Hi ive just changed a bathroom suite on a bungalow that has a sealed hot water cylinder. The plumbing in the house is old including the cylinder. When turning the hot water back on the hot water dousnt maintain pressure. When turning the hot water taps on their is a sudden burst of mains pressure wich the dwindles in to a very low pressure run. Any ideas on what is causing this and how to rectify. Cheers J