Closed Heating and Chilled Water systems require an inhibition treatment program to prevent corrosion, deterioration of components and loss of heat transfer efficiency.  

Why Do Closed Systems Have Corrosion?

The introduction of dissolved oxygen from the raw water makeup is the primary cause of corrosion.  Mild steel and iron corrode rapidly under these conditions, releasing small flakes of rust into the recirculating stream.  These particles are abrasive and tend to erode the components of the system.  This can be particularly harmful in the area of pump seals.

The results of corrosion and scaling in recirculating systems are;

  • Damage to pump seals
  • Plugged lines or zones
  • Loss of heat transfer efficiency
  • Interruption of services
  • High maintenance costs
  • Replacement of capital equipment

Chemical Treatment Products for Closed Systems

PACE Chemicals Ltd.  has developed several effective corrosion inhibitors in our BAR COR CWS product line to provide a monomolecular film of protection.  Our programs also provide a pH buffer and protection against the corrosion of soft metals such as copper, brass, bronze, etc.  By coating all internal surfaces of piping and equipment with a protective film, we ensure no corrosive attack is possible.  Our film forming inhibitors provide excellent corrosion rate protection as recommended by the Association of Water Technologies (AWT).  

  • Mild steel corrosion rates <0.50 mpy
  • Copper corrosion rates <0.10 mpy

PACE Chemicals Ltd. also provides corrosion inhibitors for systems with aluminum heat exchanger metallurgy, as these systems have restrictive pH requirements.

Consult with your PACE Chemicals Ltd. representative to determine which closed loop inhibitor treatment is best suited for your application, or email us at to schedule a survey of your closed loop system.

Refer to our Closed Loop technical bulletins below for more information.