AMBITROL Coolants

Installations using 500 gallons or more of AMBITROL™ industrial coolant are eligible to receive Dow’s free annual coolant analytical service. Dow experts analyze your coolant every twelve months to ensure inhibitor potency and freeze protection are maintained at the desired level. If you are using a coolant other than an AMBITROL coolant, you may also qualify for our analysis service.

Coolant Analysis Program

AMBITROL coolants are monitored for the following fluid properties and chemistries:

Test
Concentration & Freeze Point
Chemical Properties
Corrosion Inhibitors
Corrosives & Scale Promoters
Contaminants & Other Glycols

Test	Test Significance (HTF)
Appearance
Color	Describes the color of the sample as it was received. Brand new AMBITROL inhibited glycol based heat transfer fluids are dyed blue-green, pink, blue, or yellow-green (depending on type) for leak detection. Fluids which are dark brown or black indicate substantial glycol degradation products, excessive contamination, and/or corrosion by-products.
Clarity	Properly installed and maintained fluid will be clear or only slightly hazy. Fluids with a hazy appearance either contain suspended solids or insoluble liquids (oils). Suspended solids may be due to fabrication debris or may form by precipitation with hard water ions (calcium or magnesium). The presence of oils may suggest leakage of oil cooled equipment has occurred, or that residual oils or greases were not removed prior to fluid installation. It may mean that excessive degradation of the glycol base fluid has occurred. The presence of haziness or sediment is not typically cause for fluid disposal since this problem can normally be remedied by on-line filtration. However, samples with gross levels of suspended material or insoluble liquids at more than 5% by volume means the material is no longer suitable as a heat transfer fluid for the system and is not tested due to the potential damage the fluid can cause analytical equipment.
Sediment	Fabrication debris is commonly found in fluids which were not cleaned prior to installation, e.g. welding flash, pipe scale, corrosion deposits, even dirt, sand and other contaminants can be present. Fluids re-circulating with high levels of sediment can cause erosion of piping and premature wearing of mechanical pump seals. The presence of sediment is not typically cause for fluid disposal since this problem can normally be remedied by on-line filtration. Note: Samples with gross levels of suspended material or insoluble liquids i.e. more than 5%, are no longer suitable as a heat transfer fluid for the system, and is not tested due to possible equipment damage.

Concentration & Freeze Point

Ethylene Glycol/ Propylene Glycol

Desired range is between 30%-60%. Gas chromatography is used to determine actual concentration of ethylene glycol and propylene glycol, as well as the presence of other contaminant glycols not used (i.e. diethylene glycol or triethylene glycol). In addition to providing the necessary freeze protection, the concentration of glycol is important for other reasons. With too low of a concentration, i.e. less than 25%, fluids are subject to bio-organism contamination and bio-film fouling. At too high of a glycol concentration, i.e. greater than 60%, no additional freeze depression is realized but heat transfer efficiency will fall off substantially.

Freeze Point

Dow recommends selecting a glycol concentration which freezes at least 5ºF below your lowest anticipated operating/exposure temperature. We calculate freeze point based on the measured amount of glycol.

Chemical Properties

Fluid pH

New Dow heat transfer fluids with a pH of more than 9.0. Fluid pH will typically decrease with time because of thermal-oxidative degradation of the glycol base fluid. Degradation of glycol produces acidic compounds which cause the pH of your fluid to decrease with time. The buffers present in our fluids minimize pH drop by neutralizing these acid compounds. Meanwhile the corrosion inhibitors will protect your system from corrosion as long as fluid pH remains above 8.0 and below about 10.5. Fluids with pH above 10.5 may require special attention and assistance from Dow Technical Service.

Fluids with pH between 7.0 and 8.0 can be re-adjusted back to acceptable ranges by suitable addition of 50% caustic. When such pH adjustment is necessary, we provide specific directions on how to do so. Should fluid pH ever fall below 7.0, we recommend fluid disposal because insoluble (oil-like) glycol degradation products will form at this low pH range, meaning it is no longer possible to restore the fluid to acceptable condition by simple pH adjustment i.e. does not remove the contaminants.

Reserve Alkalinity

Alkalinity of more than pH 5.5 found in 10 mLs of fluid sample. RA is a measure of the buffering capacity of the fluid.

Corrosion Inhibitors

Phosphate (PO₄)	AMBITROL coolants should have more than 2500 ppm of phosphates, to ensure adequate corrosion protection and buffering capacity. NORKOOL™ SLH contains phosphate based corrosion inhibitors which provide general metal corrosion protection and also act synergistically with borate based buffering additives to provide effective, long lasting control of fluid pH.
Tolyltriazole (3C7H7N)	AMBITROL coolants should be more than 100 ppm of tolyltriazole to ensure adequate corrosion protection of copper and copper alloys (yellow metals) like brass and bronze.

Corrosives & Scale Promoters

Dow does not analyze corrosion on a routine basis. It can be done on a special analysis when you group by pH.

Chloride	A corrosive ion. Properly installed AMBITROL coolants will have less than 25 ppm chloride. At high enough concentrations, the presence of chloride can render the inhibitor package ineffective. High chloride is caused by failure to use de-ionized or distilled water during system top-ups /dilutions. Its presence can increase the corrosion rate (most particularly pitting corrosion) of most metals. Systems containing more than 100 ppm chloride may experience excessive corrosion if other fluid parameters are also outside recommended ranges. The corrosive effect of chloride is more severe at higher fluid temperatures. Excessive corrosion rates caused by elevated chloride levels often can only be corrected by removal and replacement of the contaminated fluid.
Sulfate	A corrosive ion. Properly installed AMBITROL coolants will have less than 25 ppm sulfate. Sulfate is also caused by failure to use de-ionized or distilled water. In addition sulfates may also form by using sulfur-based (non-Dow) corrosion inhibitors such as MBT. Systems with more than 500 ppm sulfate may experience excessive corrosion, particularly if other fluid parameters are also outside recommended ranges. The corrosive effect of sulfate is more severe at higher fluid temperatures. Like chlorides, excessively high corrosion rates caused by elevated sulfate levels often can only be corrected by removal and replacement of the contaminated fluid.
Total Hardness	Expressed in ppm as calcium carbonate, with less than 200 ppm as CaCO₃ being desirable. It is the amount of calcium and magnesium ions present in your fluid. High hardness is caused by using a poor quality water such as river water, well water or even tap water. Hard water ions, like calcium and magnesium, will react with most corrosion inhibitors, but particularly phosphates, to form insoluble scales on heat transfer surfaces. This reduces the active concentration of corrosion inhibitors as well as decreasing heat transfer efficiency. Systems are susceptible to localized hot spots and excessive corrosion. To correct this problem, the fluid should be dumped, drained and re-filled. The system should be cleaned with industrial cleaner prior to re-filling with new fluids.
Ferrous metal corrosion rate	A calculated value based on the overall condition of your fluid. As a point of reference, new Dow fluids exhibit a ferrous metal corrosion rate of less than 0.05 mils per year, whereas the recommended maximum corrosion rate as established by ASTM is 0.5 mils per year. Dow Chemical has developed an extensive library for all of our fluids based on thousands of corrosion testing measurements. Dow reliably predicts the corrosion rate for our fluids to within plus or minus 0.1 mils per year (MPY). However it is not possible for us to accurately calculate corrosion rates for non-Dow fluids, mixtures which are predominately non-Dow in nature, or Dow fluids which have been altered significantly from their original design. The reported corrosion rate is an excellent tool in assessing the overall health of your system.
Copper alloys corrosion rate	A calculated value but data is specific to copper and copper alloys such as brasses and bronzes. Again, newly installed Dow fluids will exhibit a corrosion rate of less than 0.05 mils per year, while the recommended ASTM maximum is 0.5 mils per year.

Contaminants & Other Glycols

For properly installed and maintained AMBITROL the following limits to Total Degradation Acids should be adhered to:

Nitrite	AMBITROL heat transfer fluids do not contain sodium nitrite and its presence indicates non-AMBITROL fluid or perhaps a non-Dow fluid or additive. Should a nitrite based corrosion inhibitor be desired, Dow recommends the use of either NORKOOL SLH inhibited EG or NORKOOL LTC inhibited PG fluid.
Nitrate (NO₃)	Nitrate should not be present in any Dow fluid, not even NORKOOL SLH. Its presence typically signals the use of non-Dow products such as automotive coolants or the use of water treatment chemicals. While the presence of nitrates themselves are not normally detrimental, they are a good indicator of non-Dow fluid or atypical operation i.e. they should be zero or and no higher than 500 ppm.
Mercaptobenzothiazole (MBT)	Mercaptobenzothiazole (MBT) or mercaptobenzothiazole is a sulfur based, non-Dow additive. It is commonly used as a corrosion inhibitor by many water treatment companies owing to its low cost. MBT oxidizes readily to form disulfides and eventually corrosive sulfates, they are a good indicator of non-Dow fluid or atypical operation i.e. they should be zero or and no higher than 500 ppm.
Diethylene Glycol (DEG)	A contaminant glycol found in lower grade products such as automotive antifreeze, or those based on recycled ethylene glycols. In special circumstances, DEG may also form by excessive thermal degradation of mono-ethylene glycol. Thus, its presence always indicates an undesirable contaminant.
Triethylene Glycol	Typically used in gas dehydrators and may also be used in non-HVAC, industrial type heat transfer fluids such as Tritherm™. It is not present in new AMBITROL coolants so its presence indicates a contaminant product. Thus, its presence always indicates an undesirable contaminant.

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Thermal Fluids