I replaced the anode in my hot water heater. The tank filled slow and now the pressure bleeds off fast. The cold water still has good constant pressure. I could not shut the fill valve off, the knob just spins. Could the valve have partially closed and be stuck, restricting the in flow?

Could the valve have partially closed and be stuck, restricting the in flow?
Yes, if it is a gate valve. Replace.

Hi James

If you have an older style gate valve then yes, certainly is possible that the valve has broken off and is restricting flow.

To test your theory, attach a hose to the water heater drain and then simply open the drain (and point hose out to yard or into a tub/large sink)... see what happens.

If pressure starts good and "bleeds off" then you can be pretty sure you need a new shut off valve. If pressure/volume remain constant then the issue is at the nipple of the hot water outlet or further down the line, right?

Try this test and let us know what happens, OK?

Mark