Oxygen entry
Make-up water, a leak or air entry brings oxygen into the closed loop.
By problem
Corrosion and Sludge in Closed-Loop Systems
Water in a closed heating or cooling loop is replaced rarely. If oxygen, pH and bacteria are not controlled, the metal corrodes. Iron oxide sludge, also called magnetite in plant use, blocks narrow passages.
Why does it happen?
Mixed metals
Steel, copper and aluminum corrode at different rates in the same water.
Low flow
Iron oxide sludge and bacteria hold in a dead leg.
First dirt
Oil, swarf and installation dirt stay on the surface before start-up.
What damage does it cause?
Signs
- The water turns red-brown, or iron oxide comes from the filter.
- A radiator or a fan coil does not heat or cool in one area.
- Pump noise rises and the flow falls.
- pH, conductivity or iron analysis is outside the target.
- The water smells, or a slimy deposit is visible.
How do you solve it?
Chemical flush
Before start-up or during maintenance, a flush removes collected dirt and deposits.
Corrosion inhibitor
A closed-loop inhibitor protects steel and the selected copper or aluminum surface.
Biological control
Microbiological contamination in closed cooling and in air-conditioning water is controlled separately.
Freeze protection
At low temperature, freezing and corrosion are handled together. The dosage is selected from the system analysis.
Our recommended products
This page does not give a dosage or a percent. Select the product from the metal type and the system analysis.
Ck 13
Nitrite-Based Corrosion Inhibitor for Closed-Loop Heating and Cooling Systems – Copper Protection
It protects copper surfaces against corrosion in closed-loop heating and cooling systems.
Ck 133
Nitrite-Based Corrosion Inhibitor for Closed-Loop Heating and Cooling Systems – Copper and Aluminum Protection
It protects copper and aluminum surfaces against corrosion in closed-loop heating and cooling systems.
Ck 42
Molybdate-Based Corrosion Inhibitor for Closed-Loop Heating and Cooling Systems – Copper Protection
It is a molybdate-based corrosion inhibitor for copper surfaces in closed-loop heating and cooling systems.
Ck 422
Molybdate-Based Corrosion Inhibitor for Closed-Loop Heating and Cooling Systems – Copper and Aluminum Protection
It is a molybdate-based corrosion inhibitor for closed-loop heating and cooling systems.
C-amin 42
Corrosion Inhibitor for Closed-Loop Heating and Cooling Systems
It is an amine-based corrosion inhibitor for closed-loop heating and cooling systems.
C biocide 900
Biocide for Closed Cooling Systems
It is a biocide for closed cooling systems. It prevents microbiological contamination.
C biomid
Biocide for Air Conditioning Systems
It is a biocide for air conditioning and climate control systems. It prevents microbiological contamination.
Defrogen M
Antifreeze and Corrosion Inhibitor
It protects closed-loop heating and cooling systems against freezing and corrosion.
Cewa 200
Cleaning Product for Closed-Loop Heating and Cooling Systems
It is a product for the flushing and general cleaning of closed-loop heating and cooling systems. It helps to remove dirt and deposits.
Frequently asked questions
Does a closed-loop corrosion inhibitor also work in a heating circuit?
Yes. Ck 13, Ck 133, Ck 42, Ck 422 and C-amin 42 are for closed-loop heating and cooling systems. A heating circuit is in this group. Use Ck 13 or the molybdate-based Ck 42 for copper. Use Ck 133 or Ck 422 for copper and aluminum. C-amin 42 is amine-based.
When do you do a chemical flush?
Remove collected dirt and deposits before start-up, or when the water turns brown and the flow falls. Cewa 200 removes this dirt by flushing in closed-loop heating and cooling. After the flush, put the corrosion inhibitor in service.
When do you need a biocide?
You need a biocide when the water smells, when a slimy deposit is visible, or when closed cooling has microbiological contamination. C biocide 900 is for closed cooling. C biomid is for air-conditioning water.
Is Defrogen M only an antifreeze?
No. Defrogen M protects closed-loop heating and cooling against both freezing and corrosion. The dosage is set from the system analysis.
We help you select the inhibitor for your heating and cooling circuit
Send the system volume, the metal types and your latest water analysis. Our technical team will reply on the inhibitor, the flush and biological control.
We reply to quote requests within 12 hours.