Had a new toilet installed. Problem is that the toilet sometimes won't flush and I have to take off cistern cover and move the 'thingy' manual to get the cistern to fill up.
Then I cant stop the cistern from filling.
Toilet installed 5 days ago-
Has it been installed incorrectly or is it a faulty toilet?
No way to know for sure but your plumber should have noticed this - put it down to a faulty plumber
The valve might just need a simple adjustment but I'd get the plumber to do it to be on the safe side (especially if it's an upstairs toilet, where leaks can be expensive).
The ball float is probably catching on the side of the cistern or there may be some debris in the valve, easily rectified -if you know what you're doing and have the confidence to approach it. Otherwise call back your plumber.
I'll bet it's one of those silent valves, perhaps a Cisternmaster or similar- cube shaped float rises vertically around a central pipe? If so the valve just needs some adjustment as these valves don't fit every cistern.