Plumbing Questions? Ask a Plumber and Get Answers ASAP.
Welcome to Just Answer, my name is ***** ***** I will do my best to help you with your issue. First I’ll need some more info so I have a more complete picture of you situation.
What is the brand and model number of your water heater?
If you aren't getting any error messages when this happens the first thing to do is to clean the filter screen at the cold water inlet connection. It's a cap on the side of the fitting. Turn off the water into the unit, then open a hot water (only) faucet until it stops running then close it and unscrew the cap (the filter screen is attached). Clean the screen off then reinstall the cap and turn the water back on. Have a bucket handy since some water will likely remain in the piping and it may drain out when you remove the cap.
You have to go to the unit and check the display for an error code when this happens. A dirty filter is THE most common cause of this type of problem if there is no error showing on the display. No sediment filter removes everything
I have been called away. I should be back in less than an hour. I'll respond when I get back if you have more questions.
This thread won't go away and I'll answer related follow up questions even after you rate me favorably. If cleaning the screen doesn't help then the next time this happens go to the unit and tell me what's on the display.
You can try white Vinegar. Also, if you're water is that hard do you regularly (once a year 2 tops) do an acid flush of the heat exchanger?
You can use a fair amount of force but if it won't come off with medium sized channel lock pliers and something short of all your strength then it's best to leave it alone until/unless you are prepared to replace it.