Can the Orturi UltraXB flow chart be used in conjunction with a Nexus AY coil pak?

Answer 1

The short answer to your question is no. The flow chart for the UltraXB Orturi TM is based upon the Cv values for the UltraXB.

The UltraXB Orturi is a fixed orifice device with a set Cv value. (Cv is the amount of water that will flow through the orifice, in GPM, with a 1 PSI pressure drop.)

To use the UltraXBTM one would take a pressure drop reading across the orifice and adjust the handle to achieve the required pressure drop for the desired flow rate using the flow chart in question.

The Nexus AY Coil Pak uses the UltraMaticTM to regulate the water flow. The UltraMaticTM is an Automatic Flow Control Valve (AFCV). Automatic Flow Control Valves work over a differential pressure range (2 - 45 PSID for the UltraMaticTM.) When checking the flow on an AFCV, simply test the differential pressure across the valve; if the Delta P falls within the operating range of the valve, then you are achieving the specified flow rate. No need for charts and no need for adjusting.

AFCVs are ordered for a specific flow rate and cannot be adjusted. However, if a flow rate was selected incorrectly, the flow control cartridge can be changed for the correct flow rate very easily.

Using an AFCV like the UltraMaticTM is a brilliant solution for hydronic balancing. Specifying and using this product provides several benefits:

• Fewer balancing valves are required for the system reducing the cost of the materials.
• System is "Balanced" at start-up reducing costly balancing labor.
• Because the system is balanced, VFDs can control the pumps reducing energy consumption due to over pumping that occurs with manual flow control valves.
• Chillers and Boilers operate more efficiently due to balanced flows avoiding Low Delta T syndrome.
• Fewer call backs due to occupant comfort issues means satisfied clients and return customers.