My flat is too high (4 floors) for Thames Water mains pressure. The builder fitted the above pump about 8 years ago. It now periodically 'dries up' and then eventually recovers, but for 10 or 15 minutes (usually mid-shower) no water is available. Arrow Valves tells me the solenoid valve needs replacing, but they are not able to send a technician until mid-July. They have advised me to order the valve (which I have done) and find a local tradesperson to fit it. But, so far I have been unable to find such a person. The pump and valve in question can be seen here: www.arrowvalves.co.uk/downloads_ss/btafcompactboosterseto&mmanual.pdf (valve on page 4). Is this rocket science? Could I replace this valve? Does it have to be done by a technician registered with some sort of qualification or can any reasonably competent person with a screwdriver do it? With thanks, as always, for any advice, EL.