No pressure in the hot water in all house?

Check your water heater to ensure that the valve in the supply line is open. You can test that the water heater is working by using the relief valve at the top, just beware of the potential for scalding hot water to come out if the heater is operating correctly. If you have a full tank, and all the valves are open around the water heater, it may be time to call a plumber.