Owners or former owners of property in the United States and Canada, where Entran II hose is or was installed, may qualify for settlement and may obtain information about a class action settlement for property damage claims involving the hose, including claim forms, at www.entraniisettlement.com, or by calling the Claims Administrator (1-800-254-9222).

Installation and Maintenance Notice to Heatway™ Entran II Systems Users

This information is intended for homeowners or users with Heatway™ Entran II Radiant Heating Systems in their homes.

Entran II hose, manufactured by Goodyear, is one of many component parts that were used in Heatway’s (CPS) Radiant Heating Systems from approximately 1989-1993. Goodyear neither designed nor manufactured the systems.

The vast majority of the more than 10,000 installations throughout the nation continue to perform satisfactorily. Where, however, the systems have not been properly designed, installed, operated or maintained, a small number of the systems have been experiencing problems, including damage to the Entran II hose. These design, installation, operation and maintenance problems should be corrected.

Goodyear has learned during the course of litigation that Heatway (CPS) never wrote an installation and maintenance manual for Entran II hose. Many homeowners have not previously received proper advice concerning the design, installation and maintenance of their systems. Still other homeowners have improperly been told to replace systems that are functioning properly and that with proper maintenance will continue to function for years to come.

The purpose of this document is to summarize accepted practices that, if followed, will help maximize the useful life of hydronic radiant heating systems.

The document is organized in two parts. The first provides a brief summary of some steps that a homeowner can quickly and easily take. The second part provides a more detailed explanation of accepted industry practices and guidelines for the design, installation, operation and maintenance of hydronic heating systems.

NOTICE
As a legal matter, Heatway (CPS) (and its distributors and installers) – not Goodyear – had and have the obligation to advise system users as to proper system design, installation, operation and maintenance. Goodyear has prepared this document, containing information it has developed with its experts during the course of litigation with Heatway (CPS), in an effort to assist in identifying the information that Heatway (CPS) should have ensured reached all system users, but which it has not. In doing so, Goodyear expressly reaffirms that it is neither waiving (nor changing) its position that dissemination of such information was the sole obligation and responsibility of Heatway (CPS) (and its distributors and installers).

Accepted Industry Practices for Owners of Hydronic Heating Systems

Accepted industry practices and guidelines for the installation, operation and maintenance of hydronic heating systems include the following:
1. All hydronic systems should be designed by a professional engineer registered in the state of the installation. A summary of accepted industry practices and guidelines is attached. If you do not know if a professional engineer designed your system, you should have either a professional engineer or a master plumber check your system to see if the attached practices and guidelines have been followed. If they have not been followed, your system should be corrected. If you have had to replace metal components in your system, such as boilers, expansion tanks, valves, etc, this is likely a sign of excessive corrosion and improper installation and maintenance.

2. You should have the system fluid checked on an annual basis to assure that the fluid has the proper pH (a measure of acidity) and the proper level of corrosion inhibiting chemicals (and the proper level of glycol if your system uses a water-glycol mix). A plumbing company or a water treatment company can perform these tests for you. Please provide them with the attached information.

3. If you wish, you can perform a preliminary check of your system fluid by draining a few ounces of fluid into a clear plastic or glass container. If the fluid contains visible sediment, particulate matter, or is dark in color, you should promptly have a plumbing company or a water treatment company test the fluid and replace or treat it as per the attached information.

4. You can also perform a preliminary check of the pH of a sample of the fluid. A standard pH test kit, or test strips can be obtained at any store that carries swimming pool supplies. It is important that you maintain the system fluid pH between 8.5 – 10.5. If the pH of your system fluid is different, you should promptly have a plumbing company or a water treatment company test the fluid and replace or treat it as per the attached information.

5. Your system should have a strainer to screen and trap sediment and particulates. This strainer should be inspected, at a minimum, at the beginning and end of the heating season. Any sediment and particulates in the strainer should be removed. If you have a bypass filter (as recommended by Dow), the filter should be checked and/or replaced at the intervals recommended by the manufacturer of the bypass filter.

6. Following the attached guidelines will help maximize the useful life of your hydronic heating system. These include making sure that your system is not operated in excess of 180º F. The system fluid temperature should typically be maintained in the range of 100º to 130º F. If your system is operating in excess of this temperature range, you should have either a professional engineer or a master plumber check your system to make sure that the practices and guidelines on the following pages have been implemented. If they have not been followed, the system should be corrected.

Industry Practices and Guidelines for the Design, Installation and Operation of Hydronic Heating Systems
Maximizing the useful life of hydronic radiant heating systems, including all components thereof, requires adherence to one fundamental requirement. The systems must be designed, installed, operated and maintained in accordance with accepted industry standards and guidelines, as well as various publications by the manufacturer of the systems -- Heatway (CPS). Adherence to these guidelines, including proper system fluid treatment, will minimize the potential for corrosion in the system. Corrosion, if left unchecked, can cause premature failure of all components of a hydronic radiant heating system, including the Entran II hose.

These recommendations have largely been drawn from industry standards, guidelines, and recommendations of the system manufacturer, Heatway (CPS), including the following:
1. ASHRAE (American Society of Heating, Refrigeration, and Air Conditioning Engineers) Handbook, 1987, HVAC Systems and Applications;
2. ASHRAE Handbook, 1985, Fundamentals;
3. Hydronics Institute, Snow Melting Calculation & Installation Guide, Manual
S-40 (1993) including Technical Topic TT#2A, Anti-freeze in Hydronic Systems;
4. Hydronics Institute, Advanced Installation Guide for Hydronic Heating Systems, Manual 250 (1991);
5. Radiant Panel Association Standard Guidelines (1997);
6. Bell and Gossett Reprint, Hydronic Systems: Analysis and Evaluation (1968,1969);
7. Bell and Gossett, Hydronic Systems Anti-freeze Design, Bulletin No. TEH-176 (1965);
8. Bell and Gossett, Air Control for Hydronic Systems, Bulletin No. TEH-575 (1966);
9. Uniform Mechanical Code (UMC) (1988);
10. Heatway Radiant Floors and Snowmelting, Twintran Application Manual (1989);
11. Heatway’s “Minimizing Corrosion in Hydronic Systems,” by Mike Chiles;
12. Heatway’s “Water Treatment in Hydronic Systems,” by Mike Chiles;
13. Heatway’s “Wet Heat Water Treatment,” A Guide to Hydronic System Cleaners & Corrosion Proofer;
14. Heatway’s letter of November 14, 1996 to “All Heatway Representatives, Distributing Wholesalers, and Contractors” re: “Water Quality Analysis Request Program;”
15. Dow’s “Engineering and Operating Guide for DOWFROST and DOWFROST HD Inhibited Propylene Glycol-based Heat Transfer Fluid;”
16. Union Carbide’s “Ucartherm Heat Transfer Fluids: Optimum Protection for Heating, Ventilating, and Air Conditioning Systems;”
17. Union Carbide’s Technical Bulletin: “Dilution of Ucartherm Heat Transfer Fluid,” form UC-38.

SYSTEM DESIGN AND INSTALLATION
Heatway, in its Twintran Application Manual, stresses the need to “Obey the Building Codes” and states that “The steps we describe in this manual must not take the place of local, regional, or national building codes and regulations. You must take the responsibility to ensure that your work in [sic] in compliance with relevant codes.” It further advises to “Use Designs from Licensed Professionals.”¹. Unfortunately, Heatway (CPS) did not provide this warning in any Entran II Application Manual, because it never wrote one. Most of the hydronic radiant heating systems observed to date in which there is some claim of deterioration of the system and/or the Entran II hose, were not designed by licensed professionals. Each contains one or more deviations from the following accepted industry standards and guidelines. These design and installation deficiencies contribute significantly to corrosion in the system and poor system performance.
1. All of these hydronic systems should be designed by a professional engineer registered in the state of the installation. Heatway’s own Twintran manuals². also state this.
Reason: Hydronic radiant heating systems are not simple. They are complex and should be designed by a professional engineer experienced with the correct design of hydronic systems. The wide variation in installed configurations, with numerous instances of incorrectly installed components, further supports this concern. It is also likely that the state regulatory licensing agency requires these systems to be designed by a registered professional engineer.
2. The owner or the owner’s representative must perform proper maintenance of the system fluid, see discussion at page 6. This is the main recurring system deficiency.
Reason: ASHRAE,³ HI,⁴. B&G⁵. and glycol manufacturers (such as Dow⁶. and Union Carbide⁷. ) recommend that the operating fluid be checked annually for pH, inhibitor level, and concentration of glycol. Heatway (CPS) has also endorsed and made these same recommendations⁸. The fluids must be checked regularly in order to maintain proper system operation. In the vast majority of the installations investigated to date, neither Heatway (CPS) nor the suppliers or the installers of these systems, has educated or instructed the owners about proper care for the operating fluid in these systems. As the pH drops and inhibitors are exhausted, the system fluid becomes extremely corrosive, resulting in accelerated failures of system components. For example, there have been instances where cast iron boilers have reportedly failed after 5 to 7 years of operation. ASHRAE cites expected life of cast iron boilers in properly maintained systems to be 30 to 35 years. As this example shows, extreme corrosion is taking place in these systems, due to the temperature of the fluid, the low pH, loss of inhibitors, and incorrectly installed system components.
3. The circulating pump(s) in the system should be downstream of the boiler, on the boiler supply (hot water outlet) pipe.⁹
Reason: Proper location of the circulating pump, together with proper location of the expansion tank minimizes introduction of air into the system from any loose connections. Improper location can contribute to corrosion of the system and can reduce the percentage of glycol in a glycol-based system.
4. The expansion tank in the system should always be located on the inlet to the pump, not on the pump discharge.¹⁰
Reason: With the expansion tank on the pump discharge, portions of the piping system operate at less than atmospheric pressure, since the pump head (pressure differential produced by the pump) subtracts from the pre-charge pressure in the expansion tank. The expansion tank is the point in the system where no pressure change occurs whether the pump is operating or not. Since the pumps on these systems have relatively higher heads than normal circulating pumps, (due the fact that the hydronic hose has a higher pressure drop per given length than copper pipe) the pressures on the inlet side of the pump and piping, in systems where the expansion tank is located on the pump discharge, can be negative with respect to atmospheric pressure. This increases air entering the system at any locations where the system pressure is less than atmospheric pressure.
5. The air separator should be located at the inlet to the pump, at the boiler outlet (hot water supply to the system). A “Spirovent” type of air separator should be used on all these systems as it has substantially better separation efficiency than the “air scoop” type of separators that are installed on most of the systems.
Reason: Air separators operate most effectively at the point in the system where air is easiest to remove. This is at the point where the pressure is the lowest (pump inlet) and the temperature is the highest (boiler outlet). The “air scoop” type of vent is nothing more than an enlarged portion of the piping system where air is gathered and collected, to be vented from the system. The “Spirovent” type of air separator uses mechanical action of the fluid within the air separator to assist in air removal.
6. Air separators must have automatic air vents installed on them to allow air to automatically vent from the air separator when it is collected. The vent cap on the air vent must be loose in order to allow air to escape when the vent discharges.
Reason: If the air vent is not installed or not operating properly, air that is collecting in the system cannot get out. Air that accumulates in the system can cause air blockages and, if the system fluid is not properly treated with corrosion proofers, the air will react with the copper and iron components in the system, causing corrosion and deterioration of all components of the system.
7. Systems should have high point vents and low point drains.
Reason: When the systems are filled and drained, which is necessary on properly maintained systems, high point vents and low point drains are needed to assure that all the air is vented from the system when it is filled. They also allow the system to be drained completely by allowing air to enter the system when drained from a low point. In addition, when the system is filled or refilled, air vents allow air to be vented from the system during filling so air binding of the system does not happen. Air binding prevents fluid from flowing through the hydronic hose.
8. Dielectric unions should be installed on any copper to iron (or steel) connections in the system, to prevent electrolytic corrosion of the iron and copper system components
Reason: Copper and iron (or steel) produce an electric potential between them when physically connected. If not dielectrically separated, the electric potential causes the iron or steel components in the system to act as a sacrificial anode, releasing corrosion products into the system.
9. Strainers should be installed on all systems. Additionally, Dow recommends the use of bypass filters for removal of foreign solids.¹¹
Reason: A strainer acts as an in-line filter (or screen) to remove foreign products (such as corrosion products) from a system at a controlled location should periodically open and drain the strainer. If corrosion products are not removed from the system at a controlled location, such as a strainer, they can then circulate throughout the system. At points in the system where the fluid velocities are lower, the corrosion products can settle out of the liquid and plug circuits in the system. A bypass filtration system, e.g., polypropylene cartridges with a nominal rating of 20-50 microns, will remove smaller particulates than would be removed by a standard wye strainer.
10. The system fluid temperature should typically be maintained in the range of 100º to 130º F, with a fluid temperature drop of no more than 20º F. In systems where the boiler supplies fluid to both in-floor radiant heating and to fin-tube baseboard heating, the piping system must have a properly operating 3-way or mixing valve present.
Reason: Maintaining fluid temperatures in the above range maximizes the useful life of a hydronic system. In general, the rate of system corrosion and the rate of deterioration of system components will increase as the operating temperature of the system fluid increases. Heatway’s Twintran Application Manual notes as follows: “A floor heating system, due to its nature, requires a longer period of time to respond to changes in its thermostat setting. However, once the thermal mass of the floor is heated, it is usually easy to maintain the desired level of comfort. Therefore, the most appropriate use of a radiant floor heating system is where the heated structure is kept at a relatively constant temperature.”¹² Heatway further notes: “Water Temperature Required.” As little as 90º F in well insulated slab floor homes in moderate weather. Most slabs require a range of 100º to 130º and rarely more than 150º.”¹³ Heatway also notes: “For residential or light commercial applications you should keep the surface temperature of the floor no higher than 85º F.”¹⁴ Some homes, however, use the same boiler to supply system fluid to both a radiant floor heating system (which should typically operate at 100º to 130º) and to fin-tube radiators, which are often set to operate at 180º to 200º F (i.e., in excess of the maximum 180º F temperature allowed by Heatway’s warranty). These systems should contain mix valves that mix and reduce the fluid temperature to the in-floor radiant hose such that its temperature is maintained at the recommended 100º to 130º and should use copper to transport the higher temperature fluid to the fin-tube radiator. In instances in which Entran II hose has been used to connect to a fin-tube radiator, it is not being used as a radiant, or energy transfer, hose.
11. Hose connections to manifolds should be checked for leakage. If leakage is present, the connections should be repaired by splicing in a new section of hose and connecting it to the manifold using a constant tension style clamp.
Reason: In 1992 Heatway (CPS) determined that their method of connecting the hose to manifolds, using screw clamps, was sensitive to variations in how firmly the installer tightened the screw clamp. Heatway (CPS) subsequently published “Installation Guidelines for Field Repairs For Entran Energy Transfer Hose” that call for use of BarbTite adhesive with Heatway Self Tite clamps (a type of constant tension clamp).¹⁵ Heatway currently offers Entran Onix Field Repair Kits through its published price guide.
SYSTEM FLUID TREATMENT
As indicated above, ASHRAE,¹⁶ HI,¹⁷ B&G¹⁸ and glycol manufacturers (such as Dow¹⁹ and Union Carbide²⁰) all recommend that the operating fluid be checked annually for pH, inhibitor level, and concentration of glycol (if used). Heatway (CPS) has also endorsed and made similar recommendations. ²¹ Failure to properly treat and maintain a hydronic system can result in rapid, severe damage to system components. Untreated or improperly treated systems will have elevated levels of copper and iron in the recirculating fluid, due to corrosion of metal components. This is preventable by using standard industry practices, as described below.
Non Glycol Systems
(Also applicable to Glycol Systems)
1. Before any system is filled, it should be properly cleaned and flushed using a mixture of 1 to 2 percent trisodium phosphate. Alternatively, a neutral pH surfactant (detergent) type cleaner can be used to remove oils and greases.
Reason: As stated by Dow, “New systems are typically coated with oil, grease or a protective film during fabrication, storage, or construction. Dirt, solder flux, and welding and pipe scale can also cause problems. Therefore, thorough cleaning of new systems is recommended. A solution of 1 to 2 percent trisodium phosphate can be used with water for flushing the system.”²²
2. If an inhibited glycol (one that includes corrosion inhibitors) is not used in the system, the system should be filled with good quality potable water, with an inhibitor package added to maintain proper pH and to minimize any corrosion.
Reason: It is standard industry practice to maintain low metal ion levels through the use of effective chemical treatment programs and by employing appropriate mechanical precautions, such as filtration. A well treated system will typically have levels of metal ions that are less than 0.1 ppm (mg/L) of Copper, and less than 0.2 ppm (mg/L) of Iron.
3. The system should include a by-pass feeder.
Reason: Use of a by-pass feeder will facilitate adding chemical treatments to the system fluid, as and when it become necessary, without the need to disassemble piping or other equipment. In most cases, if there is a filter present (as is recommended above), it can also serve as a by-pass feeder. The by-pass feeder/filter can also serve as a convenient point from which fluid samples can be taken for testing purposes.
4. Check the system fluid on an annual basis to assure that the fluid has the proper pH and the proper level of corrosion inhibiting chemicals.
Reason: Testing the pH of the system fluid is a quick, easy, and inexpensive indicator of the health of a hydronic system. Testing for and maintaining the proper level of corrosion inhibiting chemicals will assure that corrosion in minimized. In each case the test is simple to carry out and could easily be done by either the homeowner or a plumber. A pH test may be done using a low cost pH meter (approx. $70) or using a wet test method that is similar to the type used in maintaining swimming pool waters. The inhibitor tests are equally simple – taking the form of drop tests (like those used on swimming pools) or simple “dip strips,” where you put a strip of paper (similar to pH paper) into the fluid and then compare the color that develops with a standard. A decrease in the fluid pH indicates a system maintenance problem.
5. Maintain the system fluid pH between 8.5 – 10.5.
Reason: Maintenance of a pH in this range, using a buffering system based on borate, morpholine or phosphate, will minimize corrosion of copper and mild steel components. As a general rule, as the pH goes down (becomes more acidic), the amount of soluble metal ions increases. The lower pH also has the effect of accelerating the corrosion process. It is standard industry practice to maintain low metal ion levels through the use of effective chemical treatment programs and by employing appropriate mechanical precautions, such as filtration. A well treated system will typically have levels of metal ions that are less than 0.1 ppm (mg/L) of Copper, and less than 0.2 ppm (mg/L) of Iron.
6. Examples of products that are commercially available and the type of corrosion inhibitors used in them are:
Nalco 2536 (Borate/Nitrite/Azole)
Nalco 2820 (Molybdate/Borate/Azole)
Drew DWS 2802 (Nitrite/Borate/Azole)
Drew DWS 2808 (Nitrite/Borate/Azole)
Drew DWS 2818 (Molybdate/Borate/Silicate/Azole)
In addition to these, similar products can be obtained from BetzDearborn, Calgon, Chemtreet and a large number of other regional companies. Heatway also offers a corrosion proofer, CP-3. One can find listings for specific local water treatment companies in the Yellow Pages or equivalent type of phone directories.
Glycol Systems
7. Items 1-6 listed above (Non Glycol Systems) are equally applicable for glycol systems. Indeed, since glycol breaks down to form organic acids, regular testing to assure proper pH and the proper level of corrosion inhibiting chemicals is essential.
8. The glycol used in the system should be diluted with water that meets the recommendations of the manufacturer of the glycol. Typically this requires use of either distilled or deionized water.
Reason: As noted by Dow, “Water used to dilute DOWFROST fluids must meet certain minimum standards for purity. Impurities in dilution water can increase metal corrosion, aggravate pitting of cast iron and steel, reduce the effectiveness of corrosion inhibitors, increase inhibitor depletion rate, cause formation of scale and other deposits on heat transfer surfaces, and cause clogging of system components . . . Distilled or deionized water is recommended.”²³
Union Carbide, a large glycol manufacturer, makes similar recommendations in their technical bulletin “Dilution of Ucartherm Heat Transfer Fluid.”²⁴
9. While one can obtain uninhibited glycol and add the inhibitor separately, the best approach is to buy glycol from the major suppliers and use it for the initial fill of the system. Examples of available inhibited glycols included:
Dowfrost or Dowfrost HD(propylene glycol)- Dow
Dowtherm SR-1 (ethylene glycol) - Dow
Ucartherm HTF (ethylene glycol) - Union Carbide
Ucar Foodfreeze (propylene glycol) - Union Carbide
10. If the annual testing of the pH level and the level of inhibitor indicates that either is in need of adjustment, the fluid should either be drained and the system refilled, or the fluid should be chemically treated to bring the pH level and the level of the inhibitor back to acceptable levels. Heatway offers an antifreeze additive, Alphi 11. Also, the inhibitors listed in the “non-glycol” section can be used to treat glycol containing systems. Additionally, manufacturers of glycols, such as Union Carbide market their own proprietary products to re-inhibit glycol systems. For example, Union Carbide markets the following products:
Ucartherm Inhibitor 1000 - a ferrous metal inhibitor booster
Ucartherm Inhibitor 2000 - a ferrous metal inhibitor and pH booster
Ucartherm Inhibitor 3000 - a yellow metal inhibitor and pH booster
11. In addition to annually checking the pH level and the level of corrosion inhibiting chemicals in the system fluid, glycol systems should be checked annually to assure that the percentage of glycol exceeds 20%.
Reason: If the level of glycol is allowed to drop below 20%, there is a greater potential for biological contamination. Again, the particular manufacturer’s recommendations should be followed. Dow, for example, states “To ensure maximum effectiveness for corrosion protection, the inhibitor package is designed for a minimum 25-30 volume percent concentration of glycol in water.”²⁵
Percent glycol can be determined by the homeowner, or a plumber, using a refractometer (cost approx. $100) or a glycol tester such as used for a car’s antifreeze (cost approx. $40). Also a plumber/mechanical contractor could arrange for testing to be done by a water treatment company, if they did not wish to do it themselves.^{25 Id.}

1 Heatway Radiant Floors and Snowmelting, Twintran Application Manual (1989).
2 Id.
3 See, e.g., ASHRAE (American Society of Heating, Refrigeration, and Air Conditioning Engineers) Handbook, 1987, HVAC Systems and Applications; and ASHRAE Handbook, 1985, Fundamentals.
4 Hydronics Institute, Advanced Installation Guide for Hydronic Heating Systems, Manual 250 (1991).
5 Bell and Gossett, Hydronic Systems Anti-freeze Design, Bulletin No. TEH-176 (1965).
6 Dow’s “Engineering and Operating Guide for DOWFROST and DOWFROST HD Inhibited Propylene Glycol-based Heat Transfer Fluid.”
7 Union Carbide’s “Ucartherm Heat Transfer Fluids: Optimum Protection for Heating, Ventilating, and Air Conditioning Systems.”
8 See, e.g., Heatway Radiant Floors and Snowmelting, Twintran Application Manual (1989) (“Every two years, you should have your fluid tested for any change or else flush the system and re-charge it with a new solution. Use a 2% by weight tri-sodium phosphate in your solution to help maintain proper pH”); Heatway’s “Minimizing Corrosion in Hydronic Systems,” by Mike Chiles, (“Treat the water with a good quality corrosion proofer”).
9 Heatway has also made this recommendation. See, e.g., Heatway’s “Minimizing Corrosion in Hydronic Systems,” by Mike Chiles, (“Locate Circulators in the Correct Position. Pump into radiant circuits”).
10 Id. (“The primary, or boiler, circulator should not be “pushing” into the “expansion tank”). 11 Dow’s “Engineering and Operating Guide for DOWFROST and DOWFROST HD Inhibited Propylene Glycol-based Heat Transfer Fluid,” at p. 11 .
12 Heatway Radiant Floors and Snowmelting, Twintran Application Manual (1989).
13 Heatway Radiant Floors and Snowmelting, Twintran Application Manual (1989).
14 Heatway Radiant Floors and Snowmelting, Twintran Application Manual (1989).
15 Heatway’s “Installation Guidelines for Field Repairs For Entran Energy Transfer Hose.”
16 See, e.g., ASHRAE (American Society of Heating, Refrigeration, and Air Conditioning Engineers) Handbook, 1987, HVAC Systems and Applications; and ASHRAE Handbook, 1985,Fundamentals.
17 Hydronics Institute, Advanced Installation Guide for Hydronic Heating Systems, Manual 250 (1991).
18 Bell and Gossett, Hydronic Systems Anti-freeze Design, Bulletin No. TEH-176 (1965).
19 Dow’s “Engineering and Operating Guide for DOWFROST and DOWFROST HD Inhibited Propylene Glycol-based Heat Transfer Fluid.”
20 Union Carbide’s “Ucartherm Heat Transfer Fluids: Optimum Protection for Heating, Ventilating, and Air-Conditioning Systems.”
21 See, e.g., Heatway Radiant Floors and Snowmelting, Twintran Application Manual (1989) (“Every two years, you should have your fluid tested for any change or else flush the system and re-charge it with a new solution. Use a 2% by weight tri-sodium phosphate in your solution to help maintain proper ph”); Heatways’s “Minimizing Corrosion in Hydronic Systems,” by Mike Chiles, (“Treat the water with a good quality corrosion proofer”).
22 Dow’s “Engineering and Operating Guide for for DOWFROST and DOWFROST HD Inhibited Propylene Glycol-based Heat Transfer Fluid.,” at p. 97. 23 Dow’s “Engineering and Operating Guide for DOWFROST and DOWFROST HD Inhibited Propylene Glycol-based Heat Transfer Fluid,” at p. 9.
24 Union Carbide’s Technical Bulletin: “Dilution of Ucartherm Heat Transfer Fluid,” form UC-38.