Halstead BFF40 Instructions For Use Installation And Servicing

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Halstead BFF40 Instructions For Use Installation And Servicing Manual pdf 8 page image

82000225095BDiagram 2.2FULLY PUMPED SYSTEM(DIAGRAMMATIC)2 Water Systems08701 metreMIN.27metresMAX.PUMPHeatingCircuitTO INDIRECTCYLINDER22mm VENT15mmCOLD FEEDDistributor tube inpumped returnconnectionBOILERCLDRAIN OFFCOCK2.1 Water Pressure HeadThe boiler shall only be connected to a cistern water supply witha minimum head of 1metre (3ft3in) and a maximum head of27metres (90ft) which has an open vent in the system.The working pressure must be within the range 0.1bar to 2.7bar(1.3 to 39lbftin 2).The boiler MUST NOT be connected to a sealed water system.2.2 InhibitorAttention is drawn to the current issue of BS5449 and BS7593on the use of inhibitors in central heating systems.If an inhibitor is to be used in the system, contact should bemade with the inhibitor manufacturers so that they canrecommend their most suitable product.When using in an existing system take special care to drain theentire system, including the radiators, then thoroughly clean outbefore fitting the boiler whether or not adding an inhibitor.2.3 Gravity Domestic and Pumped HeatingIt is recommended that a cylinder thermostat is used to preventthe stored water temperature becoming unnecessarily highwhen the central heating pump is off.The domestic primary flow and return must be 28mm o.d. Theinstallation must comply with the current issue of BS5546 andBS6700, see diagram 2.1.If the above conditions cannot be met, it is suggested that a fullypumped system be used.2.4 Pumped Heating and Hot WaterWhere a single flow and return is taken from the boiler, aminimum static head of 1metre (3ft3in) must be providedbetween the water line of the feed tank and the centre of thewaterway, see diagram 2.2.2.5 Circulation PumpNormally the pump should be set to give a temperature differenceof 11 oC (20o F) across the boiler. At the appropriate pumped flowrate the pressure loss through the boiler can be found from thegraph, diagram 2.3.Use a pump with integral valves or fit isolating valves as closeto the pump as possible.2.6. CylinderFor all systems supplying domestic hot water the cylinder mustbe indirect.2.7 Safety ValveA safety valve need not be fitted to an open vented system.2.8 Draining TapA draining tap must be provided at the lowest points of thesystem which will allow the draining of the entire system,including the boiler and hot water cylinder.Draining taps should be to the current issue of BS2879.2.9 Thermostatic Radiator ValvesIf thermostatic radiator valves are fitted care must be taken toensure that there is an adequate flow rate through the boilerwhen they close, refer to the current issue of BS7478 forguidance. If fitted to all radiators ensure a bypass is fitted andadjust to achieve a temperature difference no greater than 20o Cbetween flow and return with the thermostatic valves closed.Diagram 2.1086927metresMax.PUMPHeatingCircuitINDIRECTCYLINDER(Shown withrecommendedthermostat and valve).22mm VENT15mm COLD FEEDREFER TO BS 554628mmDistributor tube inpumped returnconnectionBOILERCLDRAIN OFFCOCKDiagram 2.308726005004003002001000128400 4 8 12 16 20 24 28FLOW RATE (LITRES/MINUTE)WATER PRESSURE LOSS(mm HEAD OF WATER)WATER PRESSURE LOSS(INCHES HEAD OF WATER)2416800 3228207000 1 2 3 4 5 6FLOW RATE (GALLON/MINUTE)