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NUOS Plus - User Manual

  • Text
  • Appliance
  • Heater
  • Heating
  • Installation
  • Operating
  • Discharge
  • Maintenance
  • Electrical
  • Technical
  • Regulations
  • Nuos
  • Manual

Heat pump water heater -

Heat pump water heater - TECHNICAL INFORMATION FOR INSTALLERS The 250I version has an indirect coil that is intended for connection to a water heating system, such as a boiler as show below. A manual reset overheat stat is supplied fitted to the product. This stat should be wired so that in the event of over temperature in the product’s hot water system the thermostat breaks the electrical supply to the motorized valve which in turn mechanically closes preventing primary water entering the coil. The overheat setting fro the stat should be set at a maximum temperature 70°C TPRV & PRV Discharge: The discharge from the cylinder TPRV and combination PRV must be plumbed to the tundish and should not be used for any other purpose. The tundish must be vertical and fitted within 750mm of the pressure relief valve and must be located with the Nuos. The tundish must be in a position visible to the occupants, and positioned away from any electrical devices. The discharge pipe from the tundish should terminate in a safe place where there is no risk to persons in the vicinity of the discharge, and be made of a suitable material in line with Building Regulation G3 (preferably metal). The tundish must not be located near or above electrical components, switches or junction boxes. TPRV & PRV Discharge Pipes – To Gully: The discharge pipes from safety devices (tundish) must be installed to fully comply with Part G3 of the Building Regulations (latest edition). The following text, and diagram 1 are reproduced from G3 Building Regulations 2010 (as amended) Draft. BUILDING REGULATIONS G3 (the following text is reproduced from the Building Regulations. It is included here for reference only). These are a statutory document and take priority over all other regulations and recommendations. The installation of an unvented hot water system of over 15 litres is classified as a “Controlled Service” and Regulation G3 applies. To meet the requirements of the regulation, installation of an unvented system should be undertaken by a “competent installer”. All installations of unvented hot water storage systems having a capacity of more than 15 litres should be notified to the relevant Local Authority by means of building notice 10 or by the submission of full plans. It is important to note that it is a criminal offence to install an unvented hot water storage system over 15 litres without notifying the Local Authority. Discharge pipes from safety devices Discharge pipe D1 3.50 Safety devices such as temperature relief valves or combined temperature and pressure relief valves (see paragraphs 3.13 or 3.18) should discharge either directly or by way of a manifold via a short length of metal pipe (D1) to a tundish. 3.51 The diameter of discharge pipe (D1) should be not less than the nominal outlet size of the safety device, e.g. temperature relief valve. 3.52 Where a manifold is used it should be sized to accept and discharge the total discharge from the discharge pipes connected to it. 3.53 Where valves other than a temperature and pressure relief valve from a single unvented hot water system discharge by way of the same manifold that is used by the safety devices, the manifold should be factory fitted as part of the hot water storage system unit or package. 3.54 The tundish should be vertical, located in the same space as the unvented hot water storage system and be fitted as close as possible to, and lower than, the safety device,with no more than 600mm of pipe between the valve outlet and the tundish (see Diagram 1). Note: To comply with the Water Supply (Water Fittings) Regulations, the tundish should incorporate a suitable air gap. 15

Heat pump water heater - TECHNICAL INFORMATION FOR INSTALLERS 3.55 Any discharge should be visible at the tundish. In addition, where discharges from safety devices may not be apparent, e.g. in dwellings occupied by people with impaired vision or mobility, consideration should be given to the installation of a suitable safety device to warn when discharge takes place,e.g. electronically operated. Discharge pipe D2 3.56 The discharge pipe (D2) from the tundish should: a. have a vertical section of pipe at least 300mm long below the tundish before any elbows or bends in the pipework (see Diagram 1); and b. be installed with a continuous fall of at least 1 in 200 thereafter. 3.57 The discharge pipe (D2) should bemade of: a. metal; orb. other material that has been demonstrated to be capable of safely withstanding temperatures of the water discharged and is clearly and permanently marked to identify the product and performance standard (e.g.as specified in the relevant part of BS 7291-1:2006 Thermostatic pipes and fittings forhot and cold water for domestic purposesand heating installations in buildings.General requirements). 3.58 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 straight pipe 9m long, i.e. for discharge pipes between 9m and 18m the equivalent resistance length should be at least two sizes larger than the nominal outlet size of the safety device; between 18 and 27m at least 3 sizes larger, and so on;bends must be taken into account in calculating the flow resistance. See Diagram 1, Table 3.1 and the worked example. Note: An alternative approach for sizing discharge pipes would be to follow Annex D, section D.2 of BS 6700:2006 + A1:2009 Specification for design, installation, testing and maintenance of services supplying waterfor domestic use within buildings and their curtilages. 16

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