Application AVP is a self-acting differential pressure control that closes on rising differential pressure. AVP is primarily used in block and district heating systems. The control has external threads for heating system connection. Weld-on tailpieces and tailpieces with external threads are available as accessories. The control is supplied complete with compression fittings for connecting Ø6 mm copper impulse tube. Differential pressure control AVP-F with a fixed differential pressure of 0.2 or 0.3 bar are available on request. Principle Fig. 1 Direct-connected heating system Fig. 2 Indirectly connected heating system SIBC R&D VD.55.L4.02 Danfoss 6/98 1
Ordering Complete control with compression fittings for impulse tube connection Setting range: 0.2-1.0 bar Setting range: 0.05-0.5 bar External Typ DN thread 1) k v Code No. 2) k v Code No. ISO 228/1 m 3 /h m 3 /h AVP 15 15 G ¾ A 1.6 003H2026 1.6 003H2021 AVP 15 15 G ¾ A 2.5 003H2027 2.5 003H2022 AVP 20 20 G 1 A 4.0 003H2028 4.0 003H2023 AVP 25 25 G 1¼ A 6.3 003H2029 6.3 003H2024 AVP 32 32 G 1½ A 10.0 003H2030 10.0 003H2025 1) X P = 0.15 bar 2) X P = 0.10 bar 1 set of accessories including 2 tailpieces, 2 union nuts and 2 seals Weld-on tailpieces Tailpieces with external threads DN Code No. Code No. 15 003N5090 003N5070 20 003N5091 003N5071 25 003N5092 003N5072 32 003N5093 003N5073 Spare parts Spare parts Code No. 10 compression fittings for impulse tube 003H2300 Adjustment section 0.05-0.5 bar and diaphragm 003H2301 Adjustment section 0.2-1.0 bar and diaphragm 003H2302 Valve insert, k vs = 1.6 m 3 /h 003H2310 Valve insert, k vs = 2.5 m 3 /h 003H2311 Valve insert, k vs = 4.0 m 3 /h 003H2312 Valve insert, k vs = 6.3 m 3 /h 003H2313 Valve insert, k vs = 10.0 m 3 /h 003H2314 Design 1. Valve body 2. Type label 3. Valve insert 4. Spindle 5. Pressure relief cylinder 6. Union nut 7. Control diaphragm 8. Compression fittings for impulse tube 9. Diaphragm section 10. Setting spring 11. Handle 2 VD.55.L4.02 Danfoss 6/98 SIBC R&D
Materials, parts in contact with water Valve body:... RG 5, DIN 1705, W.no.2.1096.01 Valve insert:... Dezincing-free brass,... BS 2874 Valve cone:... Dezincing-free brass,... BS 2874 Valve plate:... EPDM Valve seat:... CrNi steel, DIN 17440, W.Nr. 1.4404 Pressure reliefcylinder:... CrNi steel, DIN 17440, W.Nr. 1.4404 O-rings:... EPDM Springs:... CrNi steel, DIN 17224, W.Nr. 1.4568 Diaphragm body:zinc chromatic steel,... DIN 1624, W. Nr. 1.0338 Diaphragm:... EPDM Data Pressure stage PN 16 Max. differential pressure 12 bar Max. water temperature 140 C Cavitation factor z 0,6 1) Water for district heating and central heating Medium systems, according to VDI 2035. Glyconic water resistant down to 30 C Medium ph Min. 7, Max. 10 1) k v k vs 0, 5inDN25andDN32 versions Adjustment Relation between scale figures and differential pressure. Values given are approximate Fitting The control must be mounted in the heating system return. The positive wire must be fitted in the mixing circuit flow of direct-connected heating systems (fig. 1) and in indirecly connected systems (fig. 2) ahead of the control valve in the direction of flow. The negative wire is integrated in the valve. The control can be fitted in any position. Further fitting details are described in the instruction accompanying the product. SIBC R&D VD.55.L4.02 Danfoss 6/98 3
Sizing Example 1 Motor valve for mixing circuit in directconnected heating systems requires differential pressure of 0.1 bar (fig. 1 and 3) Given: Q max p min p circuit p motor valve p AVP p AVP = 350 l/h (0.35 m 3 /h) = 0.7 bar (70 kpa) = 0.1 bar (10 kpa) = 0.1 bar (10 kpa) = p min p motor valve = 0.7 0.1 = 0.6 bar (60 kpa) Possible pipe pressure losses are not included. k v value is calculated according to formula: Qmax 035. k v = = =. m / h pavp 06. 05 3 or read from sizing diagram by taking a line through Q-scale (0.35 m 3 /h) and p v scale (0.6 bar) to intersect k v -axis at 0.5 m 3 /h. Solution: The example selects AVP 15 with setting range 0.05-0.5 bar, X p = 0.02 bar, k v = 1.6. At 0.1 bar control setting AVP varies from 0.1 bar at open valve and 0.1 + 0.02 = 0.12 bar at closed valve. Q max p min p Circuit p avp p Motor valve Example 2 Motor valve for indirectly connected heating systems requires differential pressure of 0.5 bar (50 kpa) (fig. 2 and 4) Given: Q max = 1.25 m 3 /h p min = 1.0 bar (100 kpa) p exchanger = 0.05 bar (5 kpa) p motor valve = 0.5 bar (50 kpa) p AVP = p min p exchanger p motor valve p AVP = 1.0 0.05 0.5 = 0.45 bar (45 kpa) k v value is calculated according to formula: Qmax 125. k v = = =. m / h pavp 045. 19 3 or read from sizing diagram by taking a line through Q-scale (1.25 m 3 /h) and p v scale (0.45 bar) to intersect k v axis at 1.9 m 3 /h. Solution: The example selects AVP 15 with setting range 0.2-1.0 bar, X p = 0.07 bar, k v = 2.5. At 0.5 bar control setting AVP varies between 0.5 bar at open valve and 0.5 + 0.07 = 0.57 bar at closed valve. Possible pipe pressure losses are not included. Q max p min p Exchanger p avp p Motor valve 4 VD.55.L4.02 Danfoss 6/98 SIBC R&D
Sizing Select suitable control size and P-band (X p ) not exceeding 50% of the set control differential pressure. SIBC R&D VD.55.L4.02 Danfoss 6/98 5
Dimensions H L 1 L 2 L 3 mm mm mm mm ISO 228/1 DN 15 33 139 131 65 G ¾ A DN 20 33 154 142 70 G 1 A DN 25 37 159 159 75 G 1¼ A DN 32 37 184 196 100 G 1½ A Nipple for impulse tube 6 VD.55.L4.02 Danfoss 6/98 SIBC R&D