Cooling Tower Trouble Shooting
Problem with cooling tower in any application are not only the inconvenience, but can also be contribute to loss of production.
An efficient industrial process or HVAC operation depends upon trouble free functioning of a cooling tower. By keeping a cooling tower in good working order, savings in time and energy can be made.
This fact sheet deals with the common cooling tower malfunctioning with probable cause and procedures for checking and correcting possible faults.
1. Cooling tower delivering high temperature
There can be several possible causes such as stopping of motor, increased water flow, lowering down the air flow, standstill of rotating sprinkler/uneven water distribution, choked fills, mixing of entering hot water with cold water in basin, the fan rotation in inverse direction.
Re-circulation of plume may also be a probable cause, when the hot saturated air (Plume) emitted from the discharge side of a cooling tower may be partially driven towards it’s inlet.
In order to fix the problem, we should get the motor repaired or replaced. Contacts of motor should be checked before sending it for repairing.
Water flow can be regulated by adjustment of valves or rectification in the pump. Similarly the airflow can be optimized by increasing the fan angles.
Uneven water distribution problem may be eliminated by cleaning of sprinkle head and branch pipes. Turn buckle/tension device should be tightened up for balanced rotation of sprinkler. Fills can be cleaned by suitable water treatment or may be replaced in case of deterioration.
Leakage should be rectified at mixing point of water inlet and cold water basin. Fan must rotate in clockwise direction while examined from arial view. This can be rectified by changing electric connection of motor/starter.
The cause of re-circulation are mainly basic geometry of cooling tower design, location of the surrounding buildings and structures, presence of any obstruction to the air flow upstream or downstream of the cooling tower, presence of any heat or moisture generating equipment in the vicinity of the cooling tower etc.
2. Raised motor temperature & current
Motor temperature is usually raised due to drop in voltage, excessive air flow, imbalanced fan and touching of rotor with the stator.
Voltage problem can be checked at the supply end. Airflow can be controlled by reducing fan blade angles. Fan can be sent to our works for dynamic balancing. Likewise the motor can be checked/repaired by the user or the motor manufacturer.
3. Reduced Water Flow
There may be several causes for the reduction of water flow in cooling tower, such as blocked/choked water distribution pipes, choked filter/strainer and insufficient pump size.
Sprinkler pipes/distribution pipes should be cleaned properly. Similarly the strainer/filter should also be cleaned. Pump may be replaced as per the designed parameters.
4. Excess water losses
This may be caused by the faster rotation of sprinkler, improper eliminator, broken end caps, over flowing of water from basin or higher angle of fan blades.
Rotation of sprinkler can be controlled by adjusting branch pipes. FRP/PVC eliminators should be properly placed and fixed in order to cover the water distribution system. Carry over losses can be controlled by adjusting the fan to the suitable angle. End caps should be replaced. Overflow problem can be controlled by adjusting the valve.
5.Noise and vibration
Loose fan mountings must be properly tightened by adequate fasteners and torque. Fan may be sent to us for dynamic/static balancing in case if the fan is imbalanced. Motor bearing problem may be solved by greasing or replacement.