TM 51930-209-14& P-4
For an alternate method of producing chlorine solution to eliminate initial buildup time, add 10 gallons of
commercial hypochlorite solution (Clorox or other liquid chlorine bleach) to holding tank as follows:
Open cap on Y-connection on top of holding tank.
Add 1 gallon of commercial hypochlorite solution (bleach) for every 9 gallons of water in holding tank.
Close cap on Y-connection of holding tank.
Turn function switch on control cabinet (Figure 3-5) to OFF/RESET to stop recirculation of holding
3-7 Chlorination unit descaling. Perform this procedure when an excess of white mineral scale shows on the
chlorination unit cells (anodes), when there is a decrease in flow rate to holding tank as shown on makeup flowmeter
(Figure 3-1 ), or when there is an absence of solution at top of the cells. When any of these conditions are observed,
excessive scale build-up or low flow is occurring. Flush and descale unit. Flushing procedure uses water from
seawater system to flush chlorination unit. Holding tank continues to supply chlorine to product water during
descaling and flushing operations.
If EMS alarms are activated during descaling procedure, acknowledge
alarms according to paragraph 3-4, step p.
3-7.1 Initial flushing with seawater
Make sure seawater system is operating and providing seawater to chlorination system through seawater
valve SW47 or SW48.
Turn alarm ON/OFF switch on control cabinet (Figure 3-5) to OFF.
Turn function switch on control cabinet (Figure 3-5) to OFF/RESET.
Position chlorination unit valves as indicated below:
Position valve CU4 halfway between positions A and C to reduce flow through system.
Turn brine pump ON/OFF switch inside control cabinet (Figure 3-5) to OFF.
Turn cooling water flowmeter, OFF by closing valve at bottom of flowmeter (Figure 3-1).
Turn makeup water flowmeter OFF by closing valve at bottom of flowmeter (Figure 3-1).
Turn function switch on control cabinet (Figure 3-5) to FLUSH.
Allow seawater to flow through chlorination unit for 5 minutes, then turn function switch on control cabinetto
Open chlorination valve CU9 to allow chlorination unit to drain. If sump appears to be overfilling, partially
close valve CU9 to reduce drain flow to sump.
After chlorination unit has drained, close valves CU8 and CU9 and turn valve CU5 to position C (OFF).
Flush unit with acid according to paragraph 3-7.2.
3-7.2 Flushing with acid
3-7.2.1 Acid tank preparation
Wear rubber gloves, safety goggles or faceshield, and chemical dust mask
when working with acid cryst als and acid solution.