Baxi 105e, usual problem, central heating getting hot when hot tap is on. CH did have some crud in it, this has now been flushed. Still need to fix the diverter valve. Can these be stripped down and cleaned? If so, do i need some new seals on reassembly? Or is it just not worth it and I should get a new valve? What i really want to avoid is stripping it down on friday afternoon, then finding that something in it needs replacing and having no hot water for the weekend.