You can have two electric showers in your home.You should have an electrician fit a device called a relay which ensures that only one shower can be used at a time.
If a leak occurred while your away it could do a lot of damage, especially if your away for a long period.
It is true, but practically nobody does it in the Dublin area.
Yes you need to have it replaced immediately, that valve cannot be blocked while the boiler is being used.Pressure can build and cause a burst, releasing boiling water.
There is a good chance its trapped in the u-bend, if you dismantle it carefully and empty the contents into a basin you might be lucky. Make sure to refit the u-bend correctly.
