9i combi - Installation and ServicinggeneralaIR sUppLyIt is NOT necessary to have a purpose-provided air vent in theroom or internal space in which the boiler is installed. Neitheris it necessary to ventilate a cupboard or compartment in whichthe boiler is installed, due to the low surface temperatures of theboiler casing during operation; therefore the requirements of BS6798, Clause 12, and BS 5440:2 may be disregarded.WaTER CIRCULaTION sysTEMIMpORTaNT.A minimum length of 1 metre of copper pipe MUST be fittedto both flow and return connections from the boiler beforeconnection to any plastic piping.The central heating system should be in accordance with BS.6798and, in addition, for smallbore and microbore systems, BS.5449.WaTER TREaTMENT - see Frame 4bOILER CONTROL INTERLOCKsCentral heating systems controls should be installed to ensurethe boiler is switched off when there is no demand for heating, incompliance with Building Regulations.Heating systems utilising full thermostatic radiator valve controlof temperature in individual rooms should also be fitted with aroom thermostat controlling the temperature in a space served byradiators not fitted with such a valve.When thermostatic radiator valves are used, the space heatingtemperature control over a living / dining area or hallway havinga heating requirement of at least 10% of the minimum boiler heatoutput should be achieved using a room thermostat, whilst otherrooms are individually controlled by thermostatic radiator valves.However, if the system employs thermostatic radiator valves on allradiators, or two port valves, then a bypass circuit must be fittedwith an automatic bypass valve to ensure a flow of water shouldall valves be in the closed position.ELECTRICaL sUppLyWarning.This appliance must be earthed.Wiring external to the appliance MUST be in accordance withthe current I.E.E. (BS.7671) Wiring Regulations and any localregulations which apply. For IE reference should be made to thecurrent ETCI rules for electrical installations.The mains supply to the boiler and system wiring centre shallbe through one common fused double pole isolator and fornew heating systems, and where practical replacement boilerinstallations, the isolator shall be situated adjacent to theappliance.CONDENsaTE DRaINRefer to Frames 21, 22 & 37A condensate drain is provided on the boiler. This drain must beconnected to a drainage point on site. All pipework and fittings inthe condensate drainage system MUST be made of plastic - noother materials may be used.IMpORTaNT.Any external runs must be in accordance with BS 6798.The drain outlet on the boiler is sized for standard 21.5mm (3/4”)overflow pipe. It is a universal fitting to allow use of differentbrands of pipework.