Marley Aquatower 490A, User Manual, Page: 13 / 28

1
5. Make sure blowdown line is discharging water.
6. Depth of water in hot water basin should be uniform. If the basin overflows,
reduce the flow rate. Do not pump more water than design capacity.
7. Continue pump operation for about 15 minutes, after which it is rec-
ommended that the water system be drained, flushed, and refilled.
8. While operating the condensing water pump(s) and prior to operat-
ing the cooling tower fan, execute one of the two alternative biocidal
treatment programs described in the following:
• Resume treatment with the biocide which had been used prior to
shutdown. Utilize the services of the water treatment supplier. Main-
tain the maximum recommended biocide residual (for the specific
biocide) for a sufficient period of time (residual and time will vary with
the biocide) to bring the system under good biological control.
or
• Treat the system with sodium hypochlorite to a level of 4 to 5 mg/L
(ppm) free chlorine residual at a pH of 7.0 to 7.6. The chlorine re-
sidual must be held at 4 to 5 mg/L (ppm) for six hours, measurable
with standard commercial water test kits.
If the cooling tower has been in operation and then shut down for a
duration of time and not drained, perform one of the two previous
biocidal treatment programs directly to the cooling water storage
vessel (cooling tower sump, drain down tank, etc.) without circulat-
ing stagnant water over the cooling tower fill or operating the cooling
tower fan.
After biocidal pretreatment has been successfully completed, cooling
water may be circulated over the tower fill with the fan off.
When biocidal treatment has been maintained at a satisfactory level for
at least six hours, the fan may be turned on and the system returned
to service. Resume the standard water treatment program, including
biocidal treatment.
9. Check fan for free rotation and check oil level in bearing housing as
required (see maintenance instructions). Start motor and check di-
rection of rotation. Fan must rotate clockwise when viewed from the
fan discharge side. If the rotation is incorrect, change any two of the
three motor leads.
Do not allow the total motor acceleration time to exceed 30 seconds
per hour.
Operation
Note