9
operation
The water conditions during initial fluid cooler operation are crucial in pre-
venting premature corrosion of galvanized steel (white rust). For at least
the first eight weeks of operation, pH should be controlled between 6.5
and 8.0 with hardness and alkalinity levels between 100 and 300 ppm
(expressed as CaCO
3
).
2. Do NOT attempt any service unless the fan motor is locked out.
3. Remove any and all accumulated debris from fluid cooler. Pay particular
attention to inside areas of collection water basin, distribution water
system, louvers and drift eliminators. Make sure that recirculating water
suction screens are clear and properly installed.
4. Fill the collection basin water system to a level approximately
1
⁄
8
" below
the lip of the overflow.
5. Start your pump(s) and check for proper rotation as indicated by the ar-
row on the pump cover, observe system operation. A certain amount of
“pump-down” of the basin water level will occur before water completes
the circuit and begins to fall from the coil(s). The water makeup valve is
factory set to keep the water level in the basin at approximately 7" of depth
during operation. The amount of initial pump-down may be insufficient to
open the float valve. However, its operation can be checked by pressing
down on the operating lever to which the stem of the float valve is attached.
The float valve is set so that the water level after pump start-up is deep
enough to assure positive suction, but not overflow at pump shutdown.
6. Open the valve on the fluid cooler bleed line and adjust bleed to the
recommended rate. See the
Water Quality and Blowdown
section.
7. Continue pump operation for about 15 minutes, after which it is recom-
mended that the water system be drained, flushed and refilled.
8. While operating the recirculating water pump(s) and prior to operating the
fluid cooler fan(s), execute one of the two alternative biocidal treatment
programs described in the following:
• Resume treatment with the biocide which had been used prior to shut-
down. Utilize the services of the water treatment supplier. Maintain 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 ppm free
chlorine residual at a pH of 7.0 to 7.6. The chlorine residual must be
held at 4 to 5 ppm for six hours, measurable with standard commercial
water test kits.
