Cooling Tower Makeup Water Float Valve

A cooling tower makeup water float valve is a mechanical level-control valve that automatically adds makeup water to the cooling tower basin to keep the water level within the normal operating range.

What the Makeup Water Float Valve Does

* Opens when basin level drops (evaporation, drift, blowdown)

* Allows fresh makeup water to enter

* Closes when the preset level is reached

* Protects condenser water pumps from cavitation and dry running

How Cooling Tower Makeup Water Float Valve Works

1. Basin water level falls

2. Float ball drops with the water level

3. Valve opens and admits makeup water

4. Water level rises

5. Float lifts → valve closes

✔ No electricity required

✔ Simple and reliable

Common Types Of Cooling Tower Makeup Water Float Valve

1️⃣ Brass Float Valve

* Most widely used

* Suitable for normal city water

* Economical

2️⃣ Stainless Steel Float Valve (SS304 / SS316)

* For corrosive or high-TDS water

* Longer service life

* Used in industrial cooling towers

 3️⃣ Plastic Float Valve (PVC / ABS)

* Corrosion-free

* Used in FRP cooling towers

* Light-duty applications

Typical Sizes & Ratings OF Cooling Tower Makeup Water Float Valve

Item	Typical Range
Connection size	¾″ – 2″ (DN20–DN50)
Working pressure	2 – 6 bar
Makeup flow	5 – 50 m³/h
Max temperature	≤ 60 °C

Installation Location Of Cooling Tower Makeup Water Float Valve

* Mounted on the side wall of the cooling tower basin

* Connected to:

 * City water

 * Softened water

 * RO makeup water

* Float level set at normal operating water level

Makeup Float Valve vs Electronic Level Control

Float Valve	Electronic Valve
Mechanical	Sensor + solenoid
Low cost	Higher accuracy
No power needed	Requires power
Small–medium towers	Large / critical plants

Common Problems & Fixes Of Cooling Tower Makeup Water Float Valve

* Overflow → valve stuck open → clean or replace

* Low basin level → float jammed → adjust float arm

* Water hammer → high pressure → install PRV

* Scaling → poor water quality → improve treatment

Best Practices

✔ Install a strainer before the valve

✔ Add an isolation valve for maintenance

✔ Keep makeup pressure < 6 bar

✔ Set float level above pump suction

✔ Inspect regularly for free float movement