Question:
My step son drained the hot water heater (gas). Now the water pressure for the hot water is very low. Cold is fine. There was no problem before it was drained. Possibly the incoming or outgoing valve is not open all the way. After that I don’t know.
Answer:
Sometimes sediment will be stirred up when you drain a water heater and block the cartridges inside the faucets. Also, if your shut off valve to the water heater is an old fashioned “gate valve”, it is probably broken in a partially open position. You should replace it as a precaution. Any time a water heater is flushed, always open the bathtub faucet first, as there is no aerator to cause a back pressure (which can trap sediment in the valve). Also, do not flush a water heater that is more than 3 or 4 years old if you have not been doing it since day one when it was installed.