In our extended shower down stairs we fix thermostat shower valve. From few weeks it's makes noise when I run hot water in upstairs shower it's starts making sound. When we finish using the upstairs shower noise stop. And one more problem our boiler shows flame loss because of this. When I turn on central heating after making reset the boiler it doesn't gave any problem at all with the boiler but shower valve makes noise every time we use the other shower. Can anyone help me out with this problem.
Could be some sort of air lock or loose pipe. Check that first, if not Could try non return valves on feed to shower.
Sounds like the usual.. Plumbed wrong way round on hot n cold, you certain its' piped up right ? If so try another valve never know might be faulty unit