Azole Testing

TECHNICAL BULLETIN

Azole Testing: Importance in Chiller Plant Operation

Azole testing is in the best interest of anyone who operates a chiller plant.

WHY AZOLE TESTING IS IMPORTANT

Most copper-bearing alloys are located at the heart of a chiller plant, in the chiller itself. Corrosion coupon results are only a relative indication of “water chemistry health,” because they do not take into account the condenser tube bundle skin temperatures.

Premature chiller replacement is a very costly proposition, and azole testing can ensure that this equipment is properly protected.

COPPER PROTECTION AND AZOLE FUNCTION

Most cooling water treatment programs for copper-bearing systems include azole as part of the formulation. When fed correctly, azoles supply enough active protection to the recirculating water to protect copper metallurgy throughout the system.

Copper is relatively corrosion resistant, and a small amount of azole provides significant protection when properly maintained.

WHEN TO TEST FOR AZOLE

Azole should be tested in open recirculating cooling systems, including chillers.

Never assume that a particular product contains the proper amount of azole. Many suppliers use “one size fits all” formulations that may not match system-specific demand.

DO’S AND DON’TS OF COPPER CORROSION CONTROL

Don’t:

  • Don’t assume that enough azole is in a particular formulation to meet every condition
  • Don’t rely on copper corrosion coupons as the sole indication of good results

Do:

  • Do run copper testing and identify azole demand
  • Do ensure azole levels in recirculating water exceed demand by 0.5–1.5 mg/L
  • Do feed supplemental azole or azole-containing inhibitor as needed
  • Do use ORP to control oxidant programs; excess oxidant can destroy protective azole films
  • Do use special precautions when laying up copper tube bundles

SUPPORT

Your Kroff Chemical Company representative can review and recommend the proper program for your specific application.

DISCLAIMER

The information contained in this bulletin is, to the best of our knowledge, true and accurate, but all recommendations or suggestions are made without guarantee, since conditions of use are beyond our control. Kroff Chemical Company, Inc. disclaims any liability incurred in connection with the use of this data or suggestions.