Water Distribution And Heat Transfer Section; Water Level Control - BAC PCT Series Operation & Maintenance Manual

Cooling towers

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Table Of Contents

Table of Contents

Water Level Control

There are two types of water level controls used on BAC cooling towers:

• Mechanical make-up valve assembly

• Optional electric water level control package

Mechanical Make-up Valve Assembly

A float-operated mechanical water make-up assembly is furnished

as standard equipment on the cooling tower. The standard make-up

assembly consists of a corrosion resistant make-up valve connected to

a float arm assembly actuated by a polystyrene-filled plastic float. The

float is mounted on an all-thread rod held in place by wing nuts. The

cold water basin operating water level can be adjusted by repositioning

the float and all-thread rod using the wing nuts provided.

• Inspect the make-up valve assembly monthly and adjust if necessary.

• Inspect the valve annually for leakage. Replace the valve seat if

necessary.

• Maintain the make-up water supply pressure between 100 and 350

kPa for proper operation. BAC recommends a surge protector

(provided by others) for pressures over 350 kPa.

• Set the initial basin water level by adjusting the wing nuts so

that the make-up valve is completely closed when the water level

in the cold water basin is at the operating level.

• With the design thermal load and the average water pressure

(100 to 350 kPa) at the valve, the above setting will produce

operating water levels as stated in Table 1 on Page 9.

• If the thermal load is less than the design load at the time of

unit start-up, the procedure may produce operating levels greater

than those shown in Table 1. If operating levels are higher than

specified, readjust the float in order to attain the recommended

operating level.

• Closely monitor the water level in the cold water basin and adjust

the level if necessary during the first 24 hours of operation.

• Operating at the recommended water level will ensure that the unit

basin contains sufficient water volume to prevent air entrainment in

the circulating pump during system start-up and provides sufficient

excess basin capacity to accept the total system pulldown volume.

Detailed Component

Maintenance Procedures

Louvres and Eliminators