i think its because when you turn on the hot water tap the dirt in the tap has gone because the dirt loses the stickiness and hot water gets rids of stickiness
Check the heating elements in the water heater. These may be bad and need replaced.
There will obviously be corrosion so if the water is meant for drinking (some people pour hot water into their kettles/pots to reduce boil time), washing dishes/clothes then no, but if it is purely for hot water and not needed for these general uses then it's possible but not advised - especially from a maintenance point of view.
air lock in hot water pipe
No, cold water is piped into the hot water tank and is heated by electricity or gas, it then flows out to the hot water taps.
Assuming a single boiler, if some location is not getting cold water either a valve is closed or a line is blocked with mineral deposits.
If the tub is not getting hot water the issue is probably with the hot water heater. The hot water heater may have tripped a breaker or the pilot light went out.
Because you're in it.
If you have no hot water, your heating element is out most likely
Hot water
no !
By refrigerating it.
It is probably sediment from the hot water heater, you may need to flush out the hot water heater tank, all it takes is a garden hose.
Because it is getting to hot for them they have no water
If the water is hot, the answer is a burned up black dude
Install a spirovent
you give it a rub under hot water
So the radiation from the sun is absorbed by the black surface to heat the water in the pipes.