turn off boiler (at 3amp spur) turn both flow and return pipe isolating valves (beneath the boiler) to the off position.
Drain all water from the boiler via the drain cock (behind the pump) then test and recharge your expansion vessel as required.
When refilling the boiler, make sure to bleed the pump and ony run the pump (keep switching the boiler off before it fires) until the sloshing water noise abaits (ie all the air os out of the boiler) before firing
remeber to top up your system water back to 1-1.5 bar after you refill the boiler and bleed of the uppermost rads in the house.
T, April 2008
