TURBOmax VUW 282 E - Heatingspares247.com

7. Parts replacementIMPORTANT:Before starting any maintenancework:• Isolate the mains electricity supplyby disconnecting the plug at thesocket outlet (if there is an isolatingswitch only, remove the fuse fromthe switch).• When removing any water carryingcomponents ensure that the controlbox cover and terminal box coverare in position and water is keptaway from all electricalcomponents.• Turn OFF the gas supply at the gasservice valve fitted to the boiler.• Always test for gas soundness andalways carry out functional checksafter any service work and afterexchanging any gas carryingcomponent.• Always check earth continuity,polarity and resistance to earth witha multimeter after any service workand after exchanging any electricalcomponent.7.1.2 Releasing CH water pressureand draining the boiler (fig. 50)• Isolate electrical supply to boiler.• Remove combustion chamber coveras in section 7.1.5.• Turn off boiler CH service valves(2).• Attach a length of rubber tube todraining points (4), and drain thewater from the boiler into asuitable container by undoing thedrain points one turn.• When pressure gauge reads zero,open main heat exchanger air vent(5, fig. 57) to allow completedraining of the boiler. Close airvent before refilling the boiler.fig. 50GW 619/07.1 Initial preparation(These initial preparation proceduresneed only be carried out wherespecifically mentioned in the individualcomponent replacement procedures).7.1.1 Turning off the boiler (fig. 50)• Isolate the electrical supply to theboiler• Turn off the gas service valve (1)• Turn off boiler CH service valves (2)• Turn off DHW cold water servicevalve (3).32