Mechanical rooms all over NYC have water-using HVAC loops filled with glycol. Many people think glycol loops are “set-it-and-forget-it”. However, proper care for glycol loops is imperative to prevent disastrous situations.
Understand the Volume of your Glycol Loop
The first step in glycol loop maintenance is to truly understand the volume of the loop. No method to determine the volume of a loop is perfect. The best method to estimate the volume of a loop is to drain the entire loop through a water meter and record the volume. This method works well but is sometimes impractical based on the size and use of the loop. In addition, any below grade piping and horizontal piping may not drain fully. A second viable option to determine volume is a chemical test. During this test, a tracer chemical is added to the loop and allowed to circulate. Post circulation, a sample can be analyzed in a lab and the chemical concentration can be used to determine a solid estimate of the total volume in the loop. Both options listed above will give accurate estimates of the volume, but it’s important to remember that they are just estimates.
Periodic Sampling of your Glycol Loop
After the volume of a glycol loop is well established, periodic sampling is required to verify the freeze protection provided by the glycol in the system. Leaks can develop and as maintenance is done on the loop liquid will be lost. Each time liquid is lost, the freeze protection drops. Periodic sampling is the only way to have confidence that your system is still well protected. Quarterly sampling is recommended, and the sample will provide information on the type and percentage of glycol in the loop, the corresponding freeze protection and will give evidence if the glycol has degraded to an unhealthy status. Reviewing the sampling results is important and will alert you if additional glycol is needed or not.
Adding Glycol Properly to Maintain Freeze Protection
Should additional glycol be required a calculation will be needed to determine the correct quantity to be added. Typically, 100% glycol will be added in a volume that will bring the overall loop to a minimum of 40% glycol (achieving a freeze protection of -6 degrees Fahrenheit). It’s important to remember that if you are adding new liquid to a loop, you will need to remove the same volume of existing liquid from the loop to make room. In addition, glycol can be harmful to the environment. Most often, it can’t be drained into the city sewer. Glycol over a certain percentage will need to be collected in drums, totes, or a tanker truck, and disposed of legally. Once the proper volume is removed, the new glycol can be added and circulated throughout the system for 6 – 24 hours.
Post Glycol Addition Sample
The most important step is to resample the loop post-addition and post-circulation to verify the new glycol percent and freeze protection.
Proactively Ensure Effective Glycol Management
Remember, the volume of the loop is always an estimate, and the quantity of glycol needed is therefore also an estimate. Additional glycol may be necessary, meaning additional liquid may need to be removed from the loop as well.
Proactive building managers will address their glycol needs during the warmer months. As temperatures drop, glycol prices increase. It’s also better to address glycol systems in the warmer months to ensure pipes are protected from freezing and cracking when the first cold days begin.
For assistance with your glycol needs contact Metro Group. Metro Group has been the trusted source for building solutions since 1925. With our water treatment experience, on-site blending capabilities for specific glycol requirements and over 10,000 gallons of glycol in stock, plus tanker truck availability we can assist in:
- Loop volume determination
- Glycol sampling for freeze protection verification
- Legal disposal of existing liquid (if needed)
- Furnishing and applying proper quantities of necessary glycol
Metro Group is your one-stop shop for all things glycol related.
Contact us today for a free lab analysis of your glycol systems to verify your current freeze protection levels.
