TM 10-4610-232-12
CAUTION
If the hypochlorite pump is allowed to run without liquid, damage will occur to the pump.
(10)
Open hypochlorite backwash pump priming valve (17) until hypochlorite is seen. Then close valve. Make sure
hypochlorite level drops about 1/2 gallon per minute during backwash.
(11)
Wait about one minute and 36 seconds until the feed water booster pump comes on. Adjust feed valve (9) to obtain a
flow rate at flowmeter (5) according to water temperature gage (18) as shown on Table 2-25. If media filter outlet
pressure is more than 30 psig, decrease flow rate slightly until it is not over 30.
(12)
Wait about ten minutes. When the final backwash step begins to take water from the clean/flush tank (19) (one minute
and 30 seconds), refer to Table 2-25 and readjust feed valve as necessary.
(13)
When the horn sounds, indicating backwash is complete, return to normal operation as described below.
(a)
Set OPERATION MODE switch (10) to FILTER NORMAL.
Table 2-25. Backwash Flow Rate
Water Temperature
Feed Flowmeter
32 to 40F (0-70C)
70 gpm (265 I/min)
40 to 45F (4-70C)
75 gpm (284 I/min)
45 to 50F (7-10C)
80 gpm (303 I/min)
50 to 55F (10-13C)
90 gpm (341 I/min)
55 to 60F (13-16C)
100 gpm (379 I/min)
60 to 65F (16-18C)
105 gpm (398 I/min)
65 to 70F (18-21C)
110 gpm (417 I/min)
70 to 75F (21-24C)
115 gpm (436 I/min)
over 75F (24C)
120 gpm (455 I/min)
(b)
Push INITIATE (11).
(c)
Push SYSTEM RESET (12).
NOTE
ALARM SILENCE pushbutton (20) is not operative at this time.
d.
Return to Normal Operation/Stage 5 Backwash.
(1)
Close cartridge filter block valve (21).
(2)
Partially open feed valve (9).
(3)
Push MEDIA FILTER FORWARD FLUSH pushbutton (22).
(4)
Push RAW WATER PUMP START (23).
(5)
Push CHEMICAL PUMP START (25).
(6)
When the MEDIA INLET/OUTLET PRESSURE gage (2) reads steady, push BOOSTER PUMP START (26) and slowly
close feed valve (9) until flowmeter (5) reads 100 gpm.
(7)
Open media filter vent valve (15). Close when water is seen at drain (24).
(8)
Hold steady for 10 minutes to repack the media bed.
(9)
Open cartridge filter block valve (21).
(10)
Fully open feed valve (9).
(10.1)
Open system pressure control valve (3).
(11)
Push MEDIA FILTER FORWARD FLUSH pushbutton (22).
(12)
Open cartridge filter vent (27). Close when water is seen.
(13)
Observe CARTRIDGE INLET/OUTLET PRESSURE gage (28). Reading should come up to 50 psig (345 kPa) minimum
on the red needle and all flags on media level gage are orange.
2-94 Change 12
