REMOVE THE FRONT COVER AND DROP THE FRONT INSTRUMENT PANEL AFTER ISOLATING THE POWER TO THE BOILER. LOOL AT THE LOWER LEFT HAND SIDE AND YOU WILL SEE THE DIRECT HOT WATER DIFFERENTIAL PRESSURE SWITCH. A ROUND BRASS DISC WITH 6 SCREWS ROUND THE OUTSIDE, ABOUT 4 INCHES DIAMETER WITH 2 SMALL PIPES COMING OUT OF THE TOP & A MICROSWITCH ON THE FRONT OF IT. GET SOMEONE TO TURN ON A HOT TAP & CHECK THAT THE SPINDLE IN THE MIDDLE OF THE DISC COMES OUT AND CLOSES THE CONTACTS ON THE SWITCH. IF IT DOESN'T THE DIAPHRAGM WILL MOST LIKELY BE PUNCTURED. ANY DECENT BOILER ENGINEER WILL REPLACE THE DIAPHRAGM IN AROUND 20 MINUTES AND THE PART COSTS ABOUT £7 FROM ANY BOILER SPARES SUPPLIER. VERY COMMON FAULT ON THIS BOILER.
DAVE12, April 2007
