Usually because there's a kink in your main valve. You need to hire someone immediately if this happens, because it could flood your house.
Temperature is too high or the valve is bad.
an arm
typically these two problems are caused by two different things. A running toilet is most commonly caused by a leaking flapper (when you push down on the flush handle a chain lifts the flapper and lets the water escape the tank and "flush' into the bowl.) a water spurt is usually caused by a faulty fill valve (the part in the tank that attaches to the water supply and fills the tank after it is flushed.) with an 8 year old toilet both of these parts would most likely be worn out, either thru age or use. T Line
since check valve holds water in the line can a hand pump be installed between the check valve and water tank?
That is a fill valve and is part of the ballcock system. When someone pulls the lever, that pulls the chain and lifts the flush valve flapper and empties the tank into the bowl. That causes the float to drop, opening the fill valve and allowing water from the supply to enter and refill the tank.
If you have a leak on the hot water somewhere in the house and the water input into the tank is not running, the tank will lose it's water. And if it is an electric tank, the elements will burn out. Gas hot water tank should be no problem. Pressure valve does not have to be open.
There is a shutoff valve on the cold pipe going into the H/W tank, if you close it no water will come out of the tank. There should also be a shutoff valve on the wall below each faucet/tap.
First check to see if the valve for the water supply is turned on. If that isn't the problem you may need to replace the tank water valve, they do wear out and are not that expensive or difficult to replace.
You can prevent back flow of water from your tank by installing a back flow restrictor valve. The restrictor valve will allow fluid to flow in one direction.
It is a small, valve usually used to manually check if water is above the valve connection on a boiler or tank. There may be several of them at different heights on the boiler or tank. There is a handwheel on the valve, an inlet connection (which is attached to the boiler) and an outlet (usually left unconnected). When filling the boiler or tank, the try-cocks can be left open. Water coming from the try-cock means the tank is filled to at least that level. The valve is then closed.
Install a tempering valve in water line feeding toilet. Tempering valve will mix hot and cold water together so warm water fills toilet tank which will stop condensation.
The water supply line attaches to it on the bottom of the tank. The actual valve is at the top of this tube.