling towers and chillers were six months old. The commercial center had just replaced 2 x 800 ton chillers and a 300 ton chiller with two new 900 ton chillers and a 400 ton chiller. They also replaced the cooling towers with new stainless steel Marley cooling towers. After only six months of operation, the cooling tower fill had accumulated 1/4″ of scale in some areas (Photos 1, 2). So much scale had built-up inside the fill that it began to crumble and stack up at the bottom near the basin due to the weight (Photo 3). The basin of the tower, below the water line, and the cooling tower hot distribution decks were also very scaled (Photo 4).

Solution

It wasn’t until the following year that our partner was able to see the inside of the chillers.  They began using the OLC-STX in the beginning and then later switched to feeding the OLC-C from a solid feeder.

Results

They began seeing results almost immediately. Within a couple of months, the scale got thinner inside the fill. After about five months, the scale that had formed on the cooling tower basin had also started to become thin and even began flaking from the basin. After a little over one year the cooling tower fill was almost completely clean and the basin scale had gone from 1/4″ in thickness to eggshell-thin and flaking away (Photos 5, 6, & 7).

APTech’s partner was present when the chillers were opened for an annual inspection the following year. Although it was evident that the scale deposits were being removed, the two 900 ton chillers were still badly scaled. These two chillers alternate, so they are not always running. The 400 ton chiller is the most active. It is loaded almost constantly and is even used as the after-hours chiller. Our partner was pleased to see it completely clean when it was opened for PM and inspection. It looked amazing! Due to the 400 ton chiller’s percent load, the OLC-C was able to remove the deposits and scale build-up.

GSA was extremely impressed, to say the very least. Our partner has since been awarded 14 additional buildings due largely in part to the success we have had in with the towers and chillers at this commercial center. It has been over five years since the OLC product started being used at this facility. Although there are some small areas on the basin that still have thin scale present, the towers are in great shape.