hello i have a chaff britony 80 and believe the flexi hose is clogged up with sludge again,,,it did exactly the same thing around six months ago,,,pressure going right up then dumping out the overflow,,,plumber came and just cleaned out the flexi pipe and all has been fine since until today,,,unfortunatley i didnt take much notice to how he did this so can someone give me a simple step by step guide to remove and replace the flexi hose please......