ecoTEC exclusive installation and maintenance instructions / 0020017768_0424• Repeat this at all radiators until the complete systemis full, all air locks have been cleared and the boilerpressure gauge reads 1.5 bar. Release any air fromthe pump by slackening the centre screw. Turn offthe filling valve (2) and fully close filling valve (1).• The boiler is equipped with an automatic air releasevalve. To allow this to vent the boiler, the cap on thetop must be slackened by 1 –2 turns (This cap must beleft slackened during boiler operation to ensure anyresidual air or system gases are released).• Check the heating system and boiler connectionsare sound.h Note!Use the test programme P.0 to vent the boilerand the heating system: The unit does not startin heating mode, the heating pump switches onand off and alternately vents the heating cir-cuit and the hot water circuit, see Chapter 9.2.6.1.2 First flushing of the systemh Note!The entire heating system must be flushedthrough completely at least twice: once coldand once hot, in accordance with the followinginstructions.• Check if all radiator thermostat valves and bothmaintenance cocks on the boiler are open.• Connect a hose to the drain valve which is locatedat the lowest position in the heating system.• Open the 1/2" KFE drain cocks and all the vent valveson the radiators so that the water flows quickly andcompletely out of the heating system and the boiler,in order to remove the contamination caused duringthe installation out of the heating system before theboiler is started up.• Close the 1/2” KFE drain cocks.• Re-fill the heating system with water as describedin Section 6.1.1.• Check that the over-pressure valve in the heatingsystem is functioning correctly by turning the handleon the valve.• Check the pressure in the heating system and topup with water if necessary.• Close filling valve 1 and filling valve 2.6.1.3 Filling and venting from the hot water side• Open the cold water stop cock on the appliance onthe inlet combination.• Fill the hot water system by opening all the hot watertaps until water comes out.• As soon as water comes out of all the hot water taps,the hot water circuit is filled completely and also vented.6.1.4 Filling the condense trap1Fig. 6.4 Filling the condense trapd Danger!If the appliance is started up with an unfilledcondense trap, there is a danger of poisoningby exhaust gas emission.Fill the trap as follows:• Unscrew the lower section of the trap (1) from thecondense trap.• Fill the lower section of the trap (1) 3/4 full with water.• Screw the lower section of the trap back onto thecondense trap.6.2 Checking the gas settinga Caution!Conversion from natural gas to liquid gas orvice versa may only be undertaken by Vaillantservice personnel or a suitably qualified install-er approved at the time by the Health and Safe-ty Executive.h Note!For all kind of conversions a special Vaillantconversion kit is needed. Further informationcan be obtained from Vaillant Service Solutions(0870 6060 777).6.2.1 Gas pressure statement - Natural gasa Natural gas:Do not proceed with the adjustment or attemptto put the unit into service if the inlet workingpressure lies outside the 19-23 mbar range.The nominal operating pressure at the gas meter outletshould be between 19 and 23 mbar. The gas valve withinthe appliance is factory set for Natural Gas G20 andshould need no adjustment. The appliance is designed tooperate with an inlet pressure to the appliance of6 Start-up