Draining the system to fix a shower

[swebb99]

My mother has an old Aqualise Aquavalve shower which is dripping, its about 40yrs old. I've had a look and it would seem that replacement cartridges are still available I just need to figure out which one I need as I believe its a manual cartridge rather than a thermostatic cartridge. My issue is how do I first make sure that water doesn't come flooding out of the shower when I open it up. My mother still has an old glowworm boiler fitted and a hot water tank. I think this is fed by a water tank in the loft. I can certainly hear water filling the tank in the loft after a shower. I can only find a tap to cut off water to the house in the garage and no other cut off valves. If I turn off the boiler and the hot water tank should I be safe to run the hot water from the bathroom sink or shower and also the cold water until no water comes out. After replacing the cartridge and seals turning the taps off and opening the main tap again. Will everything fill as expected or do I risk some kind of air lock in the hot water tank for somewhere else. Thanks.

 

[denso13]

Turn off the cold, then turn off any valve feeding the cistern in the loft or tie the ball up if none. Open hot and cold till they stop running. Turn everything back on when you're done, it may airlock, but usually doesn't, normally an easy fix if it does.

 

[swebb99]

Great thanks