Available in 275 gallon tote, 55 gallon drum or 5 gallon pail, high purity DOW antifreeze is premixed with deionized water (DI water) at our in-house facility and ships out within just one business day. We sell glycol online with no accounts or order minimums required. Go Glycol Pros is a distributor of DOW® heat transfer fluid for over 20 years. Therefore, without the proper correction or adjustment to the multiplier for pumps with glycol heat transfer fluid, you may end up over pumping and wasting energy, or failing to meet the heating or cooling requirements due to under pumping. The report would indicate a lack of flow rather than the 5% additional flow that will occur. This simple example shows the balance report would be off by 10%. With the proper correction, the flow rate indicated is now 1050 GPM. If the test and balance technician uses the correct multiplier from the glycol table above, the multiplier would be 2.18.Ĥ0 PSI X 2.18 multiplier = 87.2 ft of head This would indicate we are flowing 950 GPM or 5% below the design flow rate. If concentration is unknown, we recommend you use a refractometer to measure current glycol concentration.Īssume the pump differential pressure was 40 PSI.Ĥ0 PSI x 2.31 multiplier = 92.4 ft of head The glycol concentration is known because the system fluids were purchased premixed with deionized water (DI water) from Go Glycol Pros. The heat transfer fluid is 50% Dowfrost HD (propylene glycol) at 40☏. In this example, we have a design condition of 1000 gallons per minute (GPM) at 90 feet. Table of Multipliers for Glycol Systems Propylene Glycol (DOWFROST or DOWFROST HD)ī) Chart is based on the % by volume of DOWFROST mixed with waterĬ) ®™Trademark of The Dow Chemical Company ("Dow") or an affiliated company of Dowĭoes it Make a Difference in the Test and Balance Report? In this article, we will explore an example to illustrate the importance of adjusting the multiplier based on type of heat transfer fluid.įormula to Calculate Feet of Head for Water Systemįeet of Head (Ft of Water) = (PSI X 2.31 Multiplier) / Specific Gravity Formula to Calculate Feet of Head for Glycol Systemįeet of Head (Ft of Glycol) = (PSI X Multiplier from Table Below) Since specific gravity is normally close to one for water but is not so in glycol systems, pump differential pressure gauge readings from a hydronic glycol system require an adjusted multiplier to account for the change in specific gravity.įailing to adjust the multiplier for glycol fluid may result in an assumed flow rate that doesn’t match the design, and when temperatures become really hot or cold, you may not be able to meet the occupants’ temperature requirements. However, there are times when the multiplier for the conversion of PSI to feet of head (PSI to ft head) changes. It is a simple conversion we learn early in our careers. How to Read Out the GPM of a Centrifugal PumpĪsk any HVAC test and balance technician in the hydronic system world to convert PSI to feet of water (or feet of head), and a multiplier of 2.31 is the immediate response.
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