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DESCRIPTION The FlowCon SDP series is a range of differential pressure control valves. The purpose of the valve is to keep a constant differential pressure and thereby avoid noise in the sub-system, which the valve is controlling. Further- more, the FlowCon SDP can be used as a shut off valve with FlowCon ABV housing. The FlowCon SDP insert comes in three models. Each model has a fixed differential pressure limitation of 10, 20 and 30 kPaD (1.45, 2.90 and 4.35 psid), so no need of any additional adjustment at site. The main purpose of the FlowCon SDP is to be as basic as possible, resulting in low costs and easy installation without the necessity of adjustment. This can be beneficial in many cases where fast and tamper proof solutions are preferred. Flow range, l/hr (GPM) Selection: SDP.10 SDP.20 SDP.30 DN15 / 1/2” DN20 / 3/4” DN25 / 1” Q min Q max 35 (0.154) 864 (3.80) 50 (0.220) 960 (4.23) 50 (0.220) 1420 (6.25) ACCESSORIES • ACC00110: Capillary tube with fittings for connection to FlowCon QuickDisc ® partner valve. • ACC00210: Capillary tube with fittings and adaptor for connection to FlowCon standard body taps. • ACC00121: Union M8 to 1/4” adaptor according to ISO 7.1 - compatible with FlowCon standard body taps. Tech note · FlowCon SDP · march 2024 · www.flowcon.com Page 4 of 7
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SIZING - HOW TO SELECT The FlowCon SDP valve is to be selected based on the required flow rate and the calculated differential pressure across the con- trolled circuit (ΔpC) at design flow (see flow rate table and flow curves elsewhere in this technote for reference). Δp H Δ pC Δ pBV Controlled Circuit Example: Design flow = 800 l/hr / 3.52 GPM Pipe size = DN20 / 3/4” ΔpC = 11 kPaD / 1.60 psid (design condition) Select valves (Supply and Return valves) based on line size and system requirements to eliminate pipe modifications. Δ pV Δ pC = Controlled Δ p Circuit Δ pV = Δ p across FlowCon SDP Δ pBV = Δ p across Partner Valve Δ pH = Δ p Pump Head Select FlowCon SDP insert based on required (calculated) ΔpC at design flow. From the flow curves, proper SDP model is found in the intersection between needed ΔpC and design flow. In this case find 800 l/hr (3.52 GPM) on the horizontal axis and 11 kPaD (1.60 psid) on the vertical axis. To opti- mize the system energy efficiency, select the model with closest higher ΔP at design flow compared to design condition (see flow curve next page). In this case SDP.20 will be the proper choice. SDP.20 will allow 880 l/hr (3.87 GPM) at the respective ΔpC and will thus be capable of supplying the required flow rate. Note that the maximum flow value is to be limited either on the partner valve or on the radiator thermo- stats. Determine ΔpV MIN from the dotted flow curves (see next page). In this case SDP.20 has just been selected and the dotted SPD.20 line will at ΔpC = 11 kPaD (1.60 psid) providing 880 l/hr (3.87 GPM) give a ΔpV MIN of 7 kPaD (1.02 psid). Select Partner Valve - preferably a balancing valve - and determine the ΔpBV. In this case a FlowCon QuickDisc ® , which can also limit the flow, is selected. From its specification ΔpBV is cal- culated to 2.0 kPaD (0.29 psid). Determine pump head. Calculate the minimum pump head, ΔpH using the standard formula: ΔpH = ΔpBV + ΔpC + ΔpV MIN = 2 + 11 + 7 = 20 kPaD (0.29 + 1.60 + 1.02 = 2.91 psid) FlowCon SDP.20 will hereafter ensure that the ΔpC never exceeds 11 kPaD + tolerance (1.60 psid + tolerance) and FlowCon QuickDisc ® will ensure that specified flow rate is not exceeded. Tech note · FlowCon SDP · march 2024 · www.flowcon.com Page 5 of 7
