TL;DR

Carryover means liquid water is leaving the tower with the exhaust air. Check fan speed against design, inspect drift eliminators for damage, and verify the circulating water flow rate is not above the design maximum.

What you might see

wet surfaces and puddles downwind of the tower
makeup water consumption above expected evaporation
scale deposits on nearby structures
visible water droplets exiting the fan stack

Likely causes

Tap to mark as ruled out

Excessive fan speed or airflow rate above the drift eliminator design velocity
Damaged or improperly seated drift eliminator panels allowing bypass
Overcirculation: water flow rate exceeding the tower design maximum
High wind conditions that defeat the eliminator at certain wind directions

Required tools

Tachometer (contact or non-contact)
LOTO kit
Flow meter or pump curve data

Safety first

Lock out the fan before inspecting drift eliminators inside the tower.
Carry-over water contains concentrated cooling tower chemistry. Keep personnel out of the downwind zone during diagnosis.

Procedure

6 steps · ~45 min

1
Measure the fan RPM with a tachometer and compare to the design value on the Marley nameplate. Reduce fan speed if above design.
2
Lock out the fan and inspect the drift eliminator panels for damage or gaps (see the excessive-drift procedure on this machine).[1]
3
Measure the circulating water flow rate and compare to the design GPM on the tower datasheet. Reduce flow if above design maximum.
4
Check that all distribution nozzles are oriented correctly and not spraying into the airstream above the fill.[1]
5
If high winds are the trigger, check whether a wind shield or louver panel is specified for this installation. Install if missing.
6
After corrections, observe the discharge plume from multiple angles in normal operating conditions. Droplets should not be visible more than 1 meter from the discharge.

Sources

Marley NC Cooling Tower User Manual, Marley Cooling (SPX Cooling Technologies)
Marley NC Cooling Tower Installation, Operation and Maintenance manual, drift and carryover troubleshooting (general)
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