Condensate contamination control continuously monitors returning condensate with a conductivity sensor and automatically dumps contaminated condensate before it reaches the feed tank. Plants can recover as much condensate as possible – saving fuel, water and chemicals – while protecting the boiler from foaming, scaling and corrosion. ISE supplies complete sensor, controller and diverter-valve packages to European standards.
Why recover condensate – and why monitor its quality?
Condensate is almost pure, hot water. According to Spirax Sarco, condensate retains about 18 % of the steam’s energy at 1 bar g and about 30 % at 14 bar g; returning it reduces make-up water heating, water purchase, treatment chemicals and blowdown (source).
However, condensate can be contaminated when heat exchangers leak (cooling water, product, sugar, milk, chemicals, oil) or by boiler water carryover. Even small amounts returned to the boiler can cause foaming, scaling and corrosion, wet steam, product contamination and lost production (Forbes Marshall).
How condensate contamination control works
- Continuous measurement: a conductivity sensor with temperature compensation in the condensate return line or bypass.
- Comparison: the controller displays conductivity and compares it with the set point.
- Automatic dumping: above the set point, a 3-way valve diverts condensate to drain (or an isolating valve closes and a dump valve opens) and an alarm is raised.
- Return: when conductivity is back within limits, condensate is returned to the feed tank automatically.
| Contaminant type | Typical sources | Detection |
|---|---|---|
| Raises conductivity | Cooling water, raw water, chemicals, salts, boiler-water carryover | Conductivity sensor (main method) |
| Does not raise conductivity | Oil, grease, sugar, organics | Add a turbidity / oil detector or dedicated analyser |
Oil, fats and sugar usually do not change conductivity – for sugar, dairy, food and edible-oil plants add a turbidity/oil sensor. ISE advises the right configuration for your actual contamination risks.
Condensate contamination control specifications
| Parameter | Value |
|---|---|
| Function | Conductivity monitoring, high-conductivity alarm, automatic diversion |
| Nominal pressure | PN40 |
| Max. operating pressure | 32 bar g |
| Max. operating temperature | 239 °C |
| Test functions | Alarm test, valve test, alarm reset |
| Temperature compensation | Automatic |
| Outputs | Diversion relay + alarm relay; 4–20 mA conductivity |
| Communication | Modbus RS485 |
| Diverter | 3-way valve or pair of 2-way valves (isolate + dump), electric or pneumatic |
Benefits of controlling condensate contamination
- Protects the boiler from foaming, scaling and corrosion.
- Maximises condensate recovery – less fuel, make-up water, chemicals and blowdown.
- Early detection of heat-exchanger leaks, reducing product loss.
- Accurate at any condensate temperature thanks to automatic compensation.
- 4–20 mA and Modbus to PLC/SCADA for monitoring and data logging.
Applications
- Food, beverage, dairy, sugar and brewing: condensate from heaters, pasteurisers and evaporators.
- Textile, paper, chemical and pharmaceutical process heat exchangers.
- Central condensate return systems in multi-department plants and industrial parks.
Reference standards
Feedwater and boiler water quality per EN 12953-10 (shell boilers) / EN 12952-12 (water-tube boilers); pressure equipment per PED 2014/68/EU; CE-marked electrical equipment (EMC 2014/30/EU, LVD 2014/35/EU).
FAQ
What conductivity set point should be used?
It depends on clean condensate quality and boiler feedwater requirements. Measure clean and contaminated condensate to choose the dump set point; ISE sets it during commissioning.
Does it detect oil or sugar?
Conductivity sensors do not detect oil, grease or sugar. Where these are the main risk, add a turbidity/oil detector.
Related solutions and products
- Automatic boiler TDS blowdown control
- Boiler TDS sensor
- Capacitive boiler level probe 4-20mA
- Boiler oxygen trim for fuel savings
Contact ISE
EQUIPMENT INDUSTRIAL SOLUTION CO., LTD (ISE) – Ho Chi Minh City, Vietnam – surveys condensate return systems and supplies and installs condensate contamination control systems.
Contact us: Sales +84 909 617 185 – Technical +84 979 117 185 – Email: [email protected]
