cleaning is by using inhibited acid to clean coils or tubes through chemical action. Figure 7-18 shows the connections and the equipment for cleaning the condenser with an inhibited acid, both when the acid flows by gravity (view 1) and when forced circulation is used (view 2). When scale deposit is not great, gravity flow of the acid provides enough cleaning. When the deposit almost clogs the tubes, forced circulation should be used.

WARNING

Prevent chemical solution from splashing in your eyes and on your skin or clothing.

Equipment and connections for circulating inhibited acid through the condenser using gravity flow, as shown in figure 7-18, view 1, are as follows:

1. A rubber or plastic bucket for mixing solution. Do not use galvanized materials because prolonged contact with acid deteriorates such surfaces.

2. A crock or wooden bucket for catching the drainage residue.

3. One-inch steel pipe that is long enough to make the connections shown.

4. Fittings for l-inch steel pipe. The vent pipe shown should be installed at the higher connection of the condenser.

Equipment and connections for circulating inhibited acid through the condenser using forced circulation, as shown in figure 7-18, are as follows:

1. A pump suitable for this application. A centrifugal pump and a 1/2-horsepower motor is recommended (30 gallons per minute at 35-foot head capacity).

2. A nongalvanized metal tank, stone or porcelain crock, or wooden barrel with a capacity of about 50 gallons with ordinary bronze or copper screening to keep large pieces of scale or dirt from getting into the pump intakes.

3. One-inch pipe that is long enough to make the piping connections shown.

4. Fittings for l-inch steel globe valves. The vent pipe, as shown, should be installed at the higher connection of the condenser.

Handle the inhibited acid for cleaning condensers with the usual precautions observed when handling acids. It stains hands and clothing and attacks concrete and if an inhibitor is not present, it reacts with steel. Therefore, use every precaution to prevent spilling or splashing. When splashing might occur, cover the surfaces with burlap or boards. Gas produced during cleaning that escapes through the vent pipe is not harmfu but prevents any liquid or spray from being carried hrough with the gas. The basic formula should

Figure 7-18. - Cleaning water-cooled condensers with acid solution.