Isolate shower to service valves

[Enthusiastictrier81]

Hi All, new here and need some help. I’ve just bought a house with a built in Mira 915b shower. The valves are playing up so I want to remove them to put new o rings and grease on. Trouble is I can’t isolate the water to it. Hot is fed from the cylinder and the feed has a gate valve which is stuck. Cold is fed from the header tank and has no isolation or gate valve. I tried turning the mains water off and running the shower to see if emptying the header tank would stop both hot and cold but it just ran on for 20 minutes before I gave up. Any suggestions to help? Really need to sort these valves out.

 

[Maryplumb]

You will need to turn off heat to cylinder, and drain the tank via something with more flow, like a cold bath tap or sink tap. Make sure you get the proper service kit from Mira and allow time for dismantling shower. Best to put isolating valves on the pipes while you are at it for future use. If in a flat, or if an old tank, be prepared for airlocks when refilling and leave off the heat to the cylinder until flowing freely from a hot tap. Care needed as well as enthusiasm!