Nimbus Compact M NET R32 Installation Manual UK

Hydraulic connections

Hydraulic connections – discharges at high level: e.g. into a metal hopper and metal downpipe with the end of the discharge pipe clearly visible or onto a roof capable of withstanding high-temperature discharges of water and 3 m from any plastic guttering system that would collect such discharges. – The discharge would consist of high-temperature water and steam. Asphalt, roofing felt and non-metallic rainwater goods may be damaged by such discharges. Discharge pipe (D2) characteristics – The discharge pipe (D2) should be made of metal or other material with proven capacity to safely withstand the high temperatures of the water discharged (above 95°), and be clearly and permanently marked to identify the product and its performance rating. – The discharge pipe (D2) should be at least one pipe-size larger than the nominal outlet size of the safety device, unless its total equivalent hydraulic resistance exceeds that of a 9 m-long straight pipe, i.e. for discharge pipes between 9 m and 18 m long, the equivalent resistance length should be at least two sizes larger than the nominal outlet size of the safety device; between 18 m and 27 m, it should be at least 3 sizes larger, and so forth; bends must be taken into account when calculating the flow resistance. Typical discharge pipe arrangement 1 600 mm Maximum 2 300 mm Minimum 4 3 5 6 Fig. 48 1 Safety device (e.g. temperature relief valve) 2 Metal discharge pipe (D1) from the temperature relief valve to the tundish 3 Tundish 4 Discharge pipe (D2) from the tundish, with continuous fall. (refer to “Connection of the discharge pipe (D2) to the tundish” in paragraph Safety device connection, the table below and the worked example) 5 Fixed grating 6 Trapped gully Discharge below fixed grating (see figure above). Sizing of copper discharge pipe (D2) for common temperature relief valve outlet sizes: Valve outlet size G1/2 Minimum size of discharge pipe D1 15 mm Minimum size of discharge pipe D2 from 22 mm tundish 28 mm 35 mm Maximum allowed resistance, expressed as the length of a straight pipe (i.e without elbows or bends) Resistance generated by each elbow or bend Up to 9 m Up to 18 m Up to 27 m 0.8 m 1.0 m 1.4 m Worked example The example below is for a G½ temperature relief valve with a discharge pipe (D2) having 4 x 22 mm elbows and a 7 m length from the tundish to the point of discharge. – From the above table, the maximum allowed resistance for a straight length of 22 mm copper discharge pipe (D2) from a G½ temperature relief valve is: 9.0 m; – Subtract the resistance for 4 x 22 mm elbows at 0.8 m each = 3.2 m; – Therefore, the maximum allowed length amounts to 5.8 m, which is less than the current length of 7 m, so calculate the next largest size; – Maximum allowed resistance for a straight length of 28 mm copper discharge pipe (D2) from a G½ temperature relief valve is: 18 m; – Subtract the resistance for 4 x 28 mm elbows at 1.0 m each = 4 m; – Therefore, the maximum allowed length amounts to: 14 m; – Since the current length is 7 m, a 28 mm (D2) copper pipe will do. a The outlet from the temperature and pressure relief valve and expansion relief valve must not be used for any other purpose. The temperature and pressure relief valve must not be removed under any circumstances. 4.2.5 Hydraulic connections Description Connection Type Connection Size T&P discharge Male G 1/2 Safety inlet assembly: Safety valve Compression D 15 Exp. vessel inlet Famale 3/4” inlet Cold mains water Compression 22 mm Cylinder outlet Compression 23 mm Expansion vessel Male 3/4 Gas a The installer must verify and provide evidence of conformity with respect to the following regulations: – The Building Regulations 2010 (S.I. 2010 No. 2214), as amended; – The Water Supply (Water Fittings) Regulations 1999 (S.I. 1999 No. 1148), as amended. 30 / EN

Hydraulic connections 4.3 Example of schematic hydraulic diagram 1 ZONE FS AB B A OR A B AB Fig. 49 OR HV IN 1 HV IN 2 OUT AUX 4 OUT PM AUX V1 V2 AUX 3 N L LC N LO LC N LO L1 L2 L3 N 3ph L2 L’ L1 N’ L1 L2 L3 L3 N N 1ph STT S G OR EH1 EH1 ST1 ST1 L N EH1 EH1 ST1 ST1 L1 L2 L3 N IN G GND BUS +24 V GND RL FB STH +24 V GND S01 OPEN ATG BUS DHW HEATER ANODE EBUS2 IN IN AUX B T 2 STE TA1 TA2 SE TNK BUF THERM AUX 1 OUT OUT AUX 2 AUX 1 1ph 3ph Fancoil: Z0 OR Underfloor Heating: Z1 CHILLER BOILER Fancoil: Z1 a a i Fig. 50 It is forbidden to disconnect the power supply to the unit if the outdoor temperature can fall below ZERO (risk of frost). Drain the central heating and domestic hot water systems to prevent the risk of ice forming. Do not remove the heating delivery temperature sensor (inside the heating elements). Carry out the electrical connections after having completed all the hydraulic connections. EN / 31