Increase Profits and Reduce Warranty Returns with Proper Antifreeze Mix

As I look back on my past, I'm grateful for the many opportunities I've had with the geology, water chemistry, water well and geothermal heat pump industries. One of my earliest assignments in these ventures was to study the effects of water chemistry as it related to scaling incrustation and corrosion of piping systems. Early on, I learned the importance of the galvanic series (Figure 1). The galvanic series is a guideline to indicate the susceptibility of dissimilar metals to form a battery cell which will corrode a less noble metal and deposit it on a metal which is higher on the galvanic scale. Lessons learned from investigating failures of a multiple number of piping situations taught me to avoid the use of ferrous metals in “open systems.” If working with an open system containing natural water or well water, the materials of choice were always polyethylene, PVC, copper, brass or stainless steel. To use galvanized or black iron fittings, which are very low on the galvanic series, was simply asking for a failure within a few years. The majority of geothermal heat pump manufacturers have imparted this same knowledge into their piping materials suggestions. Yet to my knowledge, no manufacturer has taken time to educate anyone about the consequences that may result if lower-cost, dissimilar metal fittings are used. Nor have they mentioned that when ferrous metals are used, as is the case for cast iron body loop pumps, proper loop fluid chemistry is critical for longevity of the system.

We can apply this to the selection and mixing of antifreeze. Low-cost antifreeze solutions typically lack the needed corrosion inhibitors to prevent galvanic corrosion. Premium-grade antifreeze solutions are often double the cost of uninhibited antifreeze. The extra cost buys broad-spectrum corrosion inhibitors that protect a wide range of metals within the system. Inhibitors alone will not provide total protection. Ultimately, the behavior of an antifreeze solution and its ability to protect or corrode a system depend upon the type of antifreeze, its corrosion inhibitors and the quality/purity of the makeup solution. Low-purity makeup solutions will quickly deplete even the best inhibitors and render otherwise safe antifreeze corrosive.

Distributors working with geothermal equipment have a great deal to gain if they provide a complete package for the system, which includes pipes, fittings, water treatment solution when needed for southern climates and antifreeze for those northern climate installations requiring freeze protection. The value added for this service can cost between $300 to $800 per system. If the distributor doesn't provide this function and leaves it to the dealer, contractors might take numerous shortcuts, resulting in equipment failure, dissatisfied customers and repeat warranty claims, none of which help to increase profits. Instead, both you and the dealer suffer substantial lost time, lost profit and declining consumer confidence.

Installing contractors need to know why certain water-treatment solutions are used and the importance of maintaining a proper solution concentration. They need to understand the consequences and liabilities they are exposing themselves to when not using the recommended system fill, and what actions may be needed to recover a system if the solution becomes corrosive. To these effects, it is very likely that your local water-treatment manufacturer's representative would jump at the opportunity to sponsor a class for you and your dealers. The educational benefits of such a class will provide a win-win-win for you as the distributor, your rep and the dealers who attend.

Figure 2 lists a variety of system solutions I've encountered and their suitability for use with geothermal loops.

Case Histories

I prefer teaching from examples rather than cut-and-dry tables of rules and regulations. You can learn a great deal from the experiences of others and how they resolved their problems. The following is a series of four case histories of systems “gone sour” due to a lack of knowledge on the part of the installing contractor. Hopefully, you will identify with one or more of these cases and discover a solution to avoid similar misfortune in the future for yourselves and your dealers.